WO2016075370A1

WO2016075370A1 - Cationic parenchymal cellulose

Info

Publication number: WO2016075370A1
Application number: PCT/FI2015/050785
Authority: WO
Inventors: Antti Laukkanen; Jason Mckee; Tapio Saarinen; Henrikki Mertaniemi
Original assignee: Betulium Oy
Priority date: 2014-11-11
Filing date: 2015-11-11
Publication date: 2016-05-19
Also published as: EP3218415A1

Abstract

The present description is related to the field of derivatised parenchymal cellulose obtained by derivatizing parenchymal cellulose to comprise cationic substituents wherein the parenchymal cellulose derivative is capable of forming a continuous gel from an aqueous dispersion at least one point in a concentration range of from about 0.05 wt.% to about 99 wt.% based on total weight of the gel.

Description

CATIONIC PARENCHYMAL CELLULOSE

FIELD OF THE INVENTION

The present description is related to the field of parenchymal cellulose based materials. More particularly, it provides novel cationic cellulose from a non-wood source, such as vegetable waste products or food chain waste streams.

BACKGROUND

Cellulose is a substance of great industrial importance and having numerous applications. Primary source of cellulose in industrial applications is wood-based cellulose or cellulose derivatives. However, in using wood-based raw-material there are several problems such as environmental issues relating to unsustainable use of land and soil and heavy energy consumption required to grow, harvest and process wood-based material. These issues have created a need to find, on one hand, alternative sources of cellulose for producing new cellulosic materials. Further, the industry is constantly searching for more economical methods and raw materials to produce high quality cellulosic products.

Spent sugar beet pulp is a by-product of the sugar beet processing industry. It comprises predominantly pectin, arabinogalactan and cellulose. Other naturally occurring biological constituents of sugar beets, such as fats, proteins, soluble oligosaccharides, and other low molecular weight components, are largely extracted from sugar beets during the removal of sucrose therefrom. The remaining polysaccharides in sugar beet pulp comprise generally conjugated, particulate cell residuals having morphologies generally characteristic of parenchymal cells found in certain higher plants.

Few economical uses have been found for spent parenchymal sugar beet pulp. For example, sugar beet pulp is a material which spoils rapidly and consequently constitutes a local environmental problem. In contrast to the solid residue obtained from the processing of sugar cane, sugar beet pulp has a negative fuel value and it takes more energy to dehydrate sugar beet pulp to a combustible state than can be recovered from its burning. Thus, alternative uses for parenchymal pulp are needed.

EP0102829 discloses a process for isolating the cellulosic and hemicellulosic constituents of sugar beet pulp. However, the process requires mechanical classification and a multi-step water removal, and storage and transport of the resulting suspension is difficult because it can only be stored at low cellulose content and is not easily rehydrated once dried.

l US5964983 discloses a process for producing parenchymal cellulose from sugar beet involving alkali and/or acid extraction and subjecting the material to a complicated multi-step treatment comprising mechanical grinding, a pressure drop of at least 20MPa, high velocity shearing action followed by high velocity decelerating impact. Previously, cationic nanocellulose has been produced from wood-based cellulose. This process, however, requires high-shear fluidisation to form viscoelastic networks. A problem of the wood-based cellulose is that the fibrillated gel cannot easily be concentrated for large- scale transportation. Hence, a method is needed that allows providing cellulosic materials having viscoelastic networks with the ability to be concentrated using e.g. filtration techniques.

Until now, all known parenchymal celluloses have had disadvantages either in their properties or in the processes for their production.

SUMMARY OF THE INVENTION

It is an aim of the present invention to solve or alleviate at least some of the problems related to prior cellulosic materials and their production methods, as discussed above. In particular, an aim of the present invention is to provide from novel raw material sources cellulosic materials that have a homogeneous distribution and good rheological properties in aqueous dispersions and/or good mechanical properties in a dry state.

Accordingly, as a first aspect there is provided a parenchymal cellulose derivative obtained by derivatizing parenchymal cellulose to comprise cationic substituents wherein the parenchymal cellulose derivative is capable of forming a continuous gel from an aqueous dispersion at at least one point in the concentration range of from about 0.05 wt.% to about 99 wt.% based on total weight of the gel.

The present parenchymal cellulose derivative has several advantageous properties compared to wood-based cellulose and wood-based derivative materials. Firstly, the present invention is able to utilize non-wood raw material from agricultural waste streams to produce cellulosic materials having improved rheological properties, thereby solving problems related to use of wood-based raw materials.

Further, the present invention is particularly advantageous as it provides a cationic cellulose derivative which has excellent gel and film forming properties that have many advantages when used in industrial applications. Wood-based pulp forms a suspension, which settles out of the continuous phase without mechanical agitation. Typically, wood-based cellulose pulp requires high-shear fibrillation to form gels. This is a problem as the resulting systems cannot easily be concentrated, once fibrillated. Parenchymal-based chemically modified systems readily form gels even without high-shear fibrillation. The chemically modified gels can be concentrated using conventional filtration techniques, allowing for more efficient transportation, due to higher solids contents.

