EP4522801A1

EP4522801A1 - Alternative fibers and micro-fibrillated cellulose coated packaging papers, and films and substrates

Info

Publication number: EP4522801A1
Application number: EP23804300.4A
Authority: EP
Inventors: Lokendra Pal; Preeti TYAGI; Norman LISSON; Mrittika DEBNATH; Roman SARDER
Original assignee: North Carolina State University; WM Wrigley Jr Co
Current assignee: North Carolina State University; WM Wrigley Jr Co
Priority date: 2022-05-12
Filing date: 2023-05-12
Publication date: 2025-03-19
Also published as: CN119343499A; EP4522801A4; US20250304344A1; WO2023220337A1

Abstract

Sustainable paper-based packaging materials, e.g., packaging materials comprising agro-based microfibrillated cellulose (A-MFC), are described. The packaging materials include coatings and films prepared from A-MFC derived from hemp hurds, cocoa pod husks, and other agro-residues or byproducts and having a high level of primary and/or secondary fines. Methods of preparing the A-MFC can involve a reduced amount of energy compared to wood-derived materials and the packaging materials can have enhanced barrier and mechanical properties, such as enhanced oil and grease resistance.

Description

DESCRIPTION ALTERNATIVE FIBERS AND MICRO-FIB RILLATED CELLULOSE COATED PACKAGING PAPERS, AND FILMS AND SUBSTRATES

CROSS REFERENCE TO RELATED APPLICATIONS This application claims benefit of and priority to U.S. Provisional Patent Application Serial No. 63/364,613, filed May 12, 2022, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The presently disclosed subject matter relates to non-wood biopolymer fibers, e.g., agro-based micro-fibrillated cellulose (A-MFC), and their use in packaging materials, e.g., for food and/or beverage packaging. The non-wood biopolymer fibers can include fibers derived from non-wood wood lignocellulosic feedstocks, including agricultural residues and industrial lignocellulosic waste, and/or which have a high level of primary and/or secondary fines and that have been micro-fibrillated and optionally chemically modified. The fibers can be incorporated into films or coating or composite layers for packaging materials with enhanced tensile strength and stretch, while also having a barrier to oil, grease, water, water vapor, air, and oxygen.

ABBREVIATIONS % = percent

°C = degrees Celsius peq = microequivalent pm = micrometer

AGU = anhydroglucose

AH = autohydrolyzed

AKD = alkyl ketene dimer

A-MFC = agro-based microfibrillated cellulose CFS = cocoa fruit shell

CH or Chi = chitosan cm = centimeter

CM = carboxymethylation CM2 enhanced chemicals carboxymethylation

CMA chloroacetic acid sodium salt

CMC carboxymethyl cellulose

CMPI carboxymethylation followed by periodate oxidation (or

MFC from fibers that are both carboxymethylated and periodate oxidized)

CM-PI mixture of carboxymethylated MFC and periodate oxidized MFC

CNC cellulose nanocrystals

CPH cocoa pod husk

CPS or cP centipoise

CS or St or ST = cationic starch

DAC dialdehyde cellulose

DP degree of polymerization

DS degree of substitution

FTIR Fourier-transform infrared g gram

GL or GLY or Gly = glycerol

GS Gurley seconds gsm grams per square meter

HH hemp hurds

HM hemp mix

HW hardwood

KWH/T kilowatt-hour per ton

1 liter

MFC micro-fibrillated cellulose min = minutes ml milliliter mm = millimeter

OGR oil and grease resistance PI = periodate oxidation rpm = revolutions per minute

RT = room temperature

SAP = superabsorbent polymers

SEM = scanning electron microscope

TEM = transmission electron microscope

UCPH = unbleached cocoa pod husk

WVTR = water vapor transmission rate

BACKGROUND Food packaging plays a significant role in daily life and in the current economy. Food packaging can help to promote a food’s value, to reduce food waste, and to reduce food spoilage by preserving food quality during storage, transport, and delivery, as well as through other useful features (Gutta et al., 2013).

According to a recent study, the global packaging market is set to reach over $1 trillion by 2021 (Smithers, 2018). However, growth in the packaging market has also raised concerns about environmental sustainability. Every year, large amounts of packaging materials are used with the intention of “use and throw,” and a large portion of these materials are also made of non-biodegradable and non-renewable materials, such as plastics, glass, and metals. Plastic polymers used in food packaging can have adverse effects on both human health and the environment. These single and short use plastic polymers can be thrown away as solid waste, which can end up in landfills and can ultimately end up in the soil and ocean waterways (MacArthur et al., 2016)(Jambeck et al., 2015).

Consumer demand for sustainability and recent changes in government policies and regulations, such as the initiatives to ban or reduce the use of plastics, especially single-use plastics, has led businesses to consider alternative solutions. Further, the increasing preference from consumers for convenience, small package sizes, and for minimally processed, fresh, and healthy foods has resulted in a desire for highly functional and sustainable food packaging (Tyagi et al., 2022). Thus, there is an interest in sustainable and/or biodegradable packaging in a number of markets, including in the food and beverage industry, to overcome the challenges of functionality, environmental stewardship, and cost, while maintaining an acceptable biodegradation profile. Accordingly, there is an ongoing need for new sustainable food packaging materials and methods of preparing food packaging materials from sustainable source materials, including biomass materials that are currently considered to be low-value byproducts and/or waste.

SUMMARY

The presently disclosed subject matter now will be described more fully hereinafter, in which some, but not all embodiments of the presently disclosed subject matter are described. Indeed, the presently disclosed subject matter can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

In some embodiments, the presently disclosed subject matter provides a packaging material comprising a film or a coating layer comprising agro-based microfibrillated cellulose (A-MFC), wherein said A-MFC comprises a microfibrillated cellulose (MFC) prepared from a pulp from a non- wood lignocellulosic feedstock, wherein the film or coating layer has a weight gain of less than about 5 percent (%) and/or less than about 2.5 grams per square meter (g/m²), when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees Celsius (°C).

In some embodiments, the non-wood lignocellulosic feedstock comprises one or more agricultural residue and/or industrial by-product. In some embodiments, the nonwood lignocellulosic feedstock is selected from the group comprising hemp hurds, a mixture of hemp hurds and hemp bast, bagasse, cocoa pod husks, and combinations thereof.

In some embodiments, the A-MFC comprises modified A-MFC, wherein the modified A-MFC comprises MFC derived from a chemically modified pulp. In some embodiments, the modified A-MFC comprises carboxymethylated A-MFC; oxidized A- MFC; carboxymethylated and oxidized MFC; or a combination thereof. In some embodiments, the oxidized A-MFC comprises dialdehyde cellulose.

In some embodiments, the film or coating layer comprises about 5 weight percent (wt%) to about 90 wt% A-MFC, optionally wherein the film or coating layer comprises about 40 wt% A-MFC to about 80 wt% A-MFC. In some embodiments, the film or coating layer further comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a polyhydroxyalkanoate (PHA), and alkyl ketene dimer (AKD). In some embodiments, the A-MFC has a total fines level of about 50% to about 95%. In some embodiments, the A-MFC has an average fiber length of about 0.1 mm to about 0.45 mm.

In some embodiments, the film or coating layer has a thickness of about 1 micrometer to about 200 micrometers, optionally wherein the film or coating layer is a coating layer with a thickness of about 1 micrometer to about 30 micrometers or a film with a thickness of about 10 micrometers to about 200 micrometers, further optionally wherein the film has a thickness of about 20 micrometers to about 140 micrometers. In some embodiments, the film or coating layer has a bulk of about 0.5 cubic centimeters per gram (cm³/g) to about 2.0 cm³/g.

In some embodiments, the film or coating layer has a weight gain of less than about 2% and/or less than about 1.19 g/m², when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees C. In some embodiments, the film or coating layer has a weight gain of less than about 3% and/or less than about 1.8 g/m² when contacted with room temperature oil for 15 hours.

In some embodiments, the film or coating layer has a water vapor transmission rate (WVTR) of less than 50 grams per square meter millimeter per day (g/m².mm/day), optionally less than 15 g/m².mm/day. In some embodiments, the film or coating layer has a density of about 0.3 grams per cubic centimeter (g/cm³) to about 2.1 g/cm³. In some embodiments, the film or coating layer has a tensile index of about 30 Newton meter per gram (Nm/g) or more. In some embodiments, the film or coating layer has a stretch of about 1.5% or higher.

In some embodiments, the packaging material is a food or beverage packaging material. In some embodiments, the packaging material further comprises a substrate, wherein said substrate is coated on at least one surface by the film or coating layer comprising A-MFC, optionally wherein the substrate is a flexible substrate. In some embodiments, the substrate comprises paper or another biodegradable and/or sustainable material, optionally wherein the paper comprises or consists of papermaking fibers derived from a waste biomass.

In some embodiments, the presently disclosed subject matter provides a method for preparing a film that has a weight gain of less than about 5 percent (%) and/or less than about 2.5 grams per square meter (g/m²), when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees Celsius (°C), the method comprising: (a) preparing a suspension comprising agro-based microfibrillated cellulose (A-MFC), wherein said A- MFC is microfibrillated cellulose (MFC) prepared from a pulp from a non-wood lignocellulosic feedstock; (b) forming a web using from the suspension; and (c) drying the web, thereby providing the film. In some embodiments, the non-wood lignocellulosic feedstock comprises one or more agricultural residue and/or industrial byproduct, optionally wherein the non-wood lignocellulosic feedstock comprises hemp hurds, a mixture of hemp hurds and hemp bast, cocoa pod husks, or a combination thereof.

In some embodiments, preparing the suspension comprising A-MFC comprises fibrillating a suspension of pulp from a non-wood lignocellulosic feedstock, wherein said pulp has a primary fines level of more than 10%, optionally wherein the pulp has a primary fines level of about 15 % to about 50%. In some embodiments, the pulp is a kraft pulped pulp, an autohydrolyzed pulp, an unbleached pulp, higher yield pulp, or higher lignin containing pulp. In some embodiments, the method further comprises chemically modifying the pulp in an aqueous medium prior to fibrillation. In some embodiments, chemically modifying the pulp comprises carboxymethylating the pulp, oxidizing the pulp, or carboxymethylating and oxidizing the pulp. In some embodiments, the method comprises carboxymethylating the pulp prior to or after fibrillation.

In some embodiments, preparing the suspension comprising A-MFC comprises contacting the A-MFC with a liquid, optionally water, to provide a suspension comprising a total solids content comprising at least about 50 weight percent (wt%) of the A-MFC, optionally to provide a suspension comprising a total solids content comprising about 50 wt% to about 80 wt% A-MFC. In some embodiments, the suspension has a solids content of about 2.0% or higher and/or about 5% or lower. In some embodiments, the suspension comprising A-MFC further comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a polyhydroxyalkanoate (PHA), and alkyl ketene dimer (AKD). In some embodiments, preparing the suspension comprises mixing the suspension at a temperature between about room temperature and about 80 degrees Celsius (°C) for a period of time, optionally for about 30 minutes.

In some embodiments, step (b) comprises casting a web from the suspension. In some embodiments, the method further comprises applying the film to a surface of a substrate, optionally a paper substrate, to provide a film coated substrate. In some embodiments, the method further comprises forming a packaging material from the film or from a film coated substrate.

Accordingly, it is an object of the presently disclosed subject matter to provide packaging materials comprising A-MFC prepared from an agro-based pulp and methods of making the materials. This and other objects are achieved in whole or in part by the presently disclosed subject matter.

An object of the presently disclosed subject matter having been stated above, other objects and advantages of the presently disclosed subject matter will become apparent to those of ordinary skill in the art after a study of the following description of the presently disclosed subject matter and non-limiting Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a composite diagram comprising photographic images and schematic drawings showing the generation of micro-fibrillated cellulose (MFC) using a Masuko grinder.

Figures 2A and 2B are graphs showing the Fourier-transform infrared (FTIR) spectra (percent (%) transmittance versus wavenumber (in inverse centimeters (cm ¹))) of different fibers. Figure 2 A shows, from bottom to top, the spectra for unmodified hemp hurds fibers (HH), HH modified by carboxymethylation (CM-HH), HH modified by carboxymethylation followed by periodate oxidation (CMP1-HH), and HH modified by periodate oxidation (Pl- HH). Figure 2B shows the spectra of HH, hardwood fibers modified by carboxymethylation (CM-HW), and CM-HH.

Figure 3 is a graph showing the relative degree of substitution (DS) of carboxymethylation of different samples of fibers: hemp hurds modified by carboxymethylation (CM-HH), hemp mix (HM) modified by carboxymethylation, hardwood (HW) modified by carboxymethylation, and hemp hurds carboxy methylated with a higher amount of monochloracetic acid sodium salt (CM2-HH) (i.e., compared to the amount of monochloroacetic acid sodium salt used to carboxymethylated the other samples.

Figure 4 is a graph showing the percentage of primary fines in various treated and untreated fibers prior to preparation of micro-fibrillated cellulose (MFC) from the fibers. The left-hand axis shows the average fiber length (in millimeters (mm)), while the righthand axis shows the percentage (%) of primary fines of fibers from the following sources: hemp hurds (HH), HH modified by carboxymethylation (CM-HH), HH modified by periodate oxidation (PI-HH), unrefined hardwood (HW (Unrefined)), refined hardwood (HW (2.5 rev-PFI)), unrefined softwood (SW (Unrefined)), refined softwood (SW (5k rev- PFI)), and cocoa pod husks (CPH). Fines % (bars) and fiber length values (dashed line) are also provided in the chart under the graph. Figure 5 is a graph showing energy consumption during the micro-fibrillation process of various modified and unmodified fibers and the fines level of the resulting micro- fibrillated cellulose (MFC). Energy consumption (in kilowatt-hours per ton (KWH/T)) is shown in the left-hand axis and percentage (%) of fines in the right-hand axis. Values are provided for MFC prepared from hemp hurds (HH-MFC), MFC prepared from hemp hurds (HH) modified by carboxy methylation (CM-HH-MFC), MFC prepared from HH modified by enhanced chemical carboxymethylation (CM2-HH-MFC), MFC prepared from HH modified by periodate oxidation (PI-HH-MFC), MFC prepared from HH modified by carboxymethylation and periodate oxidation (CMPI-HH-MFC), MFC prepared from hemp mix modified by carboxymethylation (CM-HM-MFC), MFC prepared from hardwood (HW) fiber modified by carboxymethylation (CM-HW-MFC), and MFC prepared from cocoa pod husk (CPH-MFC). Fines % (dashed line) and energy consumption (bars) are also provided in the chart under the graph.

Figure 6 is a graph showing the fiber length (in millimeters (mm)) and percentage (%) of fines in various modified and unmodified fibers before or after micro-fibrillation. Values are provided for fiber from hump hurds (HH), fiber from HH modified by carboxymethylation (CM-HH), micro-fibrillated cellulose (MFC) prepared from CM-HH (CM-HH-MFC), HH modified by periodate oxidation (PI-HH), MFC from PI-HH (PI-HH- MFC), enhanced chemicals CM-HH (CM2-HH), MFC prepared from the CM2-HH (CM2- HH-MFC), and MFC prepared from cocoa pod husk (CPH-MFC). Fines % (bars) and fiber length values (dashed line) are also provided in the chart under the graph.

Figure 7 is a graph of the viscosity (in centipoise (cP)) of different micro-fibrillated cellulose (MFC), including MFC prepared from hemp hurds (HH) modified by carboxymethylation (CM-HH-MFC), MFC prepared from HH modified by periodate oxidation (PI-HH-MFC), and MFC prepared from HH modified by carboxy methylation and periodate oxidation (CMPI-HH-MFC).

Figure 8 is a graph showing the anionic charge (in microequivalents per liter (peq/1) of different micro-fibrillated cellulose (MFC), including MFC prepared from hemp mix (HM) modified by carboxymethylation (CM-HM-MFC), MFC prepared from hardwood (HW) fiber modified by carboxymethylation (CM-HW-MFC), MFC prepared from hemp hurds (HH) modified by carboxymethylation (CM-HH-MFC), MFC prepared from HH modified by periodate oxidation (PI-HH-MFC), MFC prepared from HH modified by enhanced chemicals carboxymethylation (CM2-HH-MFC), and MFC prepared from HH modified by carboxymethylation and periodate oxidation (CMPI-HH-MFC). Figure 9 is a graph showing the carboxyl content (in milliequivalents per 100 grams (mEq/lOOg)) of different micro-fibrillated cellulose (MFC), including MFC prepared from hemp mix (HM) modified by carboxymethylation (CM-HM-MFC), MFC prepared from hardwood (HW) fiber modified by carboxymethylation (CM-HW-MFC), MFC prepared from hemp hurds (HH) modified by carboxymethylation (CM-HH-MFC), MFC prepared from HH modified by periodate oxidation (PI-HH-MFC), MFC prepared from HH modified by enhanced chemicals carboxy methylation (CM2-HH-MFC), and MFC prepared from HH modified by carboxymethylation and periodate oxidation (CMP1-HH-MFC).

Figure 10 shows scanning electron microscope (SEM) images of micro-fibrillated cellulose (MFC) samples prepared from unmodified and modified hemp hurds fibers (HH). The images in the left-hand column are of MFC prepared from unmodified hemp hurds (HH-MFC), the images in the column second from the left are of MFC prepared from carboxymethylated hemp hurds (CM-HH-MFC), the images in the column second from the right are of a mixture of MFC prepared from carboxymethylated hemp hurds and MFC prepared from periodate-oxidized hemp hurds (CM-PI-HH-MFC) and the images in the right-hand column are of MFC prepared from periodiate-oxidized hemp hurds (Pl-HH- MFC). The images were taken at three different magnifications which are 500 times (500x, top row), 1000 times (lOOOx, middle row) and 5000 times (5000x, bottom row) magnification.

Figure 11 shows transmission electron microscope (TEM) images of MFC samples made from unmodified and modified hemp hurds fiber. From left to right, the images are of MFC prepared from unmodified hemp hurds (HH-MFC), MFC prepared from carboxymethylated hemp hurds (CM-HH-MFC), a mixture of MFC prepared from carboxymethylated hemp hurds and MFC prepared from periodate-oxidized hemp hurds (CM-PI-HH-MFC), and MFC prepared from periodate-oxidized hemp hurds (PI-HH-MFC). The images were taken at 5000 times (5000x) magnification for all the samples. The scale bar in the lower left corner of each image represent 2 micrometers (pm).

Figure 12 is a schematic diagram comprising a series of photographic images showing the workflow for a process for making a coating film from micro-fibrillated cellulose via a solvent casting method.

Figures 13A-13E are graphs showing the viscosity (in centipoise (CPS)) of different coating/film formulations comprising various types of biopolymers at different revolutions per minute (rpm). Figure 13A shows the viscosity of aqueous formulations prepared from solids mixtures comprising 100 % micro-fibrillated cellulose (MFC) prepared from hemp hurds (HH-MFC) mixed at 80 degrees (°) Celsius (HH-MFC(100)-80T) (data shown by circles and solid line); comprising 80% HH-MFC and 20% chitosan (CH) mixed at 80° Celsius (HH-MFC(80)-CH(20)-80T) (data shown by diamonds and dotted line); comprising 80% HH-MFC, 20% CH, and 2% glycerol (GL) mixed at 80° Celsius (HH-MFC(80)- CH(20)-GL(2)-80T) (data shown by triangles and solid line); and comprising 80% HH- MFC, 20% CH and 2% GL mixed at room temperature (RT) (HH-MFC(80)-CH(20)-GL(2)- RT) (data shown by squares and dashed line). Figure 13B shows the viscosity of aqueous formulations prepared from solids mixtures comprising 80% micro-fibrillated cellulose prepared from hemp hurds modified by carboxymethylation (CM- HH-MFC), 20% chitosan, and 2% glycerol and mixed at room temperature (CM-HH-MFC(80)-CH(20)-GL(2)-RT) (data shown by circles and solid line); comprising 80% CM-HH-MFC, 20% chitosan and 2% glycerol and mixed at 80 degrees Celsius (CM-HH-MFC(80)-CH(20)-GL(2)-80T) (data shown by circles and dashed line); comprising 80% CM-HH-MFC and 20% chitosan mixed at 80 degrees Celsius (CM-HH-MFC (80)-CH(20)-80T) (data shown by diamonds and dashed line); and comprising 100% CM-HH-MFC mixed at 80 degrees Celsius (CM-HH- MFC-80T) (data shown by triangles and dashed and dotted line). Figure 13C shows the viscosity of aqueous formulations prepared from solids mixtures comprising 80% micro- fibrillated cellulose derived hemp hurds modified by carboxymethylation followed by periodate oxidation (CMPI-HH-MFC), 20% chitosan and 2 % glycerol mixed at 80 degrees Celsius (CMPI-HH-MFC-(80)-CH(20)-GL(2)-80T) (data shown by triangles and dotted line); comprising 80% CMPI-HH-MFC, 20% chitosan, and 2% glycerol mixed at room temperature (CMPI-HH-MFC(80)-CH(20)-GL(2)-RT) (data shown by circles and solid line); comprising 80% CMPI-HH-MFC and 20% chitosan mixed at 80 degrees Celsius (CMPI-HH-MFC(80)-CH(20)-80T) (data shown by squares and solid line); and comprising 100% CMPI-HH-MFC mixed at 80 degrees Celsius (CMPI-HH-MFC100-80T) (data shown by diamonds and solid line). Figure 13D shows the viscosity of aqueous formulations prepared from solids mixtures comprising 80% micro-fibrillated cellulose derived from cocoa pod husks (CPH-MFC), 20% chitosan, and 2% glycerol mixed at 80 degrees Celsius (CPH-MFC (80)-CH(20)-GL(2)-80T) (data shown by squares and dotted line); comprising 80% CPH-MFC and 20% chitosan mixed at 80 degrees Celsius (CPH-MFC(80)-CH(20)- 80T) (data shown by circles and solid line); comprising 80% CPH-MFC, 20% chitosan, and 2% glycerol mixed at room temperature (CPH-MFC(80)-CH(20)-GL(2)-RT) (data shown by diamonds and solid line); and comprising 100% CPH-MFC solids only mixed at 80 degrees Celsius (CPH-MFC(100)-80T) (data shown by triangles and solid line). Figure 13E shows the viscosity of aqueous formulations prepared from solids mixtures comprising 80% cocoa pod husk fibers, 20% chitosan, and 2% glycerol mixed at room temperature (CPH Fiber (80)-CH(20)-GL(2)-RT) (data shown by circles and solid line); comprising 80% cocoa pod husk fibers, 20% chitosan, and 2% glycerol mixed at 80 degrees Celsius (CPH Fiber(80)-CH(20)-GL(2)-80T) (data shown by squares and solid line); comprising 80% cocoa pod husk fibers and 20% chitosan mixed at 80 degrees Celsius (CPH Fiber(80)- CH(20)-80T) (data shown by triangles and dashed line); and comprising 100% cocoa pod husk fibers mixed at 80 degrees Celsius (CPH Fiber(100)-80T) (data shown by diamonds and dotted line).

Figures 14A-14D are graphs showing the bulk (cubic centimeters per gram (cm³/g)) of films prepared from formulations of various modified and unmodified micro-fibrillated cellulose (MFC) or pulps. Figure 14A shows the bulk of films prepared from formulations comprising MFC prepared from unmodified hemp hurds (HH) and cocoa pod husks (CPH); CPH pulp fiber (CPH-Fibers); or MFC from carboxymethylated fibers (CM-MFC). Some of the formulations were also based on solids mixtures comprising 20% chitosan (CH)and 2% glycerol (GL). The formulations were all mixed at 80 degrees Celsius (80T). Figure 14B shows the bulk of films prepared from formulations comprising (left) MFC from unmodified hemp mix (HM), HH, CPH, unbleached CPH (UCPH), or auto hydrolyzed hemp hurds (AH-HH) or (right) MFC from carboxymethylated hemp mix (CM-HM-MFC), or carboxymethylated followed by periodate oxidized HM (CMPI-HM-MFC). Some of formulations were based on solids mixtures comprising 50% or 20% chitosan (CH), 20% CH and 1% alkyl ketene dimers (AKD) or 45% CH and 5% glycerol (GL) and were prepared at room temperature (RT) or 80 degrees Celsius (80T). Figure 14C shows the bulk of films prepared from formulations comprising (left) MFC from unmodified HH (HH-MFC), or (right) MFC from carboxymethylated hemp hurds (CM- HH-MFC), carboxymethylated hemp mix (CM-HM-MFC). Some of formulations were based on solids mixtures comprising 20% chitosan (CH), or 20% CH in combination with 1% glycerol (GL) and were prepared at room temperature (RT) or 80 degrees Celsius (80T). Figure 14D shows the bulk of films prepared from formulations based on a solids mixture comprising (left) 80% unmodified MFC derived from HH, 20% cationic starch (St) or 20% CH, and 2% GL at RT or 80T; (middle) 80% MFC prepared from carboxymethylated HH (i.e., CM-HH-MFC) with 20% St or 20% CH and 2% GL at RT or 80T; and (right) mixtures of 80% CM-HH- MFC and 20% MCF prepared from periodate oxidized hemp hurds (PI-HH-MFC), with or without 20% St or 20% CH and 2% GL at RT.

Figures 15A-15C show scanning electron micrograph (SEM) images of films prepared from different formulations of microfibrillated cellulose (MFC). Figure 15A is a series of SEM images of films prepared from formulations comprising MFC from unmodified hemp hurds (HH or HH-MFC), MFC from carboxymethylated hemp hurds (CM-HH-MFC), a mixture of MFC from carboxymethylated hemp hurds and MFC from periodate-oxidized hemp hurds (CM-PT) or MFC from carboxymethylated and periodate- oxidized hemp hurds (CMPI). Some of the formulations also included one or more of cationic starch (St), chitosan (CH) and glycerol (GL). The formulations were prepared at either 80 degrees Celsius (80) or room temperature (RT). The images are at 100 times (lOOx) magnification. Figure 15B is a pair of SEM images showing a film prepared from a formulation comprising carboxymethylated hemp hurds, chitosan and glycerol at room temperature (CM-HH-MFC (80)-CH(20)-GL(20)-RT). On the left is an image at lOOx magnification, while on the right is an image at 1000 times (lOOOx) magnification. Figure 15C is a pair of SEM images showing a film prepared from a formulation of the same composition as the formulation used for the film of Figure 15B, but where the formulation was prepared at 80 degrees Celsius (CH-HH-MFC(80)-CH(20)-GL(2)-80T). On the left is an image at lOOx magnification, while on the right is an image at 1000 times (lOOOx) magnification.

Figures 16A-16D are graphs showing the Fourier- transform infrared (FTIR) spectra (percent (%) transmittance versus wavenumber (in inverse centimeters (cm ¹))) of different polymers, microfibrillated cellulose (MFC), MFC composites and MFC composites with chitosan (CH), CH and glycerol (GL or GLY) or with cationic starch (ST) and GL. Figure 16A shows the FTIR spectra for CH and composites prepared from formulations comprising unmodified hemp hurds-derived MFC (HH-MFC) with or without CH or CH and GLY where formulations were prepared at room temperature (RT) or 80 degrees Celsius (80T). Figure 16B shows the FTIR spectra of CH and composites prepared from formulations comprising MFC derived from carboxymethylated hemp hurds (CM or CM-MFC) at RT or 80T with or without CH or CH and GLY. Figure 16C shows the FTIR spectra of chitosan, MFC prepared from periodate-oxidized hemp hurds (PI-HH), a composite prepared from a formulation comprising a mixture of MFC prepared from periodate-oxidized hemp hurds and MFC prepared from carboxymethylated hemp hurds (CM-PI), a composite prepared from a formulation comprising CM-PI, CH, and GY, and a composite prepared from a formulation comprising CM-PI-ST and GL. The formulations for the composites were prepared at room temperature (RT). Figure 16D is a graph showing the FTIR spectra of cationic starch (ST), and composites prepared from formulations comprising MFC prepared from unmodified hemp hurds (HH), ST, and GL at either room temperature (RT) or at 80 degrees Celsius (HH-ST-GL-RT and HH-ST-GL-80T), MFC from carboxymethylated hemp hurds (CM), ST, and GL at either RT or 80 degrees Celsius (CM-ST-GL-RT and CM- ST-GL-80T) or a mixture of MFC from periodate-oxidized hemp hurds and MFC from carboxymethylated hemp hurds (CM-PI), ST and GL and RT (CM-PT-ST-GL-RT).

Figure 17 is a schematic diagram showing the formation of a network between carboxymethylated cellulose and chitosan.

Figure 18 is a series of photographic images showing the steps for performing a hot oil absorption test on films of the presently disclosed subject matter and possible outcomes of the test.

Figures 19A-19D are graphs showing the weight gain of different films made with various modified and unmodified microfibrillated cellulose (MFC) composites in (Figures 19 A and 19B) a hot oil test and (Figures 19C and 19D) a room temperature oil test. Weight gain is measured as a percentage (%) of the original film weight (Figures 19A and 19C) or in grams per square meter (gsm, Figures 19B and 19D). Figures 19A and 19B show data from films prepared from formulations comprising (left) 100% unmodified hemp hurds MFC (HH-MFC), 80% HH-MFC and 20% chitosan (CH), or 80% HH-MFC, 20% CH or cationic starch (ST) and 1% glycerol (GL) at room temperature (RT) or 80 degrees Celsius (80T); (middle) 100% carboxymethylated hemp hurds (CM-HH-MFC), 80% CM-HH-MFC and 20% CH, or 80% CM-HH-MFC, 20% CH or ST, and 1% GL at RT or 80T; and (right) mixtures of CM-HH-MFC and MFC from periodate-oxidized hemp hurds (PI-HH-MFC), mixtures of the modified MFC and CH, or mixtures of the modified MFC and ST. Figures 19C and 19D show weight gain in films produced from formulations comprising 50% MFC from autohydroylzed hemp hurds (AH-HH-MFC) and 50% CH prepared at room temperature (AH-HH-MFC(50)-CH(50)-RT; MFC from unbleached cocoa pod husks (UCPH); 50% UCPH and 50% CH prepared at RT (UCPH-MFC(50)-CH(50)-RT, 80% CM-HH-MFC and 20% CH prepared at 80 degrees Celsius (CM-HH-MFC(80)-CH(20)- 80C), 50% MFC from cocoa pod husks and 50% CH prepared at 80 degrees Celsius (CPH- MFC(50)-CH(50)-80C), MFC from carboxymethylated and periodate oxidized hemp hurds (CMPLHH), 50% CMPI-HH and 50% CH prepared at room temperature (CMPL HH(50)_CH(50)_RT), MFC from a carboxymethylated hemp mix (CM-HM-MFC), 50% MFC from hemp mix and 50% CH prepared at RT (HM-MFC(50)-CH(50)-RT), 80% MFC from hemp mix and 20% CH prepared at RT (HM-MFC(80)-CH(20)-RT), and 80% MFC from hemp mix and 20% CH and 1% alkyl ketene dimer (AKD) prepared at 80 degrees Celsius (HM-MFC(80)-CH(20)-AKD(l)-80C).

Figures 20A-20F are graphs showing (Figures 20A-20D) the water vapor transmission rate (WVTR) of films prepared from formulations made of various modified and unmodified microfibrillated cellulose (MFC), (Figure 20E) the density of different films; and (Figure 20F) the relationship between density and WVTR. Figure 20A shows the WVTR for composite films prepared from formulations comprising (left) unmodified MFC from hemp hurds (HH-MFC) or cocoa pod husks (CPH-MFC), (middle) cocoa pod husk pulp fibers (CPH Fibers), and (right) MFC from carboxymethylated material (CM- MFC). The formulations were all mixed at 80 degrees Celsius (80T). Some of the formulations also included chitosan (CH) or CH and glycerol (GL). Figure 20B shows the WVTR for composite films prepared from formulations comprising MFC from hemp mix (HM-MFC), hemp hurds (HH-MFC), CPH, unbleached CPH (UCPH-MFC), autohydrolyzed hemp hurds (AH-HH-MFC), carboxymethylated hemp mix (CM-HM- MFC), carboxymethylated followed by periodate-oxidized hemp mix (CMPI-HM-MFC) carboxymethylated CPH (CM-CPH-MFC). The formulations were mixed at room temperature (RT) or 80T). Some of the formulations included CH, CH and GL, or CH and alkyl ketene dimer (AKD). Figure 20C shows the WVTR of films prepared from formulations comprising MFC from (left) unmodified hemp hurds (HH-MFC) or (right) carboxymethylated MFC. The formulations were mixed at RT or 80T. Some of the formulations included CH and GL. Figure 20D shows the WVTR of films prepared from formulations comprising (left) MFC from hemp hurds (HH-MFC), (middle) MFC from carboxymethylated hemp hurds (CM-HH-MFC), and (right) mixtures of CM-HH-MFC and MFC from periodate-oxidized hemp hurds (PI-HH-MFC). The formulations were mixed at RT or 80T. Some of the formulations included CH and GL or cationic starch (ST) and GL. Figure 20E compares the density of films prepared from formulations comprising (left) MFC from hemp mix (HM-MFC) and (right) MFC prepared from hemp hurds (HH-MFC). WVTR is expressed in grams per square meter millimeter per day (g/m².mm/day) and density in grams per cubic centimeter (g/cm³).

Figures 21 A and 21B are photographic images of results of kit testing films for oil and grease resistance. Figure 21A shows exemplary results observed when a film passes a kit test, while Figure 21B shows exemplary results observed when a film fails a kit test. Figure 22 is a series of photographic images showing the workflow for assessing the oil and grease resistance of the presently disclosed films after creasing.

Figures 23A-23C are photographic images of water resistance results for exemplary films of the presently disclosed subject matter. Figure 23A is an image showing a film prepared from 100% unmodified cocoa pod husk (CPH) microfibrillated cellulose (MFC) prepared at 80 degrees Celsius (CPH-MFC (100)-80T dispersing after two hours in water. Figure 23B is an image showing that a film prepared from carboxymethylated hemp hurds MFC (CM-HH-MFC) remained intact after 7 days in water. Figure 23C is an image showing that the CM-HH-MFC film remained intact after 32 days in water.

Figure 24 is a graph showing the air resistance (measured in Gurley seconds) of different films comprising cocoa pod husk (CPH) fibers and microfibrillated cellulose from cocoa pod fibers (CPF-MFC ): a film prepared from 100% CPH Fibers at 80 degrees Celsius (CPH-Fibers (100)-80T); a film prepared from 80% CPH-Fibers and 20% chitosan (CH) at 80 degrees Celsius (CPH-Fibers (80)-CH(20)-80T); a film prepared from 80% CPH Fibers, 20% CH, and 2% glycerol (GL) at 80 degrees Celsius (CPH-Fibers (80)-CH(20)-GL(2)- 80T; and a film prepared from 80% CPH-MFC, 20% CH, and 2% GL at room temperature (CPH-MFC(80)-CH(20)-GL(2)-RT).

Figures 25A-25D are a series of graphs showing the tensile properties of different films made of various modified and unmodified microfibrillated cellulose (MFC) fiber composites. Tensile index (tensile strength divided by basis weight) is reported in Newton meter per gram (Nm/g). Figure 25A shows the tensile index for composite films prepared from formulations comprising (left) unmodified MFC from hemp hurds (HH-MFC) or cocoa pod husks (CPH-MFC), (middle) cocoa pod husk pulp (CPH Fibers), and (right) MFC from modified hemp hurds (CM-HH-MFC). The formulations were all mixed at 80 degrees Celsius (80T). Some of the formulations also included chitosan (CH) or CH and glycerol (GL). Figure 25B shows the tensile index for composite films prepared from formulations comprising MFC from hemp mix (HM-MFC), hemp hurds (HH-MFC), CPH (CPH-MFC), unbleached CPH (UCPH-MFC), autohydrolyzed hemp hurds (AH-HH-MFC), carboxymethylated hemp mix (CM-HM-MFC), or carboxymethylated followed by periodate-oxidized hemp mix (CMPI- HM-MFC). The formulations were mixed at room temperature (RT) or 80 degrees Celsius (80T). Some of the formulations included CH, CH and GL, or CH and alkyl ketene dimer (AKD). Figure 25C shows the tensile index of films prepared from formulations comprising MFC from (left) unmodified hemp hurds (HH- MFC) or (right) carboxymethylated MFC (CM-HH-MFC). The formulations were mixed at RT or 80T. Some of the formulations included CH or CH and GL. Figure 25D shows the tensile index of films prepared from formulations comprising (left) MFC from unmodified hemp hurds (HH-MFC), (middle) MFC from carboxymethylated hemp hurds (CM-HH-MFC), and (right) mixtures of CM-HH-MFC and MFC from periodate-oxidized hemp hurds (PI-HH-MFC). The formulations were mixed at RT or 80T. Some of the formulations included CH and GL or cationic starch (ST) and GL.

Figures 26A-26D are a series of graphs showing the stretch (in percentage (%)) of different films made of various modified and unmodified microfibrillated cellulose (MFC) composites. Figure 26 A shows the stretch for composite films prepared from formulations comprising (left) unmodified MFC from hemp hurds (HH-MFC) or cocoa pod husks (CPH- MFC), (middle) cocoa pod husk pulp (CPH Fibers), and (right) MFC from carboxymethylated material (CM-MFC). The formulations were all mixed at 80 degrees Celsius (80T). Some of the formulations also included chitosan (CH) or CH and glycerol (GL). Figure 26B shows the stretch for composite films prepared from formulations comprising MFC from hemp mix (HM-MFC), hemp hurds (HH-MFC), CPH-MFC, unbleached CPH (UCPH-MFC), autohydrolyzed hemp hurds (AH-HH-MFC), carboxymethylated fibers (CM-MFC), carboxymethylated hemp mix (CM-HM-MFC), or carboxymethylated followed by periodate-oxidized hemp mix (CMPI-HM-MFC). The formulations were mixed at room temperature (RT) or 80T. Some of the formulations included CH, CH and GL, or CH and alkyl ketene dimer (AKD). Figure 26C shows the stretch of films prepared from formulations comprising MFC from (left) unmodified hemp hurds (HH-MFC) or (right) carboxymethylated MFC. The formulations were mixed at RT or 80T. Some of the formulations included CH or CH and GL. Figure 26D shows the stretch of films prepared from formulations comprising (left) MFC from unmodified hemp hurds (HH-MFC), (middle) MFC from carboxymethylated hemp hurds (CM-HH-MFC), and (right) mixtures of CM-HH-MFC and MFC from periodate-oxidized hemp hurds (PI- HH-MFC). The formulations were mixed at RT or 80T. Some of the formulations included CH and GL or cationic starch (ST) and GL.

DETAILED DESCRIPTION

The presently disclosed subject matter will now be described more fully hereinafter with reference to the accompanying Examples and Figures, in which representative embodiments are shown. The presently disclosed subject matter can, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this presently described subject matter belongs. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

Throughout the specification and claims, a given chemical formula or name shall encompass all optical and stereoisomers, as well as racemic mixtures where such isomers and mixtures exist.

I. DEFINITIONS

While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently claimed subject matter.

Following long-standing patent law convention, the terms "a", "an", and “the” refer to "one or more" when used herein, including in the claims.

As used herein, the term “about”, when referring to a value or an amount, for example, relative to another measure, is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, and in some embodiments ±0.1% from the specified value or amount, as such variations are appropriate. The term “about” can be applied to all values set forth herein.

As used herein, the term “and/or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and/or D” includes A, B, C, and D individually, but also includes any and all combinations and sub-combinations of A, B, C, and D.

The term “comprising”, which is synonymous with “including,” “containing,” or “characterized by” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. “Comprising” is a term of art used in claim language which means that the named elements are present, but other elements can be added and still form a construct or method within the scope of the claim. As used herein, the phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. When the phrase “consists of’ appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

As used herein, the phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.

With respect to the terms “comprising”, “consisting of’, and “consisting essentially of’, where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

As used herein, “significance” or “significant” relates to a statistical analysis of the probability that there is a non-random association between two or more entities. To determine whether or not a relationship is “significant” or has “significance”, statistical manipulations of the data can be performed to calculate a probability, expressed in some embodiments as a “p-value”. Those p-values that fall below a user-defined cutoff point are regarded as significant. In some embodiments, a p-value less than or equal to 0.05, in some embodiments less than 0.01, in some embodiments less than 0.005, and in some embodiments less than 0.001, are regarded as significant.

As used herein, ranges can be expressed as from “about” one particular value, and/or to “about” another particular value. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed.

"Paper," as used herein, refers to a material constructed of dewatered, pressed and dried together cellulosic and/or lignocellulosic fibers in an aqueous medium, primarily water. For example, a paper can comprise a web of cellulosic and/or lignocellulosic fibers having a top side and a bottom side. In some embodiments, the paper is a planar sheet. In some embodiments, the sheet can have a thin (e.g., less than about 5 mm) edge. Alternatively, the paper can be molded to any desirable shape. In some embodiments, the paper can be bendable. In some embodiments, the paper can be unmalleable such that it retains its shape and structure during ordinary usage as a packaging material, such as a food packaging product. The term "papermaking fibers" as used herein refers to cellulosic and/or lignocellulosic fibers and to fiber mixes comprising cellulosic and/or lignocellulosic fibers. Papermaking fibers include nonwood fibers, such as, but not limited to, cotton , abaca, bamboo, banana, kenaf, grass, flax, straw, jute, hemp, bagasse, milkweed floss, cocoa pod husk and pineapple leaf fibers, and their derivatives and wood fibers such as those obtained from deciduous and coniferous trees, including softwood fibers, such as pines, fir, spruce, cedar, larch, or the like , hardwood fibers, such as eucalyptus, maple, birch, aspen, oak, or the like. Tn some embodiments, the papermaking fibers are fibers from an agricultural and/or industrial waste biomass, such as hemp hurds, mixes containing hemp hurds and hemp bast fibers, and cocoa pod husks. Papermaking fibers can be liberated from their source material by chemical and/or mechanical pulping processes known in the art, such as, but not limited to, the kraft (sulfate) and sulfite chemical pulping processes, where most of the lignin and hemicellulose components are removed, solvent pulping (ethanol-water, organic acids, SO2- ethanol-water, etc.), semi-chemical pulping, enzymatic pulping, chemi-thermomechanical pulping (CTMP), thermomechanical pulping (TMP), hydrothermal pulping, autohydrolysis or hydrothermal pulping, other alkaline (e.g., soda or carbonate) pulping , or any combination of chemical and/or mechanical treatments. Bleaching chemicals such as hydrogen peroxide, oxygen, sodium hydroxide, enzymes, chlorine dioxide, hypochlorite, ozone, peracids, and/or other bleaching agents can be used to whiten the “cellulosic material.” The suitable bleaching techniques can include elemental chlorine free (ECF) or total chlorine free (TCF) bleaching.

The terms “pulping” and “defibration” refer to the process of liberating discrete fibers from a cellulosic or lignocellulosic feedstock.

"Furnishes" and like terminology refers to aqueous compositions including lignocellulosic fibers and optionally additives, such as those typically used in papermaking, including dry strength additives, wet strength resins, and the like. The term “slurry” as used herein refers to an aqueous dispersion of lignocellulosic fibers. In some embodiments, the terms “furnish” and “slurry” can be used interchangeably.

The term “biomass” as used herein refers to a renewable organic material from plants. The term “waste biomass” as used herein refers to biomass materials that are typically underutilized or not utilized and/or considered of low value. Typically, “waste biomass” is a byproduct from an agricultural or industrial process that involves harvesting or otherwise processing a parent biomass material. Thus, for example, waste biomass (or in some embodiments “agro-based”) refer to agricultural residues and byproducts of the processing of other plants.

The term “hemp hurds” as used herein refers to the inner core of the stem of the hemp plant (Cannabis sativa), comprising relatively short xylem fibers and stem pith. Hemp hurds can be separated from the stem by a process referred to as “retting” or via a decortication process. The term “hemp mix” as used herein refers to a mixture of hemp hurds and material from the outer ring of the hemp stem, which can include longer phloem (or “bast”) fibers.

The term “fines” as used herein refers to the fraction of lignocellulosic particles in a pulp or mixture of lignocellulosic fibers that are able to pass through a 200 mesh screen or a perforated plate with a hole diameter of 76 micrometers (pm). The term “primary fines” refers to the fines generated by pulping or by pulping and bleaching a lignocellulosic feed stock. “Total fines” refers to the total amount of primary and “secondary fines”, where “secondary fines” are fines generated by other pulp treatments, e.g., refining and/or chemical modification.

As used herein, the terms “microfibrillated cellulose” or “MFC” refer to cellulosic fibers obtained by fibrillating a cellulose-based pulp. MFC fibers have a high aspect ratio, with average fiber widths in the nanometer range (e.g., between about 5 nm to about 500 nm) and fiber lengths in the micrometer to millimeter range (e.g., between about 0.1 pm to about 1 mm or more). Carboxymethylated microfibrillated cellulose refers to a MFC obtained by fibrillating a carboxymethylated cellulose-based raw material (e.g., pulp). In some embodiments, as described hereinbelow, fibrillation is carried out by mechanical treatment.

II. GENERAL CONSIDERATIONS

Paper is distinct from typical substrates, such as plastics, metals and glass, since cellulose, which is the main component of paper, is relatively reactive under various chemical and thermal processing conditions. It readily absorbs fluids, such as water, grease, and oil. Furthermore, passage of moisture and gaseous materials through paper can be provided by the many air voids and micropores within the fibers. Traditionally, papermakers have relied on extensive refining and surface sizing agents, such as starch, to produce a more closed paper sheet. However, extensive refining can be difficult, particularly with furnishes composed of agro-fibers (i.e., fibers from agricultural feedstocks) due to their high levels of cellulosic fines and the impact of extensive refining on drainage during forming. Even after these treatments, some micropores can remain to provide undesirable fluid and gas flow. According to one aspect of the presently disclosed subject matter, a new generation of flexible food packaging from agro-based fibers is described. In some embodiments, the packaging comprises functional additives and/or chemically modified cellulosic fibers to impart or improve mechanical and/or barrier characteristics.

Cellulose is the most abundant natural polymer on earth. The sustainable development of cellulosic fibers from non-wood biomass has great potential to replace single-use synthetic plastics in packaging and other industrial applications. The valorization of plant-based fibers potentially offers a global platform for developing ecofriendly food packaging and hygiene products. These types of bio-based products are recyclable and can play a significant role in the circular economy. Among the various packaging applications, food packaging holds an important aspect of our daily lives and current economy. As described hereinabove, packaging helps to promote food value, for example, by reducing food waste and chemical contamination by preserving food quality during storage, transport, and delivery, as well as by providing other useful features (Edyta et al., 2015)(Gutta et al., 2013). However, the formability of cellulosic papers is very limited due to its higher degree of deformation and lack of thermoplasticity compared to synthetic polymers, limiting its application (Fengel, 1992). Therefore, to date, extensive utilization of paper-based materials has not been possible in high-quality industrial forming processes and has been limited to simple geometries.

In some embodiments, the presently disclosed subject matter relates to chemical modifications of cellulosic fibers to enhance their usability, e.g., in the preparation of microfibrillated cellulose (MFC) for paper coating, packaging films, and composites development. More particularly, cellulose has three hydroxyl groups on each anhydroglucose unit (AGU) which can be chemically modified in various ways as shown in the Scheme 1, below. The presence of these chemically reactive hydroxyl groups can provide for tailoring of cellulosic fiber functionality through modifications including acid hydrolysis, grafting, and substitution reactions. Among the various chemical modifications, acid hydrolysis can be used to cleave amorphous regions of cellulose fibers in order to synthesize cellulose nanocrystals (CNC) (Ranby et al., 1949)(Elazzouzi-Hafraoui et al., 2008). Other modifications include etherification which can be carried out in alkali- swollen conditions to obtain block-copolymer substituted products, with regioselective homogenous substitution possible in some solvents (Landoil, 1982)(Heinze & Liebert, 2001). The hydroxyl groups of cellulose can be replaced by carboxylates either selectively or non- selectively depending on the types of reagents selected and the type of hydroxyl group involved (i.e., primary or secondary). Introduction of carboxyl groups can lead to further chemical modifications, such as hydrophobizing, crosslinking, and grafting, to bring additional properties into the fibers. Exemplary chemical modifications of fibers include, but are not limited to, carboxymethylation, periodate-oxidation, and (2, 2,6,6- tetramethylpiperidin-l-yl)oxyl (TEMPO)-mediated oxidations.

Scheme 1 : Potential chemical modifications of cellulosic fibers

Carboxymethyl cellulose (CMC) is one of the most used cellulose ethers because of its hypoallergenic and non-toxic nature. It has high viscosity and high surface charge availability which enhances its water absorbency, thickening properties, and film forming abilities. CMC has wide application in ice creams, toothpaste, detergents, fat free products, textiles, etc. CMC can be prepared both homogenously and heterogeneously by changing solvent systems. A homogenous solvent system, for example water, can be used to generate a more sustainable CMC with a low degree of substitution (DS), while a heterogeneous solvent system, such as a 2 -propanol- water mixture or a benzene-ethanol-water mixture, or homogenous organic solvents, for example butanol, have been mostly used to prepare CMC with higher DS (Zhao et al., 2003)(Moussa et al., 2019). For softwood fibers, a DS of 1.24 has been achieved with the order of preferred substitution as 06 > 02 > 03 and a DS of 2.83 has been achieved by using butanol as a solvent for extensive and longtime treatment of the fig stem cellulosic fibers (Heinze & Pfeiffer, 1999)(Moussa et al., 2019).

CMC can be prepared by reacting cellulose with a carboxymethylating agent, such as chloroacetic acid (i.e., monochloroacetic acid (MCA)). See Scheme 2, below. The preparation of CMC generally involves an alkaline reaction environment to activate cellulose hydroxyl groups and sodium hydroxide (NaOH), or other lye, has typically been used for this purpose. The degree of carboxymethylation and substitution patterns (02 > 06) can be governed by NaOH concentration and increased with an increased amount of NaOH to a certain extent (Heinze & Pfeiffer, 1999). The DS of carboxymethylation can also be increased by increasing the concentration of chloroacetic acid at a set NaOH concentration. For instance, a maximum DS can be reached at a molar ratio of cellulose: MCA = 1: 2.05 (Khullar et al., 2005). Reaction conditions of 55°C and 3 to 4 hours gave maximum DS at a certain chemical concentration regardless of the cellulose sources and solvent systems (Khullar et al., 2005)(Heinze & Pfeiffer, 1999)(Heinze & Koschella, 2005)(Pushpamalar et al., 2006).

Scheme 2: Carboxymethylation of cellulosic fibers

Cellulose owes its structural properties to the fact that it can retain a semi-crystalline state of aggregation even in an aqueous environment, which is unusual for a polysaccharide. In plant cells, it aggregates regularly along the chain, resulting in inter- and intra-molecular hydrogen bonds and hydrophobic interactions, and forms fibrous structures called micro fibrils that, in turn, are composed of elementary fibrils or nanofibrils, which are the basic structural units. Several sources of cellulose have been used to obtain cellulose micro/nanofibers including hardwood, softwood, soybean, cotton, wheat straw, bacterial cellulose, sisal, hemp, sugar bagasse and others. Wood is the most important industrial source of cellulosic fibers. However, obtaining micro fibrillated cellulose from wood is a challenge. Typically, it requires great amount of energy to overcome the extensive and strong inter-fibrillar hydrogen bonds while preserving intramolecular bonds. In other words, the fibrils are desirably processed in such way that micro/nanoscale diameters are achieved while maintaining long axial lengths to attain high aspect ratio. Among the various microfihrillation processes, most are mechanical. For instance, homogenization, microfluidization, use of a super-grinder, grinding, refining, cryocrushing, etc. are mechanical methods.

Generally, in the case of MFC production via simple mechanical approaches, high intensity shear forces are applied to a cellulosic pulp, leading to the individualization of the fibrils. Amongst those mechanical processes, the homogenization is performed under extremely high pressure and is characterized by the relatively large amount of energy used to fibrillate the fibers. In a homogenization process, a cellulose slurry is passed through a very tiny gap between the homogenizing valve and an impact ring, subjecting the fibers to shear and impact forces, which results in cellulose fibrillation. As an alternative for homogenization, micro fluidization can be used to obtain micro/nanofibrils typically characterized by diameters ranging from 20 to 100 nm and several tens of micrometers in length. The micro fluidization comprises passing the cellulose suspension through a thin chamber with a specific geometry, e.g., a Z- or Y-shape, with an orifice width of 100-400 micrometers under high pressure, where strong shear forces and impact of the suspension against the channel walls are produced, resulting in cellulose fibrillation. Although producing a high quality MFC/NFC, both processes face important challenges in order to become economically feasible: the amount of energy used and operational issues such as clogging and industrial scalability.

Ultra-fine friction grinding is another technique used for the production of MFC/NFC. A supermass colloider grinder from Masuko Sangyo Co. Ltd., Japan, is one example commonly used. MFC/CNF can be obtained by passing natural fiber suspensions "n" times through the grinder stones. The shear forces generated from the grinder discs are applied to the fibers leading to cell wall delamination and consequent individualization of the micro/nanofibrils. MFC/NFC are usually obtained with a diameter in the range of 20-90 nm. Alternatively, disc or conical refiners can also be used to produce MFC/NFC through a process that includes both mechanical and hydraulic forces to change the fiber characteristics. Typically, pulp is pumped into the refiners and forced to pass between rotating bars located on a stator and a rotor. Therefore, different types of stress forces are applied to the fiber (crushing, bending, pulling, and pushing) between the refining bars of the fillings. Shear stresses like rolling and twisting occur in the grooves. Other mechanical processes can be used such as ultrasonication, cryocrushing, ball milling, extrusion, aqueous counter and steam explosion.

The presently disclosed subject matter relates, in some aspects, to non-wood fibers, including fiber modifications of non-wood fibers, characterization of the non-wood fibers, generation of MFC from non-wood fiber pulp, and the development of biocomposites from non-wood fibers for application in coatings, films, and composite materials to minimize the usage of synthetic polymers. Among the different non-woody biomass cellulosic fiber sources, hemp and cocoa plants are more generally known for their use in the textile and chocolate industries, respectively. Industrial hemp (Cannabis Sativa L.) is the source of two types of fibers: bast fibers and woody hurds. The bast fibers, typically about 20 weight (wt)% to about 40 wt% of the cellulosic fibers in industrial hemp, are typically present in the outer layer of the hemp stem, while the other about 60 wt% to about 80 wt% of industrial hemp fibers are hemp hurds. (Thygesen et al., 2006) (Sareena et al., 2013). Hemp hurds are from the core part of the hemp stem and are mainly used in animal bedding and hempcrate construction materials. Cocoa pod husk (CPH) is an industrial byproduct of the chocolate industry, and every year millions of tons are thrown away as waste material. The valorization of the waste biomass can significantly contribute to the circular economy, reduce environmental pollution and enhance rural/f aimers income and well-being.

As described hereinbelow, fiber modifications, such as carboxymethylation and oxidation were performed to enhance the swelling properties of non-wood derived cellulosic fibers and to make biocomposites in combination with other cationic polymers for application in coating, composites, and film development. CMC (partially or fully carboxymethylated cellulose) are intrinsically hydrophilic, and their water absorbency can be tailored by varying the DS. Due to the intrinsic hydrophilicity, CMC mobility is restricted once imbedded on a surface. Additionally, due to the presence of negative charge, CMC has an affinity for cationic polymers, such as chitosan and cationic starch.

DAC

Scheme 3 : Periodate oxidation of hemp hurds fibers

The polyhydric structure of cellulose makes it amenable to various oxidizing reagents. For example, the periodate oxidation of cellulose selectively breaks vicinal hydroxyl groups at C2 and C3 in the anhydroglucose (AGU) unit of cellulose, thereby forming a dialdehyde cellulose (DAC) (Coseri et al., 2013). See Scheme 3, above. The oxidation of the AGU unit of cellulose proceeds through formation of a cyclic diester, subsequent cleavage of C-C bonds by a redox reaction, and finally formation of the DAC (Nevell, 1957). Due to the breakdown of cellulose chain, DAC has reduced crystallinity and a lower degree of polymerization. It also generates a higher amount of fines, which can result in lower energy consumption during conversion to MFC. Further oxidation of DAC leads to the formation of acids (Kim & Kuga, 2001), while reaction with an amine by a Schiff base reaction can introduce imine bonds between the amine and cellulose (Wu & Kuga, 2006). According to an aspect of the presently disclosed subject matter, MFC generated from periodate oxidized cellulose can form different composite materials, which can replace and minimize the use of conventional plastic composites.

Scheme 4: Periodate oxidation of carboxymethylated fibers

As described herein, periodate oxidation of CMC was been performed to generate dicarboxymethyl cellulose. See Scheme 4, above. The oxidation of CMC prior to mechanical treatment significantly reduces energy consumption and facilitates nanofibrillation.

Thus, as described herein, fiber modifications, e.g., carboxymethylation, carboxymethylation followed by periodate oxidation, and periodate oxidation of non-wood biomass bring new functionalities to the fibers and enhances fines levels. Reduction in fiber length was confirmed by fiber quality analyzer. The higher level of primary and/or secondary fines reduces energy consumption during MFC production by mechanical treatment. MFC produced from CMC contains a higher number of anionic charges and carboxyl groups, providing better adhesion for polymeric materials in developing biocomposites, while MFC produced from periodate oxidized and periodate oxidized CMC offers energy efficient production of MFC for the development of more hydrophobic composite materials.

Given the low strength and relatively poor barrier properties of paper packaging materials, in some embodiments, the presently disclosed subject matter relates to the development of coatings and films based on the above-described MFC to improve the overall properties of cellulosic paper. Generally, MFC is composed of expanded, high- volume cellulose, which is moderately degraded and greatly expanded in surface area. It can be obtained from the mechanical disintegration of cellulosic materials. MFCs have a long and flexible structure and a large aspect ratio (length/diameter), with lengths in the micro- or millimeter range and widths in the nanometer range, although the aspect ratios of MFCs can vary based on the source of cellulosic material, type, and duration of mechanical treatment (Agate et al., 2020). Currently, bleached wood pulp is considered as the most common raw material for MFC production. However, industrial and agricultural biomass waste, such as rice straw, bagasse, carrot pulp, onion skin, and hemp hurds, can also be used to produce MFC. Out of these materials, hemp is of interest as it is one of the strongest natural fibers. CPH is also of interest to the presently disclosed subject matter given that it can account for as much as 76% of the cocoa pod by weight, but currently does not have significant marketable value.

Despite having advantages, MFC can suffer from its strong hydrophilic characters, which can be an obstacle for its use in composite applications and can result in aggregation due to hydrogen bonding. MFC is also typically relatively inert and not easily subject to chemical manipulation. A further issue is that the generation of MFC can be a time and energy consuming process. As described herein, pretreatments, such as chemical modification of hydroxyl groups can reduce energy consumption. As further described herein, other additives can be used to make MFC based composite films for coating purposes. These additives include, for example, chitosan, glycerol, and cationic starch.

Chitosan, a partial deacetylated derivative of second most abundant natural polysaccharide chitin, is a natural linear polysaccharide consisting of 1,4-linked 2-amino- deoxy-β-d-glucan. It has been reported to have strong antimicrobial and antifungal activities and has been used as a packaging material for the quality of preservation of foods (Jo et al., 2001)(Darmadji et al., 1994)(Kim et al., 2011)(No et al., 2007)(Khan et al., 2012)

Cationic starch is a favorable additive for use in the paper industry because of its renewable and environmentally friendly nature and low cost. It is applied in the paper industry because of its positive charge that has been introduced onto the starch molecule chain and the negative charge sites on the other fillers and can also have strength-enhancing effects on paper (Gulsoy, 2014)(Hamzeh et al., 2013). However, cationic starch can offer some limitations, such as low tensile properties and high-water vapor permeability. It can also has a hydrophilic character, making it hard to control sensibility to moisture content (Vaezi et al., 2019).

The brittleness and hydrophilic behavior of the above-mentioned biopolymers can impact the mechanical, as well as the barrier properties, of food packaging. In some embodiments, these issues can be overcome by adding the plasticizers, like glycerol. Plasticized films can show more flexibility and feasibility than unplasticized films for different packaging applications. For example, although tensile strength decreases, elongation at break can improve with increasing concentration of glycerol (Tarique et al., 2021).

Accordingly, in some embodiments, the presently disclosed subject matter provides an evaluation of the mechanical and barrier properties of agro-based MFC composite films and coating layers from hemp hurds and hemp mix (unmodified, carboxymethylated and periodate oxidized MFC) and from CPH (unmodified and modified) where other additives like chitosan, cationic starch and glycerol as a plasticizer are used. The effect of temperature in the preparation of suspensions for films is described. Moreover, in the case of CPH, the pulp itself has fine contents of around 50% and fiber length (Lw) of around 0.5mm, which is close to MFC. Thus, CPH is evaluated as an alternate to MFC without any mechanical treatment. III. PACKAGING MATERIAL FILMS AND COATING LAYERS

In some embodiments, the presently disclosed subject matter provides a packaging material comprising a film (e.g., a stand-alone film) or a coating layer (e.g., a coating layer for a paper or paperboard material) comprising microfibrillated cellulose (MFC). In some embodiments, the MFC comprises or consists of an agro-based MFC (A-MFC), i.e., a MFC derived from a pulp comprising or consisting of a non-wood lignocellulosic feedstock. In some embodiments, the film or coating layer has (i.e., exhibits) a weight gain of less than about 5% and/or less than about 2.5 g/m² when contacted with hot oil (i.e., oil heated to 65°C) for 20 minutes.

In some embodiments, the A-MFC is derived from a pulp having a primary fines level of more than about 10%. In some embodiments, the pulp has a primary fines level of more than about 15%, more than about 20%, more than about 25%, more than about 30%, more than about 35%, more than about 40%, or more than about 45%. In some embodiments, the pulp has a primary fines level of about 15% to about 50% and/or an average fiber length of about 0.4 millimeter (mm) to about 0.6 mm (i.e., about 0.40, 0.42, 0.44, 0.46, 0.48, 0.50, 0.52, 0.54, 0.56, 0.58, or about 0.60 mm).

The non-wood lignocellulosic feedstock can be any suitable non-wood lignocellulosic feedstock. In some embodiments, the A-MFC is derived in whole or in part from a waste biomass feedstock. For example, in some embodiments, the non-wood lignocellulosic feedstock can be an agricultural residue or other waste product (e.g., a crop residue such as wheat or rice straw or corn stover) or an industrial waste or byproduct derived from an agricultural product (e.g., a lignocellulosic material byproduct produced during the processing of a plant material, such as hemp hurds, cocoa pod husks or bagasse (i.e., sugar cane and/or sorghum bagasse). Accordingly, in some embodiments, the presently disclosed packaging material comprises a film or a coating layer made from alternative (i.e., non-wood) fibers and that can combine recyclability, biodegradability and sustainability.

In some embodiments, the non-wood lignocellulosic feedstock comprises mixtures of different non-wood lignocellulosic feedstocks. In some embodiments, the non-wood lignocellulosic feedstock can be mixed with a wood-based (i.e., a hardwood or softwood feedstock). In some embodiments, at least about 50% (by weight) of the MFC in the film or coating layer is derived from pulp from one or more waste biomass feedstock. In some embodiments, at least about 60% or at least about 70% of the MFC is derived from pulp from a waste biomass. In some embodiments, about 70% to about 100% (e.g., about 70%, about 72%, about 74%, about 76%, about 78%, about 80%, about 82%, about 84%, about 86%, about 88%), about 90%, about 92%, about 94%, about 96%, about 98%, or about 99%) of the MFC is derived from pulp derived from waste biomass. In some embodiments, all of the MFC is derived from waste biomass (i.e., the packaging material is free of any wood- derived papermaking fiber). In some embodiments, the non-wood lignocellulosic feedstock comprises or consists of hemp hurds, a mixture of hemp hurds and hemp bast, bagasse, cocoa pod husks, and combinations thereof.

The pulp used to prepare the MFC can be derived from the feedstock via any suitable pulping method that can breakdown biomass feedstock to provide discrete fibers that can be dispersed in an aqueous solution. In particular, the core fibers of hemp hurds and other hemp waste can be relatively easy to penetrate because of the fineness of the raw materials, which can make it possible to pulp using a variety of methods (Santos et al., 2013). In some embodiments, the pulping method is selected to provide fibers in an desired yield and/or to provide fibers having one or more desirable properties, e.g., a desirable lignin content, length, freeness, brightness, kappa number, etc. In some embodiments, the pulping is performed by a chemical pulping method, such as kraft, sulfite, soda or carbonate pulping. Kraft pulping, which makes up about 80% of pulping in the papermaking industry, comprises digestion of cellulosic or lignocellulosic feedstocks in an aqueous dispersion comprising sodium hydroxide and sodium sulfide, typically at an elevated temperature and/or pressure (Gustafson et al., 1983). Carbonate (Na2CO ) and soda (NaOH, KOH or Ca(OH)2) pulping can be performed at ambient temperature (e.g., about 18°C to about 25°C) or at an elevated temperature (Zhang et al., 2011)(Brodeur et al., 2019)(Yamashita et al., 2010). When performed at an elevated temperature, the pulping time can be reduced. In addition, autohydrolysis, which employs a chemical-free or substantially chemical-free hot water treatment, can be employed. In some embodiments, autohydrolysis can be performed under basic conditions (e.g., to remove pectin). In some embodiments, the pulping can be performed using enzymes (e.g., cellulase). With the exception of kraft pulping, these pulping techniques offer reduced or no emission of sulfur dioxide and odorous gases due to the use of sulfur free chemicals.

Thus, in some embodiments, the pulp comprises kraft fibers, soda fibers (also referred to herein as “alkali fibers”) and/or autohydrolyzed fibers. In some embodiments, the pulp comprises a high yield pulp or a or high lignin-containing pulp. For example, a high lignin-containing pulp can be a pulp comprising more than about 5% lignin, more than about 10% lignin, or more than about 15% lignin. In some embodiments, the high lignincontaining lignin can comprise up to about the same relative amount of lignin as is present in the feedstock used to prepare the pulp. In some embodiments, the pulp comprises fibers all produced by the same pulping method. However, as the pulping method can impart different properties in the papermaking fibers, even among fibers derived from the same feedstock, in some embodiments, the papermaking fibers comprise a mixture of fibers produced by more than one type of pulping method (e.g., a combination of kraft fibers and alkali/soda fibers or a combination of kraft fibers and autohydrolyzed fibers).

In some embodiments, the kraft or soda pulping of the waste biomass can be performed using a reduced amount of chemicals compared to that typically used in the papermaking industry, resulting in pulp that is relatively more sustainable and/or environmentally friendly. For example, in some embodiments, the kraft fibers are pulped using a pulping/cooking mixture comprises less than the usual 18% active alkali. In some embodiments, the kraft fibers are pulped using a pulping/cooking mixture comprising about 12% active alkali. In some embodiments, the alkali/soda pulping comprises a pulping/cooking mixture comprising about 8% alkali metal hydroxide (e.g., about 8% NaOH).

Depending, for example, on the desired end use of the packaging material, in some embodiments, at least a portion of the pulp used to prepare the MFC can comprise bleached and/or refined fibers. As with pulping, in some embodiments, the bleaching can be performed using less than the typical amount of chemicals currently used in the papermaking industry. In some embodiments, the bleaching can be performed using an ECF process involving three steps instead of the more typical five steps or using peroxide only. In some embodiments, the peroxide only bleaching results in a more naturally colored pulp, which can result in a more naturally colored packaging product. In some embodiments, the fibers can be bleached to provide a brighter appearance and/or an appearance more similar to bleached wood-based paper. In some embodiments, the fibers have an International Organization of Standardization (ISO) brightness of at least about 80 (e.g., at least 80, 81, 82, 83, 84, or about 85). In some embodiments, the papermaking fibers have an ISO brightness of about 80 to about 85.

The MFC (e.g., the A-MFC) can be chemically modified or non-chemically modified. For example, in some embodiments, the A-MFC comprises or consists of a modified A-MFC, wherein the modified A-MFC comprises MFC derived from a chemically modified pulp. The chemical modification can involve one or more hydrophobizing, grafting or oxidation reaction known in the paper and/or pulping industry. In some embodiments, the modification comprises carboxymethylation, oxidation or a combination thereof. Thus, in some embodiments, the modified A-MFC comprises or consists of carboxymethylated A-MFC; oxidized A-MFC; carboxymethylated and oxidized A-MFC, or a combination thereof (e.g., can contain A-MFC from two different pulps, one that is carboxymethylated and one that is oxidized or one that is carboxymethylated and one that is both carboxymethylated and oxidized). In some embodiments, the oxidized A-MFC comprises periodate oxidized A-MFC. In some embodiments, the oxidized A-MFC comprises dialdehyde cellulose.

In some embodiments, the film or coating layer prepared from the MFC comprises about 5 weight percent (wt%) to about 90 wt% A-MFC (e.g., about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90 wt% A-MFC). In some embodiments, the film or coating layer comprises about 40 wt% A-MFC to about 80 wt% A-MFC (e.g., 40, 42, 44, 46, 48, 50, 52, 54, 56, 58 or about 60 wt% A-MFC).

In some embodiments, the film or coating layer further comprises one or more additives, e.g., one or more additives known in the papermaking field, such as, but not limited to sizing agents, binders, fillers, wet and/or dry strength agents, retention and drainage aids, optical brighteners (e.g., stilbenes or other fluorescent compounds), plasticizers, cross-linking agents, surface sizing agents, biocides and dyes or other colorants. Sizing agents, for example, can include alkyl ketene dimer (AKD), rosins and rosin derivatives, and alkenyl succinic anhydride. Binders include, but are not limited to, cationic and anionic hydroxyethyl cellulose (EHEC), modified starch (e.g., cationic starch), dextrin, and styrene copolymers such as styrene maleic anhydride copolymer and styrene- acrylate copolymer. Fillers typically used in papermaking include, but are not limited to, calcium carbonate, titanium dioxide, dolomite, clay, and talc. Strength agents include, for example, starches, such as oxidized starch, ethylated starch, enzymatically treated starch, and cationic starches (e.g., starch modified with a quaternary ammonium cation, such as 2,3-epoxypropyl trimethyl ammonium chloride or 3-chloro-2-hydroxypropyl trimethyl ammonium chloride), sodium alginate, gaur gum, proteins, soy lecithin proteins, dextrin, and polyacrylamide. Retention and drainage aids include, but are not limited to, calcium carbonate and polyethyleneimine. Cross-linking agents include, but are not limited to, polycarboxylic acids, such as acrylic, maleic, polymaleic, succinic, polyitaconic and citric acids. Plasticizing agents include bio-based plasticizers (e.g., citrate esters such as triethyl citrate (TEC), acetyl triethyl citrate (ATEC), acetyl triethyl citrate (ATEC), tributyl citrate (TBC), acetyl tributyl citrate (ATBC), trioctyl citrate (TOC), butyryl trihexyl citrate (BTHC), trihexyl o-butyryl citrate and trimethyl citrate (TMC)), dicarboxylic/tricarboxylic ester- based plasticizers, adipates-based plasticizers, sebacates-based plasticizers, and/or maleates-based plasticizers, as well as glycerol, glycerol triacetate, tributyl citrate, polyethylene glycol, and the like. In some embodiments, the additive can include a polyhydroxyalkanoate (PHA), such as, but not limited to poly-3 -hydroxy valerate (PHV) or poly-4-hydroxybutyrate (P4HB). Representative amounts for such additives can be in the range of about 0.5% by weight to about 30% by weight of the film or coating layer, for example. In some embodiments, the film or coating layer comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a PHA, and AKD. In some embodiments, the film or coating layer can comprise about 15 wt% to about 25 wt% chitosan (e.g., about 15, 20 or 25 wt% chitosan). In some embodiments, the film or coating layer can comprise about 15 wt% to about 25 wt% cationic starch (e.g., about 15, 20, or about 25 wt% cationic starch). In some embodiments, the film or coating layer comprises about 0.5 wt% to about 5 wt% glycerol (e.g., about 0.5, 1, 2, 3, 4, or 5 wt% glycerol). In some embodiments, the film or coating layer comprises about 0.5 wt% to about 5 wt% AKD (e.g., about 0.5, 1, 2, 3, 4, or about 5 wt% AKD).

As noted above, in some embodiments, the pulp used to prepare the MFC has a primary fines level (or a primary and/or secondary fines level) of over 10 % (e.g., about 15%, 20%, 25%, 30%, 35%, 40%, 45%, or about 50%). In some embodiments, the chemical modification and/or fibrillation can increase the fines levels and/or decrease the average fiber length. Thus, in some embodiments, the MFC (e.g., the A-MFC) has a total fines level (e.g., a combination of primary and secondary fines) of about 50% to about 95% (e.g., about 50, 55, 60, 65, 70, 75, 80, 85, 90, or about 95% fines). In some embodiments, the MFC (e.g., the A-MFC) has an average fiber length of about 0.1 mm to about 0.45 mm (e.g., about 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, or about 0.45 mm).

Films and coating layers of the presently disclosed subject matter can have any desirable thickness. In some embodiments, the film or coating layer can have a thickness of about 1 micrometers (mm) to about 200 mm (e.g., about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, or about 200 mm). In some embodiments, the presently disclosed coating layers have a thickness of about 1 mm to about 30 mm. In some embodiments, the presently disclosed films have a thickness of about 10 mm to about 200 mm. In some embodiments, the film or coating layer has a thickness of about 20 mm to about 140 mm. In some embodiments, the film or coating layer has a bulk of about 0.5 cubic centimeters per gram (cm³/g) to about 3.5 cm³/g to about 2.0 cm³/g. In some embodiments, the film or coating layer has a bulk of about 0.5 cm³/g to about 2.0 cm³/g (e.g., about 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or about 2.0 cm³/g).

The films or coating layers of the presently disclosed subject matter can have one or more desirable barrier characteristics (e.g., for use in food and/or beverage packaging). In some embodiments, the film or coating layer has a desirable level of resistance to oil, water vapor, or another gas. For example, as noted hereinabove, in some embodiments, the film or coating layer has (i.e., exhibits) a weight gain of less than about 5 % and/or less than about 2.5 g/m² when contacted with hot oil (i.e., oil heated to 65 °C) for 20 minutes. In some embodiments, the film or coating layer has a weight gain of less than about 2% (e.g., less than about 2.0, 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1., or about 1%) when contacted with hot oil for 20 minutes. In some embodiments, the film or coating layer has a weight gain of less than about 1.19 g/m² (e.g., less than about 1.19, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.1, 1.0, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, or about 0.1 g/m²) when contacted with hot oil for 20 minutes. In some embodiments, the film or coating layer has a weight gain of less than about 3% when contacted with room temperature oil for 15 hours. In some embodiments, the film or coating layer has a weight gain of about 1% to about 2.5% (e.g., about 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, or about 2.5%) when contacted with room temperature oil for 15 hours. In some embodiments, the film or coating layer has a weight gain of less than about 1.8 g/m² (e.g., when the film or coating layer as a weight of about 60 gsm) when contacted with room temperature oil for 15 hours. In some embodiments, the film or coating layer has a water vapor transmission rate (WVTR) of less than 50 grams per square meter millimeter per day (g/m².mm/day). In some embodiments, the film or coating layer has a WVTR of less than about 45 g/m².mm/day, less than about 40 g/m².mm /day, less than about 35 g/m².mm /day, less than about 30 g/m².mm /day, less than about 25 g/m².mm /day, less than about 20 g/m².mm /day, or less than 15 g/m².mm /day. In some embodiments, the film or coating layer has a density of about 0.3 grams per cubic centimeter (g/cm³) to about 2.1 g/cm³ (e.g., about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or about 2.1 g/cm³). Films with lower WVTRs can be prepared by preparing a film with a higher density.

In some embodiments, the film or coating layer can have one or more desirable mechanical properties. In some embodiments, the film or coating layer has a tensile index of about 30 Newton meter per gram (Nm/g) or more. In some embodiments, the tensile index is about 30 Nm/g to about 300 Nm/g (e.g., about 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, or about 300 Nm/g). In some embodiments, the film or coating layer has a stretch of about 1.5% or higher. In some embodiments, the film or coating layer has a stretch of about 1.5% to about 10% (e.g., about 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, or about 10%). In some embodiments, the film or coating layer has a stretch of about 3% to about 8% or about 4% to about 8%.

The films and coating layers of the presently disclosed subject matter can be used for any packaging material, e.g., for packaging materials where it can be desirable to provide a barrier to oil, water or gases, as well as to packaging materials where more sustainable and/or biodegradable materials would be of interest. Thus, the packaging materials can be used for food and/or beverage packaging, pharmaceutical packaging, electronics packaging, personal care and/or cosmetics packaging, and/or for packaging of single-use items (disposable utensils, certain medical supplies, such as single use syringes, etc.).

In some embodiments, the packaging material is a food or beverage packaging material. Thus, for example, the packaging material can be a food packaging that comprises or consists of a film of the presently disclosed subject matter or be a food or beverage packaging material coated (on a surface intended to come into contact with a food or beverage, on a surface intended to come into contact with an external environment (e.g, air), or on both such surfaces) with a coating layer or film of the presently disclosed subject matter. Thus, in some embodiments, the packaging material comprises a substrate, wherein said substrate is coated on at least one surface by the film or coating layer comprising A- MFC. In some embodiments, the substrate is a flexible substrate. In some embodiments, the substrate comprises paper or another biodegradable and/or sustainable material. In some embodiments, the paper or other substrate comprises or consists of fibers (e.g., papermaking fibers) derived from a waste biomass. Thus, in some embodiments, the packaging material can comprise greater than 50%, 60%, 70%, 80%, 90%, 95%, or more sustainable and/or recyclable material, such as material derived from waste biomass. In some embodiments, the packaging material comprises 100% biodegradable and/or recyclable materials.

The food packaging material can be provided in any desirable form, for example, as a coated sheet (e.g., butcher paper) to wrap food items or as coated bag or other container for food, e.g., a box, a carton, a tray, a plate, a bowl, a cup, a lid for a cup or other container, a take-out container, a clamshell container. In some embodiments, the food packaging material can be a packaging material for food for humans. In some embodiments, the food packaging material can be used as a flexible flow wrap for confectionery products such as, but not limited to, chocolate candy bars, gum, mints, fruity confections, and sugar-coated candies. In some embodiments, the food packaging material can be a packaging material for food for pets or other animals (e.g., in farms or zoos), such as a packaging material for pet treats. In some embodiments, the food packaging material can be used to provide at least one component of a food packaging item also including one or more additional materials (e.g., a plastic or metal foil component).

In some embodiments, the presently disclosed subject matter provides a method for preparing a film (i.e., a film having a weight gain of less than about 5% and/or less than about 2.5 g/m² when contacted with hot oil (i.e., oil heated to 65°C) for 20 minutes) comprising A-MFC (e.g., where the film can be used as a stand-alone film or be used as a coating layer on a substrate, such as a paper-based substrate). In some embodiments, the method comprises: (a) preparing a suspension comprising A-MFC (i.e., wherein said A- MFC is MFC prepared from a pulp from a non-wood lignocellulosic feedstock, optionally wherein said pulp has a primary fines level of more than about 10% or wherein said pulp has a high level (e.g., greater than about 40%, 45%, or 50%) of primary and/or secondary fines); (b) forming a web using from the suspension; and (c) drying the web, thereby providing the film.

The A-MFC can be MFC from any suitable non-wood lignocellulosic feedstock as described above. Thus, in some embodiments, the non-wood lignocellulosic feedstock comprises one or more agricultural residue and/or industrial by-product. In some embodiments, the non-wood lignocellulosic feedstock comprises hemp hurds, a mixture of hemp hurds and hemp bast, cocoa pod husks, or a combination thereof.

In some embodiments, preparing the suspension comprising A-MFC comprises fibrillating a suspension of pulp from a non-wood lignocellulosic feedstock, wherein said pulp has a primary fines level of more than 10%. In some embodiments, the pulp has a primary fines level of about 15 % to about 50% (e.g., about 15%, 20%, 25%, 30%, 35%, 40%, 45%, or about 50%).

The pulp can be pulped by any suitable means and be bleached or unbleached. In some embodiments, the pulp is a kraft pulp, an autohydrolyzed pulp, an unbleached pulp, a higher yield pulp, and/or a higher lignin-containing pulp. In some embodiments, some or all of the pulp is chemically modified (e.g., carboxymethylated) prior to or after fibrillation. In some embodiments, some or all of the pulp is chemically modified prior to fibrillation. In some embodiments, the chemical modification can comprise carboxymethylating the pulp, oxidizing the pulp, or carboxymethylating and oxidizing the pulp. In some embodiments, the oxidizing is periodate oxidizing. Chemical modification can increase the total level of fines in the pulp prior to fibrillation. In some embodiments, chemical modification can decrease the amount of energy used in fibrillating the pulp. In some embodiments, increasing the degree of substitution of the modified pulp (i.e., the average DS of the modified fibers in the pulp) can decrease the amount of energy used in fibrillating the pulp. In some embodiments, the DS is less that about 1.2. In some embodiments, the DS is about 0.8 to about 1 .2. In some embodiments, the use of a pulp derived or at least partially derived from CPH can decrease the amount of energy used in fibrillating the pulp. In some embodiments, the amount of energy used to fibrillate the fibers is less than about 5000 kilowatt-hours per ton (KWH/T). In some embodiments, the energy used to fibrillate the fibers is less than about 4500 KWH/T, less than about 4000 KWH/T, less than about 3500 KWH/T, less than about 3000 KWH/T, less than about 2500 KWH/T, less than about 2000 KWH/T, less than about 1500 KWH/T, or less than about 1000 KWH/T.

Carboxymethylation can be performed in an aqueous medium, instead of using traditional organic solvents. For example, carboxymethylation can be performed by preparing a fiber slurry (e.g., about 4% fiber) and a carboxymethylating agent, such as a haloacetic acid (e.g., chloroacetic acid or a salt thereof) and stirring the reaction mixture at an elevated temperature (e.g., about 60°C) for a few hours (e.g., about 4 hours) (Chang et al., 2010). Aqueous alkali (e.g., NaOH or KOH) can be added and the resulting mixture maintained for a period of time (8 to 14 hours) at a suitable temperature (e.g., room temperature to about 70°C. Then the carboxymethylated fiber can be isolated and washed with ethanol and/or water. The amount of carboxymethylating agent used can be between about 0.5 moles to about 20 moles per anhydrous glucose residue in the fiber. Higher levels of substitution (higher DS) can be achieved using higher amounts of the carboxymethylating agent. Periodate oxidation can be performed for example, by preparing a 4% fiber slurry with sodium periodate (NalC ). (Chang et al., 2010). The reaction mixture can be heated (e.g., to about 55°C) and shaken or stirred for a period of time (e.g., about 2 hours).

In some embodiments, preparing the suspension comprising A-MFC comprises contacting the A-MFC with a liquid to provide a suspension comprising a total solids content (i.e., a total dry component content) comprising at least about 50 weight percent (wt%) A- MFC. In some embodiments, the liquid is water. In some embodiments, the total solids content comprises about 50 wt% to about 80 wt% A-MFC (i.e., of the solids in the suspension, about 50 wt% to about 80 wt%, i.e., 50%, 55%, 60%, 65%, 70%, 75%, or about 80%, is A-MFC). In some embodiments, the suspension as a whole comprises a solids content of about 5% or less. In some embodiments, the suspension as a whole comprises a solids content of about 2.0% or more. In some embodiments, the solids content is between about 2.0 and about 2.5% of the suspension.

In addition to A-MFC, the solids in the suspension can further comprise one or more additives. Thus, in some embodiments, the suspension further comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a PHA, and AKD. For example, in some embodiments, the solids content comprises about 15 wt% to about 25 wt% chitosan or cationic starch (e.g., about 20 wt% chitosan or about 20 wt% cationic starch). In some embodiments, the solids content comprises about 1 wt% to about 5 wt% glycerol. In some embodiments, the solids content comprises about 1 wt% to about 5 wt% AKD.

In some embodiments, the temperature used in preparing the suspension can affect the properties of the film or coating layer prepared from the suspension. In some embodiments, the preparing the suspension comprises mixing the suspension (e.g., stirring or shaking the suspension) at a temperature between about room temperature and about 80 C for a period of time. In some embodiments, the temperature is about 18°C to about 25°C. In some embodiments the temperature is about 30°C, about 35°C, about 40°C, about 45°C, about 50°C, about 55°C, about 60°C, about 65°C, about 70°C, about 75°C, or about 80°C. In some embodiments, the temperature is about 80°C. In some embodiments, the mixing is performed from about 15 minutes to about 2 hours (e.g., 15, 30, 45, 60, 75, 90, 105, or about 120 minutes). In some embodiments, the mixing is performed for about 30 minutes.

In some embodiments, step (b) comprises casting a web or applying the suspension to a surface of a substrate. In some embodiments, step (b) comprises casting a web, drying the web (e.g., in air or an oven) to form a film and then applying the web to a surface of a substrate to provide a coated substrate. In some embodiments, the substrate is a paper substrate or other material prepared from a biodegradable and/or sustainable material. In some embodiments, the method further comprises forming a packaging material from the film or from the coated substrate. Forming the packaging material can include one or more of converting technique used in packaging, such as, calendaring, coating, printing, embossing, slitting, sheeting, folding, creasing, wrapping, gluing (sealing), laminating, and the like. Several methods are known for all mentioned converting techniques. For example, in some embodiments, calendering can include supercalender, hardnip calender or hotsoft nip calender. In some embodiments, the printing methods can include, but are not limited to, flexography, rotogravure, offset lithography, inkjet, or electrophotographic printing, etc. In some embodiments, the sealing operations can encompass use of cold seal or heat-sealing agents. In some embodiments, the wrapping operation can comprise use of a horizontal form fill seal machine (HFFS) or a vertical form fill seal machine (VFFS), depending on the wrapping needs.

In some embodiments, the packaging materials of the presently disclosed subject matter can have the same or similar look and/or feel as packaging materials prepared from conventional packaging materials and/or wood-based paper packaging materials.

EXAMPLES

The following Examples are included to further illustrate various embodiments of the presently disclosed subject matter. However, those of ordinary skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the presently disclosed subject matter.

EXAMPLE 1

Chemical Modifications

Materials:

Bleached hemp hurds (from the Netherlands) and cocoa pod husk (from South America) were processed by disc refining, while hemp mix (from the United States of America) refined by valley beating. Southern bleached hardwood and softwood was used after refining. All chemicals used in fiber modifications (0.68M and 1.03M chloroacetic acid sodium salt (CMA), 1.25M NaOH, reagent alcohol, 0.16M NalOr) and characterizations (0.1M NaOH, 0.1M HC1, 70% methanol, and NH2OH.HCI, cupriethylenediamine) were procured from Fisher Scientific (Hampton, New Hampshire, United States of America) and used as is.

All the chemical modification reactions were carried out with unrefined hemp hurds, hemp mix (valley beating), cocoa pod husks, and refined hardwood (2500 PFI refined). For simplicity, the following sample IDs are used herein: HH-NL (hemp hurds, the Netherlands) HM-US (hemp mix, United States of America), CPH (cocoa pod husk), HW (hardwood), SW (softwood), CM (carboxy methylation), PI (periodate oxidation), CMPI (carboxymethylation followed by periodate oxidation), MFC (microfibrillated cellulose), CM-HH-MFC (microfibrillated carboxymethyl hemp hurds), CM-HM-MFC (microfibrillated carboxymethyl hemp mix), CM-HW-MFC (microfibrillated carboxymethyl hardwood), CMPI-HH-MFC (microfibrillated carboxymethyl -periodate oxidized hemp hurds), and PI-HH-MFC (microfibrillated periodate oxidized hemp hurds). Carboxymethylation to prepare carboxymethylated cellulose ( CMC)

Carboxymethylation of hemp hurds, hemp mix, cocoa pod husk, and hardwood fibers was carried out using a green solvent as the reaction media using a modified process based on a method previously described in the literature (Sim, 2015). The reaction conditions were kept similar for all the fibers to compare results of modified fibers and the biocomposites made out of the modified fibers, MFC, and the corresponding biopolymers. A 4% fiber slurry with 0.68M CMA was prepared using de-ionized (DI) water as a green solvent. The reaction was carried out for 4 hours at 60°C in a mechanical shaker. After 4 hours, 100 mL of 1.5M NaOH solution was added into the pulp slurry and the pulp containing flask was left overnight at room temperature. On the following day, the pulp was washed with 70% ethanol followed by DI water to remove unreacted CMA and any contaminants in the modified fibers. Carboxymethylation was performed on a second batch of hemp hurds using a higher concentration of CMC (1.05M) while keeping all the other conditions similar to prepare a higher degree of substitution (DS) carboxymethylated hemp hurds fiber.

Periodate oxidation to prepare dialdehyde cellulose (DAC)

Periodate oxidation of the wood and non-wood fibers was performed based on a method previously described in the literature (Chinga-Carrasco & Syverud, 2014) updated according to laboratory requirements. 50.0 g of OD mass (oven dried) hemp hurds fiber was suspended into DI water having consistency of 4% cellulose and 0.16M NaIO4 in a 2L flask. The flask was covered with an aluminum foil to prevent the photo-induced decomposition of periodate and reaction was performed at 55 °C for 2 hours in a mechanical shaker. After 2 hours, the product was filtered and washed several times with DI water to remove iodine- containing compounds and unreacted reagents.

Carboxymethylation followed by periodate oxidation (CMP1)

This modification of fibers was performed to produce carboxy methylated dialdehyde cellulose. First, carboxymethylation of the fibers was performed as described above and then carboxymethylated fibers were further reacted with NaIO₄ to generate carboxymethylated dialdehyde cellulose.

A summary of different fiber modifications and the conditions used for the modifications is shown in Table 1, below. Table 1: Different types of fiber modifications and their conditions

EXAMPLE 2

Preparation of microfibrillated cellulose (MFC)

MFC from modified and unmodified hemp, cocoa pod husk and hardwood fibers was prepared using a top-down approach (Chauhan & Chakrabarti, 2012). A suspension of 3 wt.-% of HH, HM, CPH, HW, CM-HH, CM-HM, CM-HW and 4wt-% of PLHH and CMPLHH was prepared using a Lightning mixer for 15 minutes to obtain a consistent fiber suspension. The suspension of pulp was then passed through the Masuko Super Mass collider (Masuko Sangyo Co. Ltd., Japan) with silicon carbonate grinding stones (E6-46 DD) at 2400 rpm for further fibrillation. See Figure 1. The clearance between the upper and lower grinder was kept negative as the pulp was being passed through them. The samples were collected after fibrillating at different cumulative energies. Three MFC samples from each of the pulp suspensions were taken and dried using an IR solid analyzer to obtain the solids content and averaged to find the mean solids content value.

EXAMPLE 3

Fiber, Modified Fiber, and MFC Characterization

Fourier Transform Infrared Spectroscopy (FT1R):

A PerkinElmer SPECTRUM™ spectrometer (PerkinElmer Corporation, Waltham, Massachusetts, United States of America) as used to record the FTIR spectra of the modified and unmodified fibers. Each sample was brought into the diamond crystal of an attenuated total reflectance (ATR) and the contact area of the ATR was a circle of ~1.5 mm in diameter. The oven-dried samples were brought into contact with the area to be analyzed. All spectra were collected between 4000 and 500 cm^-1 with a 20 scans per sample and a resolution of 4 cm^-1. For comparison of the data, baseline correction was performed, and all the spectrum was collected at the same baseline.

Microscopy:

A Hitachi S-3200N variable pressure scanning electron microscope (VPSEM; Hitachi, Tokyo, Japan) was used to characterize the morphology of unmodified and modified MFC. Each sample was sputter coated with AuPd for 5 minutes before being visualized at 2 kV under identical magnification conditions. SEM images were taken at three different magnifications: 500 times (500x), 1000 times (lOOOx), and 5000 times (5000x). Transmission electron microscope (TEM) images were also taken at 5000x of each sample.

Determination of Degree of substitution (DS) of carboxymethylation:

The degree of substitution (DS) of carboxymethylation of hemp hurds, hemp mix and hardwood fiber was measured according to a modified Na Wu method ((Wu et al., 2018). According to the method, 1.0g of oven dried carboxymethylated cellulose samples was taken into a 250.0 mL Erlenmeyer flask. Then, 8.0 mL of 70.0% methanol added into the flask and leave it for 2-3 minutes. After 2-3 minutes, 100 mL of deionized water was added and stirred with a magnetic stirrer for 2 hours. Two drops of methyl orange were added and the mixture was titrated against 0.1N HC1 solution. The DS was calculated according to the following formula: where 0.162 is the molar mass of an anhydroglucose unit, g/mmol; 0.058 is the net increase in the mass of an AGU for each carboxymethyl group substituted, g/mmol; X is the carboxyl content per gram of sample, mmol/g; N is the total carboxyl content of the sample, mmol; and m is the absolute dry mass of the sample, g.

Fiber Quality Analysis ( FQA ):

A high-resolution fiber quality analyzer (HiRes FQA, OpTest Equipment Inc, Hawkesbury, Ontario, Canada) was used to determine fiber length (l_w), fine levels and other physical properties of the different pulp samples. Before running the equipment, FQA was calibrated according to the manufacturer’s guideline and a laboratory disintegrator was used to disintegrate the fibers. The FQA was determined for unmodified, modified and microfibrillated cellulose (MFC).

Degree of Polymerization (DP):

The average degree of polymerization of modified and unmodified MFC (average DPv) was determined according to the standard viscometric methods (CM-15:88, 1998)( Moutou et al., 2004) using a glass capillary viscosimeter (Schott and Gen, Mainz, Germany) and fresh CED solvent (Carlo Erba Reagents S.r.l., Milan, Italy). Twenty-five milligrams of oven dried MFC sample was dissolved in 50 mL of solution, consisting of 25 mL cupriethylenediamine (CED) and 25 mL deionized water. The efflux time of a solution was measured in duplicates. The Mark-Houwink-Sakurada equation was used to calculate average DPv (Evans & Wallis, 1989).

Charge Measurement:

The total charge content on the surface of the fibers was measured using the colloidal titration method (Tyagi et al., 2019). Polyelectrolyte titration was carried out to identify the sign and magnitude of ionic charge present on the fiber surface using the streaming current method for determination of the endpoint. To determine the net charge, both the unbleached and bleached fiber samples were disintegrated into pulp at a 0.075% solid consistency in deionized water. The colloidal charge of 200 ml of pulp suspensions was evaluated by titration using a Chemtrac EC A 2000 P streaming current potential (Chemtrac Inc., Norcross, Georgia, United States of America). The endpoint for charge neutralization of fibers was determined by the addition of a cationic polymer, i.e., (poly (diallyldimethylammonium chloride) (poly DADMAC).

Total Carboxyl Content Analysis:

The total carboxyl content of the different fibers was measured by an acid-base titration method (Ghorpade et al., 2017) (Mali et al., 2018). Briefly, 100 mg of oven-dried pulp was dissolved in 20 mL 0.1 N NaOH and stirred with a magnetic stirrer for 2 h. An excess amount of 0.1N NaOH was titrated with 0.1 N HC1 using phenolphthalein as an indicator. The total carboxyl content in milliequivalents per 100 g of pulp slurry was calculated based on the following formula:

Carboxyl content = (V_b-V_a) x N x 100/W where, V_b and V_a are the volumes of HCL in the absence and presence of pulp sample, respectively; N is the normality of HC1; and W is the weight of sample (g).

EXAMPLE 4

Discussion of Examples 1-3

The physical, chemical and morphological characteristics of the chemically modified fibers were analyzed using various techniques. For example, non-wood fiber (e.g., hemp hurds, hemp mix, and cocoa pod husk fiber) modification and MFC generation at different energy consumptions were studies as part of the development of biocomposites for advanced application in coatings and films development. The energy consumption, fines level, charge analysis, carboxyl content and degree of substitution at different steps of modification and after MFC production was been studied. Hardwood (HW) fiber modification and production of MFC was also studied to provide a reference sample to compare wood fiber and non-wood biomass in composites development.

FTIR analysis:

Figures 2A and 2B show the FTIR spectra of modified and unmodified fibers. The appearance of stretch in the region of 1030-1170 cm^-1 is believed to be due to the presence of C-O-C vibrations of primary and secondary hydroxide groups of the carbohydrates (Guimaraes et al., 2009). The peaks at 1281, 1370 and 1427 cm^-1 are believed to be mostly attributable to the presence of aromatic esters, ether and phenol compounds (Tanpichai et al., 2019).

The peak at 1650 cm^-1 in the PI, CMPI and CM modified cellulose indicates the presence of C=O stretching of carboxyl and ketone groups (Pelissari et al., 2014). There was a sharp peak in the periodate and carboxymethylated-periodate oxidized fibers due to the presence of DAC and a relatively weak stretch in the carboxymethylated fibers because of the presence of C=O group in the CMC modified fibers. The presence of this kind of stretching vibrations in the unmodified fibers is absent, which suggests successful incorporation of carboxymethyl group and dialdehyde functional groups in the modified fibers. The hemp hurds (HH), hemp mix (HM) and hardwood (HW) all showed a similar trend of stretching vibrations. The peak corresponding to 2900 cm^-1 due to the symmetric and asymmetric C-H stretching and peak at 3400 cm^-1 is characteristic for the OH stretching of cellulose (Tanpichai et al., 2019).

Degree of substitutions (DS) for carboxymethylation: The DS of carboxymethyl cellulose has direct impact on the viscosity, emulsibility, stability, solubility, stability, acid resistance and energy consumption of producing MFC from carboxymethylated fibers. The DS of carboxymethylation for hemp biomass and hardwood fibers are showing in Figure 3. It has been observed that the DS of hemp mix is highest followed by hemp hurds and is lowest for hardwood when all the samples treated using the same conditions and chemical environment. A higher DS sample of hemp hurds was obtained by enhancing the amount of treated chemicals (monochloroacetic acid of sodium salt). These DS values have a direct correlation in the generation MFC by mechanical treatment. Figure 4 shows that unmodified hemp hurds and carboxymethylated hardwood consume the highest amount of energy for microfibrillation and generation of MFC.

Energy consumption and fines level:

The cumulative energy consumption for the production of microfibrillated cellulose from different fibers significantly varies depending on the primary fines level, fiber types, fiber modifications and degree of substitutions. It has been observed that among the various untreated fibers, CPH has the highest number of primary fines followed by hemp hurds and softwood has the lowest number of primary fines. From the energy consumption diagram in Figure 5, it can be observed that CPH consumes the lowest energy for the preparation of MFC, while unmodified hardwood fibers consume the highest level of energy. The fines of hemp hurds increased after fiber modifications, which also helps to reduce the energy consumption while making MFC. On the other hand, periodate oxidized fibers consume the lowest energy among the various modified fibers due to the low DP of periodate oxidized cellulose. The carboxymethylated cellulose of hardwood consumes the highest energy compared to the carboxymethylated hemp hurds and hemp mix. It has also shown that fibers with a higher DS of carboxymethylation consume less energy for higher fibrillation.

There is a direct correlation observed for fiber length with fiber modifications and generation of MFC through mechanical grinding. The fiber length decreases with fiber modifications and mechanical grinding for all types of fibers, chemical modifications and mechanical treatment. See Figure 6. The fines level also increases after fiber modifications and mechanical treatment.

Among the various modifications, it was observed that carboxymethylation of hemp fibers generates higher fines level than periodate oxidation. Without being bound to any one theory, this is believed to be due to the longer treatment time associated with carboxymethylation compared to periodate oxidation. It was also observed that the CPH- MFC has a lower fiber length than any other unmodified or modified fibers. The fiber lengths and number of fines content before mechanical grinding supports energy consumptions, as longer and unmodified fibers consume a higher amount of energy for micro fibrillation.

Degree of polymerization:

The degree of polymerization (DP) in the cellulosic fibers was calculated indirectly by measuring the viscosity of unmodified and modified MFC. Higher viscosity indicates a higher average DP that in turn indicates a stronger bond in the pulp. Figure 7 shows the DP of MFC prepared from carboxymethylated cellulose, periodate oxidized cellulsoe, and carboxymethylated-periodate oxidized cellulose. CMPI-modified MFC and Pi-modified MFC had lower DP due to the breakdown of the AUG unit of the cellulose chains and formation of dialdehyde groups. The cleavage of cellulose chains reduces fiber length and increases the fines content. On the other hand, carboxymethylated only-modified MFC had the highest DP as carboxymethylation does not break cellulose chain.

Surface charge and carboxyl content:

Surface charge is an important parameter for papermaking, playing a role through electronic interactions of the charged soluble and particulate interaction (Lyytikainen et al., 2011). Surface charge also affects the swelling ability of cellulose fibers and provides a driving force for the adsorption of sizing agents, retention aids and strength enhancing agents (Dang et al., 2007). It also affects the post-processing of fibers, such enzymatic treatment and composites developments (Zhang et al., 2016). Figure 8 shows the anionic charge of various modified and unmodified MFC samples. From the figure, it is clear that the carboxymethylated non-wood fibers (e.g., hemp hurds and hemp mix) had the highest amount of negative charge while commercial grade MFC had the lowest. As carboxymethylation contributes to enhance the anionic charge of the fibers, it has also been observed that a higher DS of the carboxymethylation contributes higher negative charge. The presence of the anionic charge is useful in the preparation of biocomposites of MFC by enhancing the combination of the MFC with other polymers. On the other hand, the amount of carboxyl groups shows a similar trend to surface charge. The carboxymethylation of hemp biomass contributes to increase the amount of carboxyl groups (see Figure 9) while periodate oxidation shows little or no effect in terms of enhancing the amount of carboxyl groups in the modified fibers. The higher DS hemp hurds sample resulted in an increased amount of carboxyl groups in the fibers compared to the lower DS hemp hurds fibers. The relatively higher number of surface charge in carboxymethylated fibers was due to the higher number of carboxyl groups, fatty acids, hemicellulose and lignin’s phenolic groups (Sjostrom, 1989).

The presence of a higher number of anionic charges and carboxyl groups facilitates better entanglement by providing hydrogen bonding, which can help to increase burst and tensile strength of the fibers (Belle & Odermatt, 2016). Carboxyl groups can also act as binding sites to enable controlled chemical loading and releasing by regulating the interactions between the chemicals and carboxyl groups (Ghorpade et al., 2017).

Morphology:

Scanning electron microscope (SEM) images of MFC from modified and unmodified hemp hurds are shown in Figure 10. Transmission electron microscope (TEM) images are shown in Figure 11. From the SEM images, it was observed that the MFC fibers were highly fibrillated and dispersed, a positive indication of the quality of the MFC. Both the modified and unmodified MFC were well dispersed and formed a film-like structure, indicating the suitability of the MFC for use in high-barrier flexible films and coatings, e.g., paper coatings, such as for use in food packaging to replace single-use plastic -based materials. The TEM images showed further details of fiber morphology, such as the flattened nature of the modified and unmodified MFC. The carboxymethylated hemp hurds MFC was highly fibrillated and forms a film. The periodate-modified hemp hurds MFC showed some nanoparticle-like material distributed along the flattened fibers. All the MFC formed a transparent film, again indicating suitability for use in high-barrier flexible packaging.

In summary, renewable and biodegradable microfibrillated cellulose fibers were prepared to achieve low-cost, functional composites with improved properties for advance applications in packaging and other fields. To enhance the interaction between hydrophilic fiber surface and a polymer matrix, mild surface modifications of fibers were performed under aqueous conditions to add different functional groups to the fibers. Carboxymethylation, periodate oxidation, and carboxymethylation followed by periodate oxidation were performed to add new functional groups on the fiber surfaces for better adhesion to polymer matrix. Successful fiber modification was confirmed by FTIR. The presence of the carboxymethyl and dialdehyde groups was observed in the CMC and periodate oxidized fibers, respectively. Carboxymethylation of the fibers significantly enhanced the carboxyl content and anionic charge content. A higher DS contributed to a greater amount of anionic charge and carboxyl content, which enhances adhesion and binding affinity for polymeric materials. On the other hand, periodate oxidation of hemp biomass generated dialdehyde cellulose which has lower degree of polymerization but consumes significantly less energy for microfibrillation. It was also observed that fiber modifications helped to increase fines content and reduce fiber length. The higher amount of fines and reduced length can lead to reduced energy consumption during mechanical treatment to generate microfibrillated cellulose. Morphological studies performed via TEM and SEM showed that MFC (e.g., from hemp hurds) was able to form transparent film- like structures, indicating suitability for use in high-barrier packaging. The low-cost generation of MFC from non-wood biomass helps to valorize the waste biomass and potentially reduce the utilization of conventional wood fibers. The biocomposites developed from these alternative materials can be cost effective and have improved properties, which can enhance the barrier properties of paper and packaging materials.

EXAMPLE 5

Preparation of Composites

Materials:

Hemp hurds (HH), hemp mix (HM), auto hydrolyzed hemp hurds (AH-HH), cocoa pod husk (CPH), and unbleached cocoa pod husk (UCPH) were used for the preparation of microfibrillated cellulose (MFC). For modified MFC, the pulp fibers were modified first by carrying out following chemical modifications: carboxymethylation (CM) (Sim, 2015); periodate oxidation (PI) (Coseri et al., 2013); and carboxymethylation followed by periodate oxidation (CMPI). Other biopolymers being used to make the composites included: chitosan (medium MW), cationic starch, and glycerol (99%). Chitosan was purchased from Thermo Fisher Scientific (Waltham, Massachusetts, United States of America) in powdered form. Cationic starch (Cato 237) was provided by Ingredion (Westchester, Illinois, United States of America) in powdered form.

Briefly, MFC from modified and unmodified hemp hurds, hemp mix, and cocoa pod husk fibers was prepared using a top-down approach (Chauhan & Chakrabarti, 2012). A suspension of 3- 4wt-% of MFC from each sample was prepared using a Lightning mixer for 15 minutes to obtain a consistent fiber suspension. The suspension of pulp was then passed through a Masuko Super Mass collider (Masuko Sangyo Co. Ltd., Japan) with silicon carbonate grinding stones (E6-46 DD) at 2400 rpm for further fibrillation. The clearance between the upper and lower grinder was kept negative as the pulp was being passed through them. The samples were collected after fibrillating at different cumulative energies. Three aliquots were taken from each of the samples and dried for 24 hours to obtain the solids content and then averaged to find the mean solids content value.

Chitosan solution 3% (CH) and cationic starch solution were prepared following prior protocols (Tokarz, 2006) (Tyagi et al., 2019). Table 2, below, shows pulp samples, fiber types, biopolymers such as chitosan solution (CH), cationic starch (St) and Glycerol used for making composite films and their processing conditions. Medium molecular weight chitosan and glycerol were purchased from Sigma-Aldrich (St. Louis, Missouri, United States of America). Two different temperature conditions: 80T and room temperature RT; were used.

Table 2: Coating film formulation (Target solids - 2.3%, mixing time - 30 minutes)

All the MFC composite solutions were prepared and used in several trials. The coating films were made by following the solvent cast method. See Figure 12. The methods described below were used to analyze the films and casting solutions. Wet Coating Properties:

Apparent viscosity was measured according to TAPPI T 648 OM-14 using a Brookfield DV-III Ultra viscometer (Broodfield Engineering Laboratories, Inc., Middleboro, Massachusetts, United States of America) with spindle number 5 at a range of speed from 25-250 rpm at 20°C. Morphological and chemical properties:

The surface morphology of the film samples was examined using a FEI Verios 460L field emission scanning electron microscope (SEM) at an accelerating voltage of 2 kv and 13 pA current. Prior to imaging, samples were sputter-coated with a thin layer of gold in a low vacuum of 90 mTorr of Ar gas pressure with an accelerating voltage of 600 V for 3 minutes at a coating rate of 7 nm/min. The chemical characterization of the film surface was carried out using a Bruker-Opus attenuated total reflection-Fourier-transform infrared (ATR-FTIR) instrument (Bruker, Billerica, Massachusetts, United States of America) within the range of 400 to 6000 cm^-1 wavenumber with 4 cm^-1 resolutions for 64 scans. Fiber characterization of each paper type was carried out using the TAPPI T271 method with a HiRes fiber quality analyzer (FQA) from Op Test Equipment (Hawkesbury, Ontario, Canada)

Barrier Properties:

Barrier properties such as water resistance, water vapor transmission rate (WVTR), resistance to air permeance, and oil and grease resistance (OGR) of film were measured. The WVTR was tested using the water cup method in accordance with the ASTM E-96 test method, by using standard cups from Thwing-Albert Instrument Company (West Berlin, New Jersey, United States of America). For resistance to air permeance, the TAPPI ‘Gurley Densometer method’ of air resistance T460 was used. Results are reported as Gurley seconds per 100 ml air displacement (Gs/lOOml). The OGR and OGR crease test were tested by performing a 3M Scotchban test, which has been adopted under TAPPI T559. Results were reported as kit number from 1 through 12. OGR crease test was carried out by using 10 kg roller to crease the film. The hot oil test (65°C for 20 min) with Mazola oil and regular oil test (room temperature overnight) with sunflower oil were carried out as described below to analyze oil absorption of the film. The water resistance test of the sample was also carried out at different time interval.

With more particular regard to the hot oil test, a test procedure based on the standard “Harmonized Hot Oil Test For Printed, Finished Foodservice Products” by FOODSERVICE PACKAGING INSTITUTE® (FPI) (2013 update) was performed with several modifications to provide for testing of films and coated papers. Generally, the test uses dyed oil to determine the grease resistance and soak-through of films or coated papers for packaging and other related products.

The hot oil test was performed using following materials: Mazola com oil or another type of oil; a red dye (e.g., D53004, sold under the tradename CHROMATINT® Red IK Liquid, Chromatech Inc., Canton, Michigan, United States of America), a glass or steel beaker, a hot plate capable of maintaining an oil temperature of 65°C-68°C (150°F-155°F), a laboratory thermometer; a holder to position the specimen to hold ink in contact with the top surface of the specimen during the test with a test area of 16 cm² (as found in the Tappi T530 Size test for paper by ink resistance (Hercules-type method)); and a container for holding used oil, paper towels, and stopwatch. To perform the test, a specimen was prepared by cutting a coated paper or film specimen in a round shape with an approximate area of 45 cm² for proper clamping and to avoid any leakage. The testing steps are described below. See also Figure 18. Testing Procedure:

• Pipette 3.8ml of the red dye into one gallon of corn oil and mix thoroughly for a concentration of 0.1%. A new solution is prepared at least every six months.

• Measure the initial weight of the specimen.

• Place the sample holder on a flat surface.

• Put a paper towel above the base of the sample holder.

• Place the specimen on top of the paper towel and then clamp the flexible ring to fix the position of specimen along with the paper towel.

• Heat dyed corn oil in a 300 ml beaker to 65°C-68°C (150°F-155°F). Temperature maintained by controlling the temperature through a hot plate.

• Take 10 ml of heated oil and pour it into the specimen holder.

• Let specimen stand undisturbed for 20 minutes.

• After 20 minutes, pour out the oil from the specimen holder in a holding container.

• Wipe the remaining oil with a paper towel, and immediately inspect the backside of the specimen for soak-through and mark those areas with a pen or pencil. Examine stains on the back of specimen. Staining on the bottom of the specimen, without penetration, is not a failure. If this occurs, the sample passes.

• Examine the specimen for evidence of soak through on the paper towel. Any oil found on the towel constitutes a failure. If no oil is found on the towel, the specimen passes.

• After wiping out the oil from the specimen, take the final weight of the specimen.

• Repeat the above procedure with the remaining specimens, using the same sequence that was used in filling the specimens, so that each specimen is examined after 20 minutes Calculations:

Weight gain in g = (Final weight of specimen - Initial weight of specimen) g

Hot oil absorption, g/m² = (Final weight of specimen - Initial weight of specimen) g/ area of the flexible ring (0.0016 m²)

The room temperature oil absorption test was performed using the same procedure except that 10 ml of room temperature (22°C-23°C) sunflower seed oil was poured into the specimen holder and the sample left undisturbed overnight.

Mechanical Tests:

Tensile strength of the films was analyzed by following TAPPI T 494 method.

Fourier Transform Infrared Spectroscopy (FTIR): A PerkinElmer spectrometer sold under the tradename SPECTRUM™ (PerkinElmer Corporation, Waltham, Massachusetts, United States of America) was used to record the FTIR spectra of the polymers (Starch & Chitosan), microfibrillated cellulose (MFC), and composites. Each sample was brought into the contact area of a diamond crystal of an attenuated total reflectance (ATR) which has a circle of ~1.5 mm in diameter. All spectra were collected between 4000 and 500 cm^-1 with a 20 scans per sample and a resolution of 4 cm ¹. A baseline correction was performed before analyzing the samples and all the spectrum was collected at the same baseline.

Discussion: All the different films were developed in four different trials and their properties were analyzed. Table 3, below provides a summary of basis weight, bulk, strength properties and barrier properties of the films. Tables 4 and 5, below, provide data from the hot oil absorption and room temperature oil absorption tests, respectively.

Table 3. Summary of Properties of MFC films

15

Figures 13A-13E show the viscosity as function of rpm. Both in the ease of modified and unmodified MFC, the composite solutions with chitosan and glycerol at room temperature showed the highest viscosity. A similar trend was observed in the case of CPH-based film solutions. From the trend, it can be assumed that bond formation or network formation between anionic carboxyl groups and cationic amine groups from chitosan has taken place (Heggset et al., 2017). However, the effect of temperature is not completely understood due to effect of moisture since the heating treatment caused change of moisture content. For all these coating solutions, the viscosity decreased with increasing rpm or shear rate upon shearing, thus displaying the shear-thinning behavior of coating solutions, which is desirable during coating applications (Tyagi et al., 2018). Bulk:

Bulk is an important property for packaging products. It can affect the porosity, pore-volume, thickness, liquid absorption, and air/gas permeability (Kartovaara et al., 1985). CPH films made from either direct pulp or MFC have significantly high bulk. See Figures 14A-14D. Without being bound to any one theory, this is believed to be related to the nature of the fiber and the composition of cocoa pod husk, which has high pectin content compared to other pulp (Daud et al., 2013). Film Morphology:

Figures 15A-15C show SEM images of MFC films at different conditions. It can be inferred from the images that most of the MFC films showed good uniformity, which helps to develop good barrier property. Particularly in case of films prepared under higher temperature conditions, the films showed good uniformity. Compare for example, the images of the carboxymethylated composite film with chitosan and glycerol prepared at room temperature and at 80°C. See Figures 15B and 15C. At lOOOx magnification, the film prepared high temperature appears more uniform than the one prepared at room temperature. Without being bound to any one reason, this is believed to be attributable to higher temperatures causing better interaction between MFC, chitosan and glycerol. FTIR spectroscopy:

Figures 16A-16D show the FTIR spectra of various polymers, MFC, and composites. The appearance of a peak in the region of 1030-1170 cm'¹ is attributed to the stretching vibrations of the C-O-C of primary and secondary hydroxide groups of the carbohydrates. This kind of stretching vibrations is absent in the starch and chitosan polymers. The peaks at 1281, 1370 and 1427 cm ¹ represent aromatic esters, ether, and phenol compounds respectively which are absent in starch and chitosan spectra (Tanpichai et al., 2019).

The peak at 1648-1678 cm'¹ in the CM, PI, and CMPI modified cellulose, unmodified cellulose and their composites is related to the presence of the C=O stretching of carboxyl and ketone groups from modified MFC or polymers (Pelissari et al., 2014). Moreover, the peak corresponding to 2900 cm'¹ due to the symmetric and asymmetric C- H stretching and peak at 3400 cm'¹ are characteristics for OH stretching of cellulose (Cui et al., 2016). The stretching vibrations of C=O in the composites are shifted slightly to the right due to the presence of glycerol in the composites. Lack of any distinctive peak in chitosan-based composites leads to the assumption that the crosslinking between MFC and chitosan is based on a physical interaction between the reducing ends of cellulose and the primary amines of chitosan, promoting the dehydration of chitosan (Stefanescu et al., 2012) (Benghanem et al., 2017). See Figure 17. A similar explanation can be given for the starch-based composites.

Oil Absorption:

Oil resistivity can be a consideration for films and coated papers used to be packaging applications. The barrier properties of the presently disclosed films have been tested against hot and room temperature oil for 20 minutes and 15 hours respectively. See Figures 18 and 19A-19D. See also Tables 4 and 5, above. The presently disclosed fdms showed good results in terms of oil resistivity to both hot oil and room temperature oil. All the films tested passed the hot oil test (see Figure 18) with no stain on the tissue paper. Figures 19A and 19B show weight gain of films prepared from different modified and unmodified MFC composites of the presently disclosed subject matter in the hot oil test. The highest weight gain for the films tested was 1.98% (1.19 gsm), which is far below the accepted value of 5% weight gain (Food service packaging institute, FPI). Overall, a relatively higher percent of weight gain was observed for unmodified hemp MFC composites, while modified hemp MFC composites showed less weight gain, especially the one with cationic starch. See Figure 19A, e.g., circled bars. It was also observed that films prepared from formulations developed at 80°C gained less weight than the films prepared from formulations developed at room temperature. Without being bound to any one theory, this is believed to be related to improved mixing at higher temperatures and enhanced interactions among the functional groups of the MFC and the other polymers in the composites.

Weight gain of the films in the oil absorption tests also depended on the basis weight of the films. Higher basis weight films gained less weight, while films with lower basis weight (e.g., basis weight less than 10 gsm) gained more weight. A similar trend of weight gains also has been observed when performing the regular temperature oil test for a longer time. See Figures 19C and 19D.

The WVTR rates of the hemp-based MFC films were measured. See Figures 20A- 20D. Films comprising carboxymethylated and unmodified hemp hurds showed consistency in terms of WVTR value (10-20 g/m².mm/day). However, cocoa pod husk (CPH) pulp-based films showed high WVTR value compared to CPH MFC based films. See Figure 20A. This could be because of the morphology and distribution of fiber and the composition since CPH has high pectin content and shorter fiber has better orientation than longer fiber (Daud et al., 2013). The hemp mix-based MFC composite films have also showed comparatively high WVTR value compared to hemp hurds-based MFC films. See Figure 20B. The hemp mix-based MFC composite films in general also had lower density than the hemp hurds-based MFC composite films. See Figure 20E. The WVTR data was compared to film densities. See Figure 20F. Films with higher density generally had lower WVTR.

Oil and Grease Resistance:

For oil and grease resistance, 12 kit solutions have been used which are made of hexane, toluene, and castor oil at different ratios. As kit number increases, the amount of hexane and toluene solvents increase and the amount of castor oil decreases in the kit solution. Thus, at a higher kit number, penetration of the kit solution through the paper is becomes more favorable due to the lower viscosity of the kit solution and due to the comparatively more non-polar nature of the kit solution. All of the films tested passed kit number 12 except the cocoa pod husk films. See Figures 21 A and 2 IB for exemplary images of films passing or failing kit testing. The 100% CPH film failed at kit number 3, Attorney Dock a CPH film with 20% chitosan prepared at 80°C failed at kit number 7, a CPH film with 80% chitosan and 2% glycerol prepared at 80°C failed at kit number 5. Without being bound to any one theory, it is believed that these results are based on the CPH films being made from a pulp that is more porous than the corresponding MFC films, and becasue the fiber bonding is higher in a MFC-based film than in a normal film due to effect of fines (Kullander et al., 2012).

Samples that passed kit umber 12 were creased with a 10 kg roller and then the kit solutions were used. See Figure 22. Both creased and uncreased samples passed kit number 12.

Water Resistance:

To measure water resistance, a sample was taken from a film and the weight of the sample was measured. Then, the sample was placed in water and the weight of the sample was remeasured at different time intervals. While unmodified 100% CPH MFC film started dispersing after two hours, almost all other films tested remain intact, even after 32 days. See Figures 23A-23C.

Gas Barrier:

Air resistance was measured for different film samples. All the films tested showed above 3000 Gurley seconds (higher Gurley seconds or units correspond to lower permeance), except for CPH films that were made from direct pulp. Without being bound to any one theory, this result is believed to be related to the high percentage of fines and high fiber-fiber bonding in the MFC samples. Samples with chitosan and glycerol prepared at room temperature showed the highest air resistance (see Figure 24), which is indicative of proper entanglement among the biopolymers and pulp at room temperature. Tensile properties:

The tensile index of the films was measured to assess their strength properties, as strength can be a property of interest for packaging products. Multiple trials were carried out to analyze the data. See Figures 25A-25D. As shown in Figures 25A, 25C, and 25D, in three different trials, films prepared from carboxymethylated hemp hurds MFC-based composites showed comparatively better strength than films comprising unmodified hemp hurds MFC. The reason could be better physical network/cross linking among the biopolymers in the case of the modified MFC. This was also observed in the SEM images. Attorney Dock

See Figures 15A-15C. Without being bound to any one theory, the higher crosslinking is believed to be related to the higher numbers of carboxyl groups on the carboxymcthylatcd MFC (see Figure 9), which can help to form a better network. Also, during MFC preparation, it was observed that modified MFC has a higher fine content than the unmodified MFC (see Figure 6), which can contribute to better strength. However, a different trend was observed in case of hemp mix-based MFC composites. See Figure 25B. Without being bound to any one theory, this result is believed to be due to the nature of the fiber itself, since hemp mix is a combination of long fibers and a small amount of short fibers. It was also observed that for films produced from formulations mixed at higher temperature, the tensile index was often relatively high, especially in the case of composites also comprising starch, presumably due to better cross-linking between the biopolymers. In case of mixtures of modified MFC, particularly for PI-MFC (see Figure 25D), the film formulations were prepared at room temperature because, at high temperature, PI-MFC tended to form brittle films. However, these films still showed good strength. Even though the values varied from trial to trial, the lowest value was observed for a film comprising CM-PI-MFC prepared at high temperature with chitosan. It is assumed that this is the result of the agglomeration of fiber. Similar trends were observed for when stretch values were measured. See Figures 26A-26D.

In summary, agricultural residue- and by-product-based MFC were evaluated for film/coating development for flexible packaging development. MFC was prepared from both high kappa kraft and autohydrolysis (nearly chemical-free) pulped hemp hurds, high kappa kraft conventionally bleached and unbleached cocoa pod husk, and high kappa kraft enzyme treated conventionally bleached hemp mix. Different types of chemical modification were carried out on the pulps to make modified MFCs. The different types of MFC were used with biopolymers, such as chitosan, glycerol, AKD, and cationic starch, at different ratios and at two different temperatures to make composite films. All the films are flexible and showed high barrier properties. For example, the films showed high oil, grease, water and air resistance. The modified MFC-based films had good strength properties, as well. In repeated trials, the data showed consistency and the barrier properties were measured for low basis weight films. Based on the data, the presently disclosed film composites showed good qualities for coating purposes. Attorney Dock

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Claims

CLAIMS What is claimed is:

1. A packaging material comprising a film or a coating layer comprising agrobased microfibrillated cellulose (A-MFC), wherein said A-MFC comprises a microfibrillated cellulose (MFC) prepared from a pulp from a non-wood lignocellulosic feedstock, wherein the film or coating layer has a weight gain of less than about 5 percent (%) and/or less than about 2.5 grams per square meter (g/m²), when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees Celsius (°C).

2. The packaging material of claim 1, wherein the non-wood lignocellulosic feedstock comprises one or more agricultural residue and/or industrial by-product.

3. The packaging material of claim 2, wherein the non-wood lignocellulosic feedstock is selected from the group consisting of hemp hurds, a mixture of hemp hurds and hemp bast, bagasse, cocoa pod husks, and combinations thereof.

4. The packaging material of any one of claims 1-3, wherein the A-MFC comprises modified A-MFC, wherein the modified A-MFC comprises MFC derived from a chemically modified pulp.

5. The packaging material of claim 4, wherein the modified A-MFC comprises carboxymethylated A-MFC; oxidized A-MFC; carboxymethylated and oxidized MFC; or a combination thereof.

6. The packaging material of claim 5, wherein the oxidized A-MFC comprises dialdehyde cellulose.

7. The packaging material of claim of any one of claims 1-6, wherein the film or coating layer comprises about 5 weight percent (wt%) to about 90 wt% A-MFC, optionally wherein the film or coating layer comprises about 40 wt% A-MFC to about 80 wt% A-MFC.

8. The packaging material of any one of claims 1-7, wherein the film or coating layer further comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a polyhydroxyalkanoate (PHA), and alkyl ketene dimer (AKD).

9. The packaging material of any one of claims 1-8, wherein the A-MFC has a total fines level of about 50% to about 95%.

10. The packaging material of any one of claims 1-9, wherein the A-MFC has an average fiber length of about 0.1 mm to about 0.45 mm.

11. The packaging material of any one or claims 1-10, wherein the film or coating layer has a thickness of about 1 micrometer to about 200 micrometers, optionally wherein the film or coating layer is a coating layer with a thickness of about 1 micrometer to about 30 micrometers or a film with a thickness of about 10 micrometers to about 200 micrometers, further optionally wherein the film has a thickness of about 20 micrometers to about 140 micrometers.

12. The packaging material of any one of claims 1-11, wherein the film or coating layer has a bulk of about 0.5 cubic centimeters per gram (cm³/g) to about 2.0 cm³/g.

13. The packaging material of any one of claims 1-12, wherein the film or coating layer has a weight gain of less than about 2% and/or less than about 1.19 g/m², when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees °C.

14. The packaging material of any one of claims 1-13, wherein the film or coating layer has a weight gain of less than about 3% and/or less than about 1.8 g/m² when contacted with room temperature oil for 15 hours.

15. The packaging material of any one of claims 1-14, wherein the film or coating layer has a water vapor transmission rate (WVTR) of less than 50 grams per square meter millimeter per day (g/m².mm/day), optionally less than 15 g/m².mm/day.

16. The packaging material of any one of claims 1-15, wherein the film or coating layer has a density of about 0.3 grams per cubic centimeter (g/cm³) to about 2.1 g/cm³.

17. The packaging material of any one of claims 1-16, wherein the film or coating layer has a tensile index of about 30 Newton meter per gram (Nm/g) or more.

18. The packaging material of any one of claims 1-17, wherein the film or coating layer has a stretch of about 1.5% or higher.

19. The packaging material of any one of claims 1-18, wherein the packaging material is a food or beverage packaging material.

20. The packaging material of any one or claims 1-19, wherein the packaging material further comprises a substrate, wherein said substrate is coated on at least one surface by the film or coating layer comprising A-MFC, optionally wherein the substrate is a flexible substrate.

21. The packaging material of claim 20, wherein the substrate comprises paper or another biodegradable and/or sustainable material, optionally wherein the paper comprises or consists of papermaking fibers derived from a waste biomass.

22. A method for preparing a film that has a weight gain of less than about 5 percent (%) and/or less than about 2.5 grams per square meter (g/m²), when contacted with hot oil for 20 minutes, wherein said hot oil has a temperature of about 65 degrees Celsius (°C), the method comprising:

(a) preparing a suspension comprising agro-based microfibrillated cellulose (A-MFC), wherein said A-MFC is microfibrillated cellulose (MFC) prepared from a pulp from a non- wood lignocellulosic feedstock;

(b) forming a web using from the suspension; and

(c) drying the web, thereby providing the film.

23. The method of claim 22, wherein the non-wood lignocellulosic feedstock comprises one or more agricultural residue and/or industrial by-product, optionally wherein the non-wood lignocellulosic feedstock comprises hemp hurds, a mixture of hemp hurds and hemp bast, cocoa pod husks, or a combination thereof.

24. The method of claim 22 or claim 23, wherein preparing the suspension comprising A-MFC comprises fibrillating a suspension of pulp from a non-wood lignocellulosic feedstock, wherein said pulp has a primary fines level of more than 10%, optionally wherein the pulp has a primary fines level of about 15 % to about 50%.

25. The method of claim 24, wherein the pulp is a kraft pulped pulp, an autohydrolyzed pulp, an unbleached pulp, higher yield pulp, or higher lignin containing pulp.

26. The method of claim 24 or claim 25, comprising chemically modifying the pulp in an aqueous medium prior to fibrillation.

27. The method of claim 26, wherein chemically modifying the pulp comprises carboxymethylating the pulp, oxidizing the pulp, or carboxymethylating and oxidizing the pulp.

28. The method of claim 24 or claim 25, comprising carboxymethylating the pulp prior to or after fibrillation.

29. The method of any one of claims 22-28, wherein preparing the suspension comprising A-MFC comprises contacting the A-MFC with a liquid, optionally water, to provide a suspension comprising a total solids content comprising at least about 50 weight percent (wt%) of the A-MFC, optionally to provide a suspension comprising a total solids content comprising about 50 wt% to about 80 wt% A-MFC.

30. The method of any one of claims 22-29, wherein the suspension has a solids content of about 2.0% or higher and/or about 5% or lower.

31. The method of any one of claims 22-30, wherein the suspension comprising A-MFC further comprises one or more of chitosan, cationic starch, glycerol, triethyl citrate, a polyhydroxyalkanoate (PHA), and alkyl ketene dimer (AKD).

32. The method of any one of claims 22-31, wherein preparing the suspension comprises mixing the suspension at a temperature between about room temperature and about 80 degrees Celsius (°C) for a period of time, optionally for about 30 minutes.

33. The method of any one of claims 22-32, wherein step (b) comprises casting a web from the suspension.

34. The method of any one of claims 22-33 , wherein the method further comprises applying the film to a surface of a substrate, optionally a paper substrate, to provide a film coated substrate.

35. The method of any one of claims 22-34, wherein the method further comprises forming a packaging material from the film or from a film coated substrate.