NL2030399A

NL2030399A - High-strength biomass membrane material and preparation method thereof

Info

Publication number: NL2030399A
Application number: NL2030399A
Authority: NL
Inventors: Wang Hui; Yang Fuxian; Zhou Xiaojian; Zhang Jun; Wu Haizhu; Peng Jinda; Deng Shuangqi; Liao Jingjing; Du Guanben; Liao Dongsen
Original assignee: Univ Southwest Forestry
Priority date: 2021-06-30
Filing date: 2022-01-03
Publication date: 2022-05-04
Also published as: CN113321936A; NL2030399B1; CN113321936B

Abstract

The present disclosure belongs to the technical field of preparation of packaging materials, and particularly relates to a high-strength biomass membrane material and a preparation method thereof; specifically, casein is used as a substrate material, and casein is cross-linked and modified by using microcrystalline cellulose and tannin to obtain a protein membrane with excellent mechanical strength and elongation limit. The prepared membrane material is degradable, is good in comprehensive performance, haVing a wide application range.

Description

HIGH-STRENGTH BIOMASS MEMBRANE MATERIALAND PREPARATION METHOD THEREOF

TECHNICAL FIELD [DI] The present disclosure belongs to the technical field of preparation of packaging materials, and particularly relates to a high-strength biomass membrane material and a preparation method thereof.

BACKGROUND ART

[02] In the past decades, conventional non-degradable packaging materials have polluted the ecological environment and seriously threatened human health. According to statistics, more than 300 million tons of plastic wastes are generated every year across the world, of which about 79% wastes are backfilled in the nature, and food plastic packaging wastes account for a large proportion. In recent years, with the rapid development of take-out, express logistics, etc., the short-term consumption of plastic packaging bags has increased sharply, further increasing the impact on the environment.

[03] Green packaging materials are usually membranes with a grid structure formed by renewable raw materials through the interaction of different molecules. These biomass membranes can be completely degraded in the natural environment for a period of time without causing pollution to the environment. The rapid development of green packaging materials has a broad application prospects, mainly including cellulose derivatives, polyamides, polyesters, polyolefins, ethylene polymers, silicon-containing polymers and fluoropolymers, etc. Among them, the earliest and most used biomass membrane materials are cellulose membrane materials. Although biomass membrane materials have the advantages of being renewable, good biocompatibility, and completely degradable after being discarded, it is difficult for biomass membrane materials to simultaneously have good hydrophilicity, membrane-forming properties, thermal stability, anti-pollution, chemical stability, acid and alkali resistance, and good mechanical strength, etc. Therefore, it is necessary to modify the biomass membrane materials. The existing technologies mainly include chemical modification before membrane formation, graft copolymerization, and cross-linking, etc.; surface modification after membrane formation, such as plasma treatment, surface etching, surface chemical reaction, surface molecular assembly, surface physical coating, surface graft modification, etc.

[04] The patent document with the application number CN201110185437.3 discloses a method for preparing an edible casein preservative film and an application in barbecue. Among them, casein is used as the matrix material for film formation, and the casein is dissolved in water to react with other auxiliary materials through the hydrogen bond, hydrophobic bond, coordination bond, covalent bond, etc. in the molecules, to form a composite preservative film. However, this method is to dissolve casein and prepare the film-forming solution under acidic or weakly alkaline conditions. Although the prepared film has high tensile strength, the elongation limit is relatively limited, with the maximum of 20%.

[05] The patent document with the application number CN201611242806.7 discloses a novel polymer plastic film formulation and preparation process. The raw materials are composed of polyethylene, polypropylene, sodium carboxymethyl cellulose, oxidized polyethylene wax, vinyl ether, casein, montmorillonite powder, degradable material, degradable enzyme powder, lubricants, antioxidants, ultraviolet absorbers, foaming agents, acid-base regulators, microcrystalline paraffin. However, the degradation time required for polyethylene is very long. Under the premise of consuming a large amount of plastic packaging bags, the degradation time is too long, causing the consumption to be far greater than the degradation, which will also cause pressure on the environment.

SUMMARY

[06] In order to solve the above problem, the present disclosure provides a high- strength biomass membrane material and a preparation method thereof.

[07] The present disclosure is specifically realized by the following technical solution:

[08] 1. A high-strength biomass membrane material comprises the following components in parts by weight: 6 parts of casein, 0.5-3 parts of a modifier, 5-10 parts of an oxidant, 1-3 parts of a plasticizer and 100-200 parts of water.

[09] Further, the modifier is one or two of microcrystalline cellulose and tannin.

[10] Further, the dosage of the microcrystalline cellulose is 0.5-2 parts by weight, and the dosage of the tannin 1s 0-1 part by weight.

[11] Further, the oxidant is sodium periodate, and the plasticizer is glycerol.

[12] 2. A method for preparing the high-strength biomass membrane material specifically comprises the following steps:

[13] (1) dissolving microcrystalline cellulose in distilled water, adding an oxidant, mixing and stirring to obtain oxidized microcrystalline cellulose; and adding tannin, uniformly mixing, and stirring in a constant-temperature water bath at 50-80°C for 10- 30 min to obtain a modified reinforcement;

[14] (2) dissolving casein in an alkaline solution, adjusting the pH value of the system to 8-11, and uniformly stirring to obtain a substrate solution; and

[15] (3) uniformly mixing and stirring the modified reinforcement and substrate solution for 10 min, adding a plasticizer, heating to 60-80°C, stirring in a constant- temperature water bath for 20-40 min until the mixture becomes a resin membrane solution, cooling to remove foam, pouring into a mold, and casting to form the membrane.

[16] Further, the alkaline solution is specifically one or more of a sodium hydroxide solution, a potassium hydroxide solution, a calcium hydroxide solution and ammonia water.

[17] In summary, the present disclosure has the beneficial effects as follows: casein is used as the substrate raw material of the membrane material, and the casein is subjected to crosslinking modification treatment by adopting microcrystalline cellulose and tannin to obtain a protein membrane with excellent mechanical strength and elongation limit, and the prepared membrane material is degradable, good in comprehensive performance and wide in application range.

[18] Wherein, chemical bonds for maintaining a stable structure of the casein protein, such as hydrogen bonds, ionic bonds, disulfide bonds and hydrophobic bonds which interact, and dipole interaction, are broken, so that internal hydrophobic groups and sulfydryl of the protein are exposed on the surface to form new disulfide bonds; in an air-water interface, the hydrophobic groups of the protein extend into the air, and hydrophilic groups are retained in water, such that directionally arranged protein layers are formed on the horizontal plane to obtain the protein membrane with certain barrier property and mechanical strength; then the microcrystalline cellulose and the tannin are crosslinked with the protein membrane, and a polyphenol structure of the tannin can be combined with the protein through the hydrogen bonds, the hydrophobic bonds, the tonic bonds and covalent bonds, so the comprehensive performance of the membrane can be effectively improved, and the prepared membrane material has higher mechanical strength and tensile rate and also has certain oxidation resistance and antibacterial property. The selected raw materials are renewable, so the dependence on petrochemical products is reduced. The preparation process is simple and easy for industrialized production, and the prepared membrane material is high in mechanical strength, degradable and friendly to natural environment.

BRIEF DESCRIPTION OF THE DRAWINGS 19] FIG. 1 is a high-strength biomass membrane prepared by a method in example I.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[20] The specific embodiments of the present disclosure will be further described in detail below, but the present disclosure is not limited to these embodiments. Any improvement or substitution made without departing from the spirit of the embodiments shall fall within the scope of protection claimed by the claims of the present disclosure.

[21] Example 1

[22] I. A method for preparing a high-strength biomass membrane material specifically comprised the following steps:

[23] (1) weighing 1 g of microcrystalline cellulose, dissolving the microcrystalline cellulose in 50 ml of distilled water, adding 0.6 g of 6 mol/L sodium periodate solution, mixing and stirring for 2 h until the solution was uniform, to obtain oxidized 5 microcrystalline cellulose; weighing 0.3 g (10%) of tannin, and dissolving the tannin in 1 ml of distilled water; and uniformly mixing the oxidized microcrystalline cellulose with the tannin aqueous solution, placing the mixture in a constant-temperature water bath at 70°C, and stirring for reaction for 20 min to crosslink the mixture into a modified reinforcement;

[24] (2) dissolving 6 g of casein in 100 ml of distilled water, adjusting the pH value of the solution to 11 by using a sodium hydroxide solution, and violently stirring for about 0.5 hour until the solution was uniform to obtain a substrate solution; and

[25] (3) stirring the modified reinforcement and the substrate solution for 10 min, adding 3 g of glycerol, heating to a constant-temperature water bath at 80°C, and stirring for 20 min until the solution was uniform to obtain a resin membrane solution; and cooling and defoaming the prepared membrane solution, and pouring into a mold to form a membrane.

[26] Example 2

[27] I. A method for preparing a high-strength biomass membrane material specifically comprised the following steps:

[28] (1) weighing 1 g of microcrystalline cellulose, dissolving the microcrystalline cellulose in 50 ml of distilled water, adding 0.6 g of 6 mol/L sodium periodate solution, mixing and stirring for 2 h until the solution was uniform, to obtain oxidized microcrystalline cellulose; weighing 0.6 g (10%) of tannin, and dissolving the tannin in 2 ml of distilled water; and uniformly mixing the oxidized microcrystalline cellulose with the tannin aqueous solution, placing the mixture in a constant-temperature water bath at 60°C, and stirring for reaction for 10 to 30 min to crosslink the mixture into a modified reinforcement;

[29] (2) dissolving 6 g of casein in 100 ml of distilled water, adjusting the pH value of the solution to 8 by using a potassium hydroxide solution, and violently stirring for about 0.5 hour until the solution was uniform to obtain a substrate solution; and

[30] (3) stirring the modified reinforcement and the substrate solution for 10 min, adding 2 g of glycerol, heating to a constant-temperature water bath at 80°C, and stirring for 40 min until the solution was uniform to obtain a resin membrane solution; and cooling and defoaming the prepared membrane solution, and pouring into a mold to form a membrane.

[31] Example 3

[32] 1. A method for preparing a high-strength biomass membrane material specifically comprised the following steps:

[33] (1) weighing 1 g of microcrystalline cellulose, dissolving the microcrystalline cellulose in 50 ml of distilled water, adding 0.6 g of 6 mol/L sodium periodate solution, mixing and stirring for 2 h until the solution was uniform, to obtain oxidized microcrystalline cellulose; weighing 0. 9 (10%) of tannin, and dissolving the tannin in 2 ml of distilled water; and uniformly mixing the oxidized microcrystalline cellulose with the tannin aqueous solution, placing the mixture in a constant-temperature water bath at 60°C, and stirring for reaction for 10 to 30 min to crosslink the mixture into a modified reinforcement;

[34] (2) dissolving 6 g of casein in 100 ml of distilled water, adjusting the pH value ofthe solution to 10 by using an ammonia-water solution, and violently stirring for about

0.5 hour until the solution was uniform to obtain a substrate solution; and

[35] (3) stirring the modified reinforcement and the substrate solution for 10 min, adding 3 g of glycerol, heating to a constant-temperature water bath at 80°C, and stirring for 300 min until the solution was uniform to obtain a resin membrane solution; and cooling and defoaming the prepared membrane solution, and pouring into a mold to form a membrane.

[36] Comparative Example 1

[37] The membrane material was prepared using the raw material ratio and preparation method of Example 1, except that no modifier was added to oxidize microcrystalline cellulose and tannin.

[38] Comparative Example 2

[39] The membrane material was prepared using the raw material ratio and preparation method of Example 1, except that no modifier was added to oxidize microcrystalline cellulose.

[40] Comparative Example 3

[41] The membrane material was prepared using the raw material ratio and preparation method of Example 1, except that no tannin was added.

[42] Comparative Example 4

[43] The membrane material was prepared using the raw material ratio and preparation method of Examplel, with the difference that the added microcrystalline cellulose was not oxidized by sodium periodate, but the microcrystalline cellulose was directly mixed with tannin and then added to the casein solution.

[44] The tensile strength, expansion rate and water solubility of the membrane material prepared according to the Examples 1 to 3 and the Comparative Examples | to 4 were tested. The result was shown in Table 1.

[45] Table 1 Tensile ~ . | Water ro. rate {(¥0) rate {59} (MPa) (%) Comparative 20.25 432 32.7 or Comparative 25.58 222 27 Comparative 20.89 285 28.2 mews |]

[46] As shown in Table 1, the membrane material prepared by the method provided by the present disclosure had excellent mechanical properties; and compared with the comparative examples, the biomass membrane had higher tensile strength and elongation limit under the joint crosslinking action of the modifier oxidized microcrystalline cellulose and tannin; and the strength and tensile rate of the membrane obtained by the method provided by the examples were several times of the comparative examples, thus, the advantages were obvious.

Claims

-9.- Conclusions

1. High strength biomass membrane material comprising the following components by weight: 6 parts casein, 0.5 - 3 parts of a modifier, 5 - 10 parts of an oxidant, 1 - 3 parts of a plasticizer and 100 - 200 parts of water .

The high strength biomass membrane material of claim 1, wherein the modifier is one or two of microcrystalline cellulose and tannin.

The high strength biomass membrane material according to claim 2, wherein the dosage of the microcrystalline cellulose is 0.5 - 2 parts by weight, and the dosage of the tannin is 0 - 1 part by weight.

The high strength biomass membrane material of claim 1, wherein the oxidant is sodium periodate, and the plasticizer is glycerol.

A method for preparing the high-strength biomass membrane material, wherein the high-strength biomass membrane material is obtained by modifying casein with a modifier and then forming a film by cross-linking.

The method for preparing the high-strength biomass membrane material according to claim 5, wherein the modification treatment is to first oxidize the microcrystalline cellulose with an oxidizing agent, and after cross-linking reaction with tannin, mix it with casein to modify.

A method for preparing the high-strength biomass membrane material according to claim 5, specifically comprising the steps of: (1) dissolving microcrystalline cellulose in distilled water, adding an oxidant, mixing and stirring to give oxidized microcrystalline cellulose to obtain; and adding tannin, mixing evenly, and stirring in a constant temperature water bath at 50 — 80 °C for 10 — 30 minutes to

- 10 - to obtain modified gain; (2) dissolving casein in an alkaline solution, stirring evenly to obtain a substrate solution; and (3) mixing and stirring the modified reinforcement and substrate solution, adding a plasticizer, heating to 60 - 80°C, stirring in a constant temperature water bath until the mixture becomes a resin membrane solution, cooling to foam remove it, pour it into a mold, and pour it to form the membrane.

The method for preparing the high-strength biomass membrane material according to claim 7, wherein the basic solution is specifically one or more of a sodium hydroxide solution, a potassium hydroxide solution, a calcium hydroxide solution and ammonia water.