As the parenchymal cellulose derivative forms a continuous gel, large-scale fibrillation becomes feasible as the master batch forms a stable homogeneous gel. Hence, there will be no concentration gradients after the fibrillation process. In contrast, wood-based cellulose pulp settles out of the continuous phase, which can lead to concentration gradients in large- scale homogenization processes.

The present parenchymal cellulose derivative has cationic charge and, accordingly, it is also advantageous in being able to bind and remove substances having an anionic charge from the water. Thus, the present materials are useful as flocculants and binders in paper and board industry or in water treatment and purification applications, respectively. Moreover, the cationic charge gives a strong internal electrostatic repulsion for the nanofibrils located in the non-fibrillated derivatized parenchymal cellulose, which enables easy fibrillation process for fibrillated parenchymal cellulose.

The parenchymal cellulose derivative of the present invention or the composition comprising it may include a solvent in which the derivatized parenchymal cellulose is substantially insoluble at a high substitution degree or without cationic substitution. Suitable solvents include water, alcohol, and oil, with water being preferred. Thus, by selecting a suitable substitution degree, water-solubility of the derivatized material can be modified.

According to a second aspect there is provided a composition comprising nanofibrillar parenchymal cellulose derivative obtained by fibrillating the parenchymal cellulose derivative of the first aspect.

According to a third aspect there is provided a composition comprising the parenchymal cellulose derivative of the first aspect.

According to a fourth aspect there is provided a method of modifying rheological properties of a composition of matter, said method comprising the step of incorporating into said composition of matter the parenchymal cellulose derivative of the first aspect, the fibrillated parenchymal cellulose derivative of the first aspect, or the composition according to the second or the third aspect. The present parenchymal cellulose derivative, as well as the compositions comprising it, are able to modify rheological properties of a composition of matter when incorporated or mixed into it. Accordingly, the present parenchymal cellulose derivative may be used to modify and improve one or more of the properties selected from viscosity, suspension stability, gel insensitivity to temperature, shear reversible gelation, yield stress, and liquid retention of the composition of matter. Compositions of matter whose rheological properties may be modified in this manner include foods, pharmaceuticals, nutraceuticals, personal care products, fibres, papers, paints, coatings, and construction compositions. More specifically, suitable compositions of matter include oral care products; creams or lotions for epidermal application, including moisturizing, night, anti-age, or sunscreen creams or lotions; food spreads, including reduced fat, low fat, or fat free food spreads (for example, mayonnaise); and drilling fluids. The modification of rheological properties can be further improved by using the fibrillated parenchymal cellulose derivative or compositions comprising it.

According to a fifth aspect there is provided a method of improving at least one of sizing, strength, scale control, drainage, dewatering, retention, clarification, formation, adsorbency, film formation, membrane formation, and polyelectrolyte complexation during paper or board manufacture, said method comprising the step of using the parenchymal cellulose derivative of the first aspect or the composition of the second or the third aspect. The use may include incorporation of the present parenchymal cellulose derivative or the present compositions into the paper or board. The rheological properties can be further improved by using the fibrillated parenchymal cellulose derivative or compositions comprising it.

According to a sixth aspect there is provided a method for improving the stability of an emulsion, dispersion, or foam system, said method comprising the step of including in the system the parenchymal cellulose of the first aspect or the composition of the second or the third aspect. The stability can be further improved by using the fibrillated parenchymal cellulose derivative or compositions comprising it.

According to a seventh aspect there is provided a process for producing of cationic parenchymal cellulose gel, the process comprising: a. providing parenchymal cellulose and optionally hydrolyzing it with an acid and/or an alkali; b. recovering the cellulosic residue; c. cationizing the cellulosic residue; d. harvesting the cationic cellulose as a hydrogel; and, optionally e. fibrillating the hydrogel from step (d) wherein the fibrillation is carried out to provide increased storage modulus compared to the non-fibrillated suspension.

An advantage of the present method is that it can easily be implemented at the site where suitable raw material comprising parenchymal cellulose is produced. Also, the non-fibrillated chemically modified parenchymal can be concentrated by filtration techniques.

The process is preferably carried out in the sequence a., b., c, d. and optionally e.

In the process the cationic parenchymal cellulose gel comprises preferably parenchymal cellulose derivative according to the first aspect after step e.

According to an eighth aspect there is provided a cationic parenchymal cellulose gel obtained by the above process.

According to an ninth aspect there is provided a hair product comprising the parenchymal cellulose derivative of the first aspect or the composition of the second or the third aspect.

According to another aspect there is provided a hair conditioning composition comprising the parenchymal cellulose derivative of the first aspect or the composition of the second or the third aspect.

According to a tenth aspect there is provided a method for improving condition of hair, the method comprising a step of depositing the parenchymal cellulose derivative according to the first aspect, or the composition of the second or the third aspect, on the hair surface.

The present parenchymal cellulose derivative may have several advantageous properties in hair products and in hair conditioning, such as improved combability, flyway, body and curl retention.

Different embodiments of the present invention will be illustrated or have been illustrated only in connection with some aspects of the invention. A skilled person appreciates that any embodiment of an aspect of the invention may apply to the same aspect of the invention or to other aspects of the invention.

BRIEF DESCRIPTION OF THE FIGURES

Figs. 1A, 1 B, 1 C and 1 D disclose rheological properties of a non-fibrillated and fibrillated derivatized parenchymal cellulose made from sugar beet pulp by cationization according to example 6 to high degree of substitution. The aqueous dispersions are evaluated at 0.5 wt% concentration. Non-fibrillated sample (hollow symbols) and fibrillated sample (solid symbols).

Fig 2A, 2B, 2C and 2D disclose rheological properties of a non-fibrillated and fibrillated derivatized parenchymal cellulose made from potato pulp by cationization according to example 5 to high degree of substitution. The aqueous dispersions are evaluated at 0.5 wt% concentration. Non-fibrillated sample (hollow symbols) and fibrillated sample (solid symbols).

Fig 3A, 3B, 3C and 3D disclose rheological properties of a fibrillated derivatized parenchymal cellulose made from sugar beet pulp by cationization according to example 7 to low degree of substitution. The aqueous dispersions are evaluated at 0.5 wt% concentration.

Fig 4 discloses results of the tensile test results of solvent-cast films.

Figure 5. SEM images of a human hair coated with cationic nanofibrillar cellulose. Left: scale bar 10 micrometers, Right: image is taken from an area of the left-hand side image marked with square. Scale bar 200 nm

DETAILED DESCRIPTION

The raw material which is used to produce the parenchymal cellulose derivative according to the present invention may be obtained from any suitable plant source, including plant species that predominantly contain parenchymal cell types wherein the majority of the cellulose is located in primary cell walls. Suitable raw materials include soybean hulls, pea hulls, corn hulls, bagasse, corn, vegetables, rice, and fruits. Especially well suitable raw materials are sugar beet, bagasse, cassava and/or potato pulp.

In an embodiment the parenchymal cellulose raw material which is used to produce the parenchymal cellulose derivative according to the present invention is fresh, never dried, or dried.

The present parenchymal cellulose derivative is capable of forming a continuous gel in water throughout the concentration range of between about 0.05 % and about 99%, such as throughout the concentration range of between about 0.5 % and about 50 %, or at 0.1 %, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1 %, 1 .5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 46%, 47%, 48%, 49%, 50%, 51 %, 52%, 53%, 54%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% in water.

In an embodiment the parenchymal cellulose derivative is capable of forming a continuous gel from an aqueous dispersion at at least one point in a concentration range of from about 0.1 wt.% to about 2 wt.% based on total weight of the gel. This concentration range is particularly useful for storing and transporting. In general, native cellulose is always in a microfibrillate form, these microfibrils being associated to a greater or lesser degree to form fibers, walls and membranes. Each cellulosic microfibril is constituted by a rigorous assembly of parallel cellulose chains resulting from the method by which the cellulose is biosynthesized. Cellulose microfibrils are generally considered to contain only few faults along their axis. Their mechanical properties are close to the theoretical mechanical properties of cellulose: a tenacity in the order of 130 GPa and a fracture toughness in the order of 13 GPa. Cellulosic microfibrils are thus of interest if they can be dissociated and reformed.

Cellulose microfibrils are usually associated to a high degree in walls or fibers. The microfibrils in secondary walls are organized into highly oriented layers which form a fiber which cannot be dissociated; the microfibrils in primary walls are deposited in a disorganized fashion. The parenchyma is a typical example of primary wall tissue. While it is difficult, if not impossible, to separate secondary wall cellulose microfibrils without damaging them, it is easy to dissociate primary wall microfibrils, not only because of their looser organization but also because interstitial polysaccharides, which are usually anionically charged, constitute a large percentage of these walls.

Preferably the parenchymal cellulose is obtained from purified, optionally bleached parenchymal cellulose. Even more preferably the cellulose is substantially free from wood- based cellulose structures present in secondary cell walls. The substituent which provides cationic charge to the derivatized parenchymal cellulose may be, or include, an amine. A quaternary amine is preferred. Cationic derivative can be selected from the group consisting of alkyl substituted nitrogen compounds, aryl substituted nitrogen compounds, alkyl-aryl substituted nitrogen compounds, or alkyl substituted nitrogen halides. The substituent providing the cationic charge may be directly attached to the cellulose by a chemical bond. In another embodiment the substituent providing the cationic charge is attached to the cellulose through a linker substituent. In an embodiment the substituent is selected from the group consisting of epoxide groups, amines, or other cationic functionality, such as glycidyltrimethylammonium chloride.

The derivatized parenchymal cellulose has preferably a degree of substitution which makes it highly dispersible in an aqueous medium. In an example embodiment the degree of substitution is at least 0.05, preferably at least 0.1. In an embodiment the degree of substitution is between about 0.05 and about 0.5, and more preferably between about 0.05 and about 0.3. Suitable degrees of substitution include 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 , 0.1 1 , 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0,21 , 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31 , 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41 , 0,42, 0.43, 0.44, 0.45, 0.46. 0.47, 0.48, 0.49, and 0.5.

The derivatized parenchymal cellulose forms a continuous gel when dispersed in water, even at low concentration. A continuous gel in this context means a mixture of derivatized parenchymal cellulose and water, where the derivatized parenchymal cellulose component does not settle out of the continuous phase at rest and where G'>G", where G' is the dynamic storage modulus and G" is the dynamic loss modulus.

The tangent of the phase angle, i.e. the ratio of loss modulus (G") to storage modulus (G') is a useful quantifier of the presence and extent of elasticity in a fluid. Tan(8) values of less than unity indicate elastic-dominant (i.e. solid-like) behaviour and values greater than unity indicate viscous-dominant (i.e. liquid-like) behavior.

In an example embodiment the parenchymal cellulose derivative has the property of forming from an aqueous dispersion a film having a tensile strength higher than 40MPa.

In an example embodiment the parenchymal cellulose derivative is fibrillated to comprise nanofibrillar cellulose. Nanofibrillar cellulose in this context means cellulose microfibrils or a cellulose microfibril bundle isolated from the above-mentioned raw materials. The aspect ratio of microfibrils is typically very high; the length of microfibrils may be more than one micrometer and the number-average diameter is typically less than 200 nm, such as between 2 and 100 nm. The diameter of microfibril bundles may be greater but is usually less than 1 pm. The smallest nanofibrils are similar to the so-called elemental fibrils, the diameter of which is typically 2 to 12 nm. The dimensions and fiber structures of nanofibrils or microfibril bundles depend on the raw material and the fragmentation method. Nanofibrillar cellulose may also contain other polysaccharides, such as pectin, the amount of which depends on the raw material used. Nanofibrillar cellulose can be isolated from the above-described ceiiulose- containing raw material with an apparatus suitable for the purpose, e.g. a grinder, comminutor, homogenizer, fluidizer, micro- or macrofluidizer and/or ultrasonic disintegrator.

In an embodiment the parenchymal cellulose derivative is fibrillated to comprise nanofibrillar cellulose preferably having a number average diameter of 2-100nm, more preferably of 2- 10nm. There are several widely used synonyms for nanofibrillar cellulose. For example: nanoceilulose, microfibrillar cellulose, nanofibriliated cellulose, cellulose nanofiber, nano- scale fibrillated cellulose, microfibriliated cellulose (MFC), or cellulose microfibrils. After fibrillation the parenchymal cellulose derivative of the present invention has improved rheological properties and the resulting gel comprising the fibrillated cellulose in an aqueous medium has improved storage modulus and yield stress. Also, the properties of a film produced from the resulting gel or dispersion by removing water are improved compared to a film from non-fibrillated material. In particular, such a film has improved tensile strength and optical properties compared to a film produced accordingly from non-fibrillated cellulose.

The derivatized, optionally fibrillated, parenchymal cellulose may be used to modify one or more of the viscosity, suspension stability, gel insensitivity to temperature, shear reversible gelation, yield stress, and liquid retention of the composition of matter. Compositions whose rheological properties may be modified in this manner include foods, pharmaceuticals, nutraceuticals, personal care products, fibres, papers, paints, coatings, and construction compositions. More specifically, possible compositions include oral care products; creams or lotions for epidermal application, including moisturizing, night, anti-age, or sunscreen creams or lotions; food spreads, including reduced fat, low fat, or fat free food spreads (for example, mayonnaise); and drilling fluids.

Alternatively, the derivatized parenchymal cellulose may be incorporated into a coating composition in order to improve its physical and/or mechanical properties. Those properties may include one or more of film forming, levelling, sag resistance, strength, stiffness, durability, dispersion, flooding, floating, and spatter. The present cellulose derivative may be added as a gel, film, or powder.

The present cationic cellulose may further be used in the manufacture of paper and paper products in order to improve at least one of sizing, strength, scale control, drainage, dewatering, retention, clarification, formation, absorbency, film formation, membrane formation, and polyelectrolyte as well as electrolyte complexation during manufacture. Fibrillated present cationic cellulose is particularly preferred for use in this method.

In one embodiment, the present cationic cellulose may be used to increase the rate of drainage and/or dewatering during paper manufacture. In another embodiment, the present cationic cellulose may be used for retention of organic and/or inorganic dispersed particles in a sheet of paper during its manufacture. Representative dispersed particles which may be retained in this manner include pulp fines, fillers, sizing agents, pigments, clays, detrimental organic particulate materials, detrimental inorganic particulate materials, and combinations thereof. In a yet further embodiment, the fibrillated quaternary amine functionalized cellulose may be used in a papermaking machine to improve the uniformity of formation of a sheet of paper during its manufacture. Additionally, the present cationic cellulose may be used in a papermaking machine to improve the strength of a sheet of paper produced on a paper machine. Fibrillated cationic parenchymal cellulose according to the invention is particularly preferred for use in this method.

In each of the present embodiments the cationic cellulose may be used in the presence of one or more of the following: colloidal silica; colloidal aluminium modified silica; colloidal clay, derivatives of starch containing carboxylic acid functionality, hydroxyl groups, amines and other polar and nonpolar functional groups; derivatives of guar gum containing carboxylic acid functionality, hydroxyl groups, amines and other polar and nonpolar functional groups; natural gums or derivatized natural gums containing carboxylic acid functionality, hydroxyl groups, amines and other polar and nonpolar functional groups; polyacrylamides, polyacrylates, poly methacrylates and polystyrenics containing carboxylic acid functionality, hydroxyl groups, amines and other polar and nonpolar functional groups; and combinations thereof. Fibrillated cationic cellulose according to the invention is particularly preferred for use in this method. The present derivatized cellulose may further be used in a method for improving the stability of an emulsion, dispersion, or foam system, by including the derivatized cellulose in the system. Where the system being treated is an emulsion, the emulsion may be produced by processing of an emulsion formulation, in which case the derivatized cellulose may be added to the emulsion formulation prior to completion of processing of the emulsion formulation. Fibrillated cationic cellulose according to the invention is particularly preferred for use in this method.

In an example embodiment the parenchymal cellulose derivative has a yield stress of 0.1 to 100 Pa at 0.5% aqueous dispersion.

In an example embodiment the fibrillated parenchymal cellulose derivative has a property of being capable of forming a film which has a tensile strength higher than before fibrillation. The film may be formed from an aqueous suspension or dispersion by removing water.

In an example embodiment the fibrillated parenchymal cellulose derivative has a property of being capable of forming a gel having an elastic modulus higher than before fibrillation. The gel may be formed by dispersing the present parenchymal cellulose derivative with water. In an example embodiment in the process for producing the present cationic parenchymal cellulose gel the alkali treatment is carried out at 20-90 degrees with an alkali selected from KOH and NaOH. In an example embodiment in the process for preparing of a cationic parenchymal cellulose the parenchymal cellulose is at least one selected from a group comprising any of: sugar beet, bagasse, cassava, and potato, the process further comprising bleaching the cellulosic material either before a. or after step b., d., or e. The bleaching may be carried out with a bleaching agent. Suitable bleaching agents include NaCIC>2, H2O2 and ozone. In another embodiment a method described in WO 2013150184 A1 can be used.

In an example embodiment in the process for preparing a cationic parenchymal cellulose the process further comprises concentrating the cationic parenchymal cellulose hydrogel obtained in the process. In an example embodiment in the process for preparing cationic parenchymal cellulose the process step e. is carried out and the cationic parenchymal cellulose hydrogel comprises or consists of the parenchymal cellulose derivative of the first aspect.

EXAMPLES The following examples are provided to illustrate various aspects of the present invention. They are not intended to limit the invention, which is defined by the accompanying claims.

Example 1. Purification of potato pulp

Dry dehydrated potato pulp was purified in a lye wash. Here, the potato pulp (solids 2500 g) was taken to a 25 g/L suspension and heated to 60-90°C. With gentle stirring, 20 g/L NaOH was added. During this time, the hydrated potato clippings lost their solid-like morphology and broke down into a dark brown viscous mass within a minute. After 120 minutes of stirring, the reaction was cooled down and filtrated through a steel screen (0.25 mm pore size). The lye-washed pale grey cellulosic potato mass was further washed with copious amounts of water.

Example 2. Purification of sugar beet pulp

Dry dehydrated sugar beet pulp was purified in a two-step process. Sugar beet clipping (2500 g) were taken to a 25 g/L suspension. The pH of the reaction suspension was set to 2, using 1.0 M HCI. The suspension of sugar beet pulp was heated to 60-90 degrees and gently stirred for 120 minutes. The ensuing beet clippings were filtered through a steel mesh screen (0.25 mm pore size) and further washed with copious amounts of deionized water. After the acid wash, the hydrated sugar beet pulp was washed in lye. Here, pulp was taken to a 25 g/L suspension and heated to 60-90°C. With gentle stirring, 20 g/L NaOH was added. During this time, the hydrated beet clippings lost their solid-like morphology and broke down into a dark brown viscous mass. After 120 minutes of stirring, the reaction was cooled down and filtrated through a steel screen (0.25 mm pore size). The lye-washed pale grey cellulosic sugar beet mass was further washed with copious amounts of water.

Example 3. Bleaching of potato pulp

After the washing procedure (see Example 1 ), the purified potato-based parenchymal cellulose was bleached using sodium chlorite (NaCIC>2). The purified potato pulp (solids: 1000 g) mass was taken up to a 25 g/L slurry, heated to 70-90°C and subsequently buffered to pH 4.9 with acetic acid. Then the NaCIC>2 powder (3.4 g/L, 136 g, 1 .5 mol) was stirred into the reaction. The reaction was then allowed to proceed without any stirring.

After three hours, the mass was filtered through a polyester mesh (pore size 0.5 mm). The ensuing bleached potato mass was further washed with copious amounts of deionized water. Example 4. Bleaching of sugar beet pulp

After the two-step washing procedure (see Example 2), the purified beet-based parenchymal cellulose was bleached using sodium chlorite (NaCIC>2). The purified sugar beet pulp (solids: 65.5 g) mass was taken up to a 25 g/L slurry, heated to 70-80°C and subsequently buffered to pH 4.9 with acetic acid. Then a NaCIC>2 powder (3.4 g/L, 8.9 g, 0.098 mol) was stirred into the reaction.

After three hours stirring, the slurry was filtered through a polyester mesh (pore size 0.5 mm). The ensuing bleached sugar beet mass was further washed with copious amounts of deionized water.

Example 5. Cationization of bleached potato pulp

The ensuing surface cationization was done to bleached potato pulp (see Example 3). Bleached potato pulp (solids 97,2 g) was taken to a 31 g/L dispersion (1000 mL). The pulp was activated by adding NaOH (156.2 g) and stirring the slurry at 60°C for 30 minutes. Next, glycidyltrimethylammonium chloride (1800 mL, 79% aqueous solution) was added and the reaction was stirred for 120 minutes. The exothermic reaction raised the reaction tempera- ture temporarily to 90°C. After 120 minutes, the reaction was cooled down and filtered with copious amounts of deionized water through a steel mesh (pore size 0.25 mm). The mass readily formed a hydrogel. Example 6. Cationization of bleached sugar beet pulp, high degree of substitution (D.S.)

The ensuing surface cationization was done to bleached sugar beet pulp (see Example 4). Bleached sugar beet pulp (solids 39.1 g) was taken to a 4.3 g/L dispersion (900 ml_). The pulp was activated by adding NaOH (45 g) and stirring the slurry at 60°C for 30 minutes. Next, glycidyltrimethylammonium chloride (1200 ml_, 70% aqueous solution) was added and the reaction was stirred for 120 minutes. The exothermic reaction raised the reaction temperature temporarily to 90°C. After 120 minutes, the reaction was cooled down and filtered with copious amounts of deionized water through a steel mesh (pore size 0.25 mm). The mass readily formed a hydrogel.

To determine the degree of cationization, the purified pulp was titrated against 0.1 M AgN03. According to conductiometric titration, the degree of substitution was approximately 0.25-30.

Example 7. Cationization of bleached sugar beet pulp, low D.S.

The ensuing surface cationization was done to bleached sugar beet pulp (see Example 4). Bleached sugar beet pulp (solids 37.3 g) was taken to a 37 g/L dispersion (1000 ml_). The pulp was activated by adding NaOH (1 g/mL, 50 g) and stirring the slurry at 60°C for 30 minutes. Next, glycidyltrimethylammonium chloride (600 ml_, 70% aqueous solution) was added and the reaction was stirred for 120 minutes. The exothermic reaction raised the reaction temperature temporarily to 90°C. After 120 minutes, the reaction was cooled down and filtered with copious amounts of deionized water through a steel mesh (pore size 0.25 mm). The mass readily formed a hydrogel.

To determine the degree of cationization, the purified pulp was titrated against 0.1 M AgN03. According to conductiometric titration, the degree of substitution was approximately 0.1.

Example 8. Fibrillation of cationized potato pulp.

The rheological properties could be further promoted by high-pressure homogenization of the chemically engineered pulp derivatives (see Examples 3 and 5). By running potato pulp based derivatized parenchymal dispersion (25 g/L) through a fluidizer (Microfluidics M-1 10) at 1800 bar 1 time, the rheological properties were promoted.

Example 9. Fibrillation of sugar beet pulp and its chemically modified derivatives. The rheological properties could be further promoted by fibrillation, i.e. high-pressure homogenization of the chemically engineered pulp derivatives (see Examples 6, 7). By running chemically engineered derivatives (25 g/L) through a fluidizer (Microfluidics M-1 10) at 1800 bar 1 time, the rheological properties were promoted. Example 10. Rheological characterization of fibrillated and non-fibrillated derivatized parenchymal cellulose based on potate pulp

Rheological measurements

The measurements were performed at 25 °C using a dynamic rotational rheometer (HR-2, TA Instruments). The geometry used was stainless steel concentric cylinders geometry, bob and cup radii 14.02 and 15.20 mm, fulfilling the standard ISO 3219/DIN 53019.

The measurement routine for fibrillated cellulose suspensions is presented in Table 1 The purpose of the peak hold and time sweep interval in between amplitude sweep, frequency sweep and both shear stress and shear rate controlled stepped flow intervals was to set a comparable shear history to the samples. The linear viscoelastic region was determined with an oscillatory amplitude sweep. Frequency sweep was performed to probe the fiber network structure at rest, and stepped flow curves were to characterize the flow properties of the suspensions. Shear stress controlled flow curve may be better able to reveal yielding in the suspension, whereas shear rate controlled flow curve is more directly linked to the flow rate, i.e. rate of deformation in the suspension structure.

Table 1 . Rheological measurement intervals.

short for point time, 15 s, of which the average of last 5 s recorded

Results. The rheological behavior of the cationically derivatized parenchymal cellulose sam- pies based on potato pulp is presented in Fig. 2 A-D. Fig. 2 A shows constant storage modulus (G') levels for both non-fibrillated and fibrillated cationic potato pulp samples at 0.5 wt% consistency, and Fig. 2B shows the calculated loss tangent (tan(8)). In common with both non-fibrillated and fibrillated cationic potato pulp samples, they exhibit gel like behavior: Storage modulus G' is constant over wide range of frequencies, and the tan(8) < 1 , i.e. the re- sponse is elastically dominated (storage modulus G' > loss modulus G"). Both samples are also markedly shear thinning in steady shear experiments (Fig. 2D) and show yield stress type of behavior (steady plateau in viscosity levels before the collapse at yield point, Fig. 2 C). Fibrillation enhances the gel structure as can be seen in elevated G' levels (Fig. 2A), elevated yield stress (Fig. 2C) and elevated viscosity levels (Fig. 2D). Higher G' for fibrillated sample compared to non-fibrillated sample indicates that gelations takes place at lower concentration. The structure of the samples was homogeneous, continuous gel structure without observable phase separation during the experiment or the preceding storage time.

Example 11. Rheological characterization of fibrillated and non-fibrillated derivatized parenchymal cellulose based on sugar beet

Rheological measurements The measurements were performed at 25 °C using a dynamic rotational rheometer (HR-2, TA Instruments). The geometry used was stainless steel concentric cylinders geometry, bob and cup radii 14.02 and 15.20 mm, fulfilling the standard ISO 3219/DIN 53019.

The measurement routine for fibrillated cellulose suspensions is presented in Table 2. The purpose of the peak hold and time sweep interval in between amplitude sweep, frequency sweep and both shear stress and shear rate controlled stepped flow intervals was to set a comparable shear history to the samples. The linear viscoelastic region was determined with an oscillatory amplitude sweep. Frequency sweep was performed to probe the fiber network structure at rest, and stepped flow curves were to characterize the flow properties of the sus- pensions. Shear stress controlled flow curve may be better able to reveal yielding in the suspension, whereas shear rate controlled flow curve is more directly linked to the flow rate, i.e. rate of deformation in the suspension structure.

Table 2. Rheological measurement intervals.

a) pt is short for point time, 15 s, of which the average of last 5 s recorded Results. The rheological behavior of the cationically modified sugar beet pulp samples with high D.S. is presented in Fig. 1 A-D, and with low D.S. in Fig. 3 A-D. Fig. 1 A shows constant G' levels for both non-fibrillated and fibrillated high D.S. cationic sugar beet pulp suspensions at 0.5 wt% consistency. Correspondingly, Fig. 1 B shows the calculated tan(8) fibrillated and fibrillated high D.S. cationic sugar beet pulp samples, they exhibit gel like behavior: G' is constant over wide range of frequencies, and the tan(8) < 1 , i.e. the response is elastically dominated (G' > G"). Both samples are also markedly shear thinning in steady shear experiments(Fig. 1 D) and show yield stress type of behavior (Fig. 1 C). Fibrillation enhances the gel structure as can be seen in elevated G' levels (Fig. 1A), elevated yield stress (Fig. 1 C) and elevated viscosity levels (Fig. 1 D). Higher G' for fibrillated sample compared to non- fibrillated sample indicates that gelations takes place at lower concentration. The structure of the samples was homogeneous, continuous gel structure without observable phase separation during the experiment or the preceding storage time. Low D.S cationic substitution in sugar beet pulp is already sufficient for gel forming, see Fig. 3 A (constant G') and FIG 3. B (tan(8) < 1 ). The gel structure is weaker than with high D.D. as inferred from the lower G' levels (compare Fig. 3A and Fig. 1A) and yielding at lower stress (the point where the viscosity collapses from the plateau level, compare Fig. 3C and Fig. 1 C). Also the viscosity as a given shear rate is lower (Fig. 3D vs. Fig. 1 D). The structure of the sugar beet pulp samples was homogeneous, continuous gel structure without observable phase separation during the experiment or the preceding storage time.

Example 12. Mechanical characterization of solvent cast films

Sample preparation

Materials were solvent cast as follows. Samples were diluted to a solid content suitable for solvent casting, typically 0.4-1 .0 wt.%, and degassed in vacuum to remove bubbles formed due to mixing. An amount containing 100 mg of solids was applied onto a plastic petri dish (diameter 50 mm). The samples were dried in an oven at 60°C until they appeared dry. The films were removed from the petri dishes, and the drying was continued for at least 4 h between blotting papers at a temperature above 100°C.

Tensile testing

The solvent-cast films were cut to 2 mm wide strips for mechanical testing. The thickness of each strip was measured using a Mitutoyo film thickness gauge. Thickness was measured at three points, and the average was used for data analysis. Before tensile testing, the samples were stored at a controlled humidity (RH 50%, 20°C) overnight. Tensile tests were performed using a Kammrath & Weiss tensile tester with a 100 N load cell. The grip separation in the starting position was 10 mm. Sample strips were elongated at 1 .00 mm/min, and the force and elongation were measured at a sampling frequency of 20 Hz. From each film, 5-6 strips were measured.

Tensile data analysis

Tensile strength, elastic modulus, strain (elongation) at break, and the modulus of toughness (i.e., the area under the stress-strain curve) were determined separately from each single measurement. The mean values for each property are tabulated together with the standard error of mean. An average curve was generated by calculating the average of stresses at each strain point until the average strain at break, linearly interpolating the measured data for each point. Before calculating the average curve, the data from the samples that broke before average were linearly extrapolated until the average strain at break.

Results

The tensile testing results are shown in Fig. 4, and the values are tabulated in Table 3. The samples had a tensile strength between 65 and 143 MPa, an elastic modulus between 2.6 and 7.4 GPa and a strain at break between 4.4 and 14.9%. The results show that for both starting materials, homogenization results in considerably increased tensile strength and reduced strain at break. Furthermore, in case of cationized potato pulp, homogenization also results in a large increase in elastic modulus.

Table 3. Mechanical properties with the standard error.

The foregoing description has provided, by way of non-limiting examples of particular implementations and embodiments of the invention, a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodi- merits presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

Furthermore, some of the features of the afore-disclosed embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

Example 13: cationic nanocellulose coating

A human hair (15-year-old Nordic female, blonde) was coated with cationic nanofibrillar cellulose (product from example 9) by immersing it into the gel at 0.2% solid content. The hair was removed after a few seconds and dried in ambient room conditions. 1 cm of the coated hair was mounted on carbon tape, sputtered with 5 nm of Au-Pd, and imaged using a Zeiss Sigma VP scanning electron microscope.

The electron microscopy image, see figure 5, reveals a thin layer of nanofibrillar cellulose attached on the surface of the hair, showing that the cationic compounds described in this invention can be used to modify hair surface. Properties such as combability, flyway, body and curl retention, to name just a few, are affected by the deposition of the cationic parenchymal nanofibrillar cellulose on the hair surface.

Claims

1 . A parenchymal cellulose derivative obtained by derivatizing parenchymal cellulose to comprise cationic substituents wherein the parenchymal cellulose derivative is capable of

5 forming a continuous gel from an aqueous dispersion at at least one point in a concentration range of from about 0.05 wt.% to about 99 wt.% based on total weight of the gel.

2. The parenchymal cellulose derivative of claim 1 capable of forming a continuous gel from an aqueous dispersion at at least one point in a concentration range of from about 0.1

10 wt.% to about 2 wt.% based on total weight of the gel.

3. The parenchymal cellulose derivative of claim 1 or 2 having a property of forming from an aqueous dispersion a film having a tensile strength higher than 40MPa.

4. The parenchymal cellulose derivative of any one of claims 1 -3 wherein the parenchymal cellulose comprises cellulose from sugar beet, bagasse, cassava, and/or potato.

15 5. The parenchymal cellulose derivative of any one of claims 1 -4 fibrillated to comprise nanofibrillar cellulose preferably having a number average diameter of 2-100nm, more preferably of 2-1 Onm.

6. The parenchymal cellulose derivative of claim 5 having a property of being capable of forming a film which has a tensile strength higher than before fibrillation.

20 7. The parenchymal cellulose derivative of claim 5 having a property of being capable of forming a gel which has an elastic modulus higher than before fibrillation.

8. Composition comprising nanofibrillar parenchymal cellulose derivative obtained by fibrillating the parenchymal cellulose derivative of any one of claims 1 -4.

9. Composition comprising the parenchymal cellulose derivative of any one of claims 1 -4.

25 10. A method of modifying rheological properties of a composition of matter, said method comprising the step of incorporating into said composition of matter the parenchymal cellulose derivative according to any one of claims 1 -7 or the composition of claim 8 or 9.

1 1 . A method of improving at least one of sizing, strength, scale control, drainage, dewatering, retention, clarification, formation, adsorbency, film formation, membrane

30 formation, and polyelectrolyte complexation during paper or board manufacture, said method comprising the step of using the parenchymal cellulose derivative according to any one of claims 1 -7 or the composition of claim 8 or 9.

12. A method for improving stability of an emulsion, suspension, dispersion, or foam system, said method comprising the step of including in the system the parenchymal cellulose derivative according to any one of claims 1 -7 or the composition of claim 8 or 9.

13. A process for preparing a cationic parenchymal cellulose gel, the process comprising: a. providing parenchymal cellulose and optionally hydrolyzing it with an acid and/or an alkali; b. recovering the cellulosic residue; c. cationizing the cellulosic residue; d. harvesting the cationic cellulose as a hydrogel; and, optionally e. fibrillating the hydrogel from step d. wherein the fibrillation is carried out to provide increased storage modulus compared to the non-fibrillated suspension.

14. The process of claim 13 wherein the parenchymal cellulose is selected from a group comprising any of: sugar beet, bagasse, cassava, and potato, the process further comprising bleaching the cellulosic material either before a. or after step b., d., or e.

15. The process of claim 13 or 14 further comprising concentrating the cationic parenchymal cellulose hydrogel.

16. The process of any one of claims 13-15 wherein step e. is carried out and the cationic parenchymal cellulose hydrogel comprises parenchymal cellulose derivative of any one of claims 1 -7.

17. A cationic parenchymal cellulose hydrogel obtained by the process according to any one of claims 13-16.

18. A hair conditioning composition comprising the parenchymal cellulose derivative of the parenchymal cellulose derivative according to any one of claims 1 -7, the composition of claim 8 or 9, or the cationic parenchymal cellulose hydrogel of claim 17.

19. A method for improving condition of hair, the method comprising a step of depositing the parenchymal cellulose derivative according to any one of claims 1 -7 or the composition of claim 8 or 9 on the hair surface.