WO2021088527A1

WO2021088527A1 - Plant plastic and manufacturing method therefor

Info

Publication number: WO2021088527A1
Application number: PCT/CN2020/116019
Authority: WO
Inventors: 祝名伟; 吴佳扬; 黄大方; 陈延峰
Original assignee: 南京大学
Priority date: 2019-11-06
Filing date: 2020-09-18
Publication date: 2021-05-14
Also published as: CN112778578B; CN112778578A

Abstract

Disclosed are a plant plastic and a manufacturing method therefor. The plastic is only composed of micron plant fibers. The plant fibers are subjected to bending deformation and twisted tightly to form a dense microstructure. The appearance and property of the plant plastic are similar to those of the normal plastic. The plant plastic is optically translucent, and has hard texture, high strength, and a density (about 1.2-1.6 g/cm ³) approximate to the theoretical density of cellulose (about 1.6 g/cm ³). The component of the plant plastic is natural cellulose, has no thermoplasticity, and is fully biodegradable. The manufacturing method of the present invention comprises: treating the surface of the plant fibers by using a chemical solution; and then treating with acid or aqueous solution; and finally, using water to clean to remove the chemical residue in a sample, and drying to obtain the plant plastic. The plant plastic prepared in the present invention is a new material. The manufacturing method for the plant plastic has characteristics of wide source of raw materials, low cost, simple manufacturing steps, etc., and has a wide application range.

Description

Plant plastic and preparation method thereof

Technical field

The invention relates to a new plant plastic material and a preparation method thereof, and belongs to artificial microstructure materials, ecological materials and preparation techniques thereof.

Background technique

Plastic is an important product of petrochemical industry and one of the greatest inventions of mankind. However, due to the non-degradability of plastics, the so-called "plastic crisis" has been triggered in recent years with the increasing number of plastic waste. Plastic particles have been found not only on land but even in the deepest part of the ocean. Plastic not only causes environmental pollution, but even enters the human body in the form of water and aquatic animals, affecting human health. Therefore, looking for alternatives to plastics and developing new materials that are completely biodegradable and environmentally friendly are important guarantees for environmentally sustainable development. Natural cellulose is the most abundant natural polymer in nature. It has the advantages of low cost, renewable, environmentally friendly, and biodegradable. Therefore, the use of cellulose to prepare new materials has great scientific value and social significance.

Traditionally, people bond the plant fibers contained in natural plants through adhesive glue and other methods to form blocks with a certain strength, such as flooring and decoration wood panels. The addition of glue and other substances greatly affects its environmental friendliness. The use of environmentally friendly glues such as starch to bond the block material formed by plant fibers has a high cost and is prone to mildew. Another way is to dissolve all the plant fibers into nano-cellulose fibers, and then re-precipitate and solidify in the solution to obtain regenerated cellulose to obtain cellulose filaments or cellulose blocks. However, the preparation time and cost of extracting nanofibers from plants to form nanofibers are very high. At the same time, the time and cost of preparing block materials from nanofibers are also very high, which makes it difficult for the obtained materials to have production and application value.

The use of plant microfibers, that is, plant cells (such as papermaking fibers), to construct new materials with plastic functional properties will greatly reduce costs, making the resulting plant plastics possible to replace refractory plastics for large-scale applications. However, since the strong interaction between plant microfibers is difficult to achieve without the aid of foreign substances such as adhesive glue, it is not reported that pure plant microfibers form plastic-like materials.

Summary of the invention

The purpose of the present invention is to use micron-level plant fibers to prepare a new plant plastic material that is completely biodegradable and has excellent performance, so as to meet the environmentally friendly application of partially replacing plastics. Another object of the present invention is to provide a method for preparing the new material.

The technical scheme adopted by the present invention is:

A plant plastic composed of only micron-level plant fibers, the plant fibers are bent, deformed and tightly entangled to form a dense microstructure; the plant plastic has no thermoplasticity and can be completely biodegradable.

Further, the density of the plant plastic is 1.2-1.6 g/cm ³ , and the Shore hardness is 60-80.

Further, the micron-sized plant fibers are broken or non-broken plant cells.

The method for preparing plant plastics of the present invention includes the following steps:

(1) Treat the dispersed plant fibers with A treatment solution for a certain period of time to improve the surface activity of micron-level plant fibers;

(2) Treat with B treatment solution for a certain period of time to harden the plant fiber to form a block;

(3) The block material obtained in step (2) is washed with water to remove chemical residues, and the plant plastic can be obtained after drying.

Further, in step (1), the A treatment solution includes a strong alkali solution, an alkali/urea mixed solution, a lithium chloride/dimethylacetamide solution, an ionic liquid, a copper ammonia solution or N-methylmorpholine -N-oxide solution.

Further, in step (1), the certain treatment time is specifically 5 minutes to 72 hours.

Further, in step (2), the B treatment solution is a hydrochloric acid solution, an acetic acid solution, a sulfuric acid solution, a sodium hydroxide solution or water, or any safe combination of the above solutions.

Further, in step (2), the certain treatment time is specifically 1 minute to 72 hours.

The invention uses plant fibers as raw materials (such as paper-making fibers but not limited to paper-making fibers), and regulates the microstructure of the material by adjusting the form of the fibers to form a new material with new macroscopic properties. The advantages of the present invention are:

(1) The obtained plant plastic is composed only of plant fibers, does not contain any foreign substances, and has the appearance and mechanical properties of commonly used plastics.

(2) During the whole preparation process, there is no need to dissolve the cellulose fibers into nanofibers, and only the structure adjustment of the original plant fibers is performed, thereby retaining the properties of the plant fibers, greatly reducing costs and improving productivity.

(3) Plant fiber is a kind of green environmental protection material, and the source of its raw materials is very rich, which makes the preparation method of the present invention strong in operability.

(4) The preparation process has low cost, low energy consumption and time, and does not require mechanical pressure assistance.

(5) The plant plastic prepared by the present invention, as a completely biodegradable ecological new material with excellent performance, is expected to replace many plastic applications. Therefore, it is used in daily necessities, mechanical parts, military supplies, electrical insulation parts, and medical and health It has a wide range of application prospects in terms of supplies.

Description of the drawings

Figure 1 is a scanning electron micrograph of the surface morphology of the plant plastic prepared in Example 1;

Figure 2 is a photo of a block material of the plant plastic prepared in Example 1;

Figure 3 is the tensile strength of the plant plastic prepared in Example 1;

Figure 4 is a comparison of the hardness of the plant plastic prepared in Example 1 with commonly used plastics.

Detailed ways

Example 1:

Mix 10g of cellulose fiber from cotton with 7% NaOH, 12% urea aqueous solution, and stir it evenly. The volume of sodium hydroxide-urea aqueous solution required is 100ml. After freezing at -18°C for 1 hour, take it out. The shape changes from straight to distorted. The surface of the fiber is slightly dissolved, revealing the fresh surface. After taking it out, it is immersed in dilute hydrochloric acid for 10 hours, and then washed with deionized water several times, and then the washed sample is dried. During the dehydration process, the fiber Actively shrink to form a dense structure, and finally get a new plant plastic material. The scanning electron microscope image is shown in Figure 1. The plant plastic is composed of micron-sized plant fibers. The plant fibers are bent, deformed and tightly entangled to form a very dense structure.

It can be seen from Figure 2 that the plant plastic (white block) of this embodiment has an appearance similar to ordinary plastic, optically translucent, hard texture, high strength, and density (about 1.2-1.6g/cm ³ ) close to the theory of cellulose Density (about 1.6g/cm ³ ). The plant plastic is composed of natural cellulose, has no thermoplasticity, and can be completely biodegradable.

Example 2:

Mix 8g of cellulose fiber derived from wood with 7% NaOH and 12% urea aqueous solution, and stir it evenly. The volume of the required aqueous solution is 100ml. The resulting mixed system is frozen at -13°C for 3 hours, and the fiber shape From straight to twisted, the surface of the fiber is slightly dissolved, revealing the fresh surface. After taking it out, it is immersed in dilute sulfuric acid for 72 hours, then washed with deionized water, and then the cleaned sample is dried. During the dehydration process, the fiber shrinks actively. A dense structure is formed, and finally plant plastic is obtained.

Example 3:

10g of cellulose fiber derived from rice straw was mixed with lithium chloride/DMAc=8g: 100ml solution, and after reacting at a temperature of 140°C for 30 minutes, the resulting mixed system was allowed to stand for 10 hours. The surface of the cellulose was slightly dissolved, revealing fresh The surface is cleaned with deionized water several times, and then the cleaned sample is dried, and finally the vegetable plastic is obtained.

Example 4:

Mix 20 g of cellulose fibers derived from bamboo with 150 g of 1-butyl-3-methylimidazole hydrochloride ionic liquid, and then react and treat at a temperature of 100°C under a pressure of 1 MPa for 1 hour. At this time, the fibers swell and twist. The surface is slightly dissolved. The fresh surface is exposed, and after standing for 30 minutes, it is washed with deionized water several times, and then the washed sample is dried. The sample shrinks actively to form a dense structure, and finally a plant plastic is obtained.

Example 5:

Mix 20g of cellulose fiber derived from wheat straw with 7% NaOH and 12% urea aqueous solution, and stir well. The volume of sodium hydroxide-urea aqueous solution required is 160ml. After freezing at -15°C for 2 hours, take it out. During this process, the fiber swells and twists the spiral, the fiber surface is slightly dissolved, and the fresh surface is exposed. After taking it out, it is immersed in hydrochloric acid for 48 hours, and then washed with deionized water several times, and then the cleaned sample is dried. The fiber shrinks actively during the drying process. A dense structure is formed, and finally plant plastic is obtained.

Example 6:

Mix 10g of cellulose fiber from cotton with 7% NaOH, 12% urea aqueous solution, and stir it evenly. The required volume of sodium hydroxide urea aqueous solution is 110ml, and it will be taken out after freezing at -18°C for 10 minutes. The fiber swells and twists the spiral, the fiber surface is slightly dissolved, and the fresh surface is exposed. After taking it out, it is immersed in dilute sulfuric acid for 2 minutes, and then washed with deionized water for several times, and then the cleaned sample is dried. At this time, the sample shrinks actively to form a compact Structure, and finally get plant plastic.

Example 7:

Mix 100g of cellulose fiber derived from vines with 7% NaOH and 12% urea aqueous solution, and stir it evenly. The volume of the required aqueous solution is 1000ml. Frozen at -13°C for 24 hours. At this time, the fiber swells and spirals. Distorted, the fiber surface is slightly dissolved, and the fresh surface is exposed. After taking it out, it is immersed in acetic acid for 50 hours, and then washed with deionized water several times, and then the cleaned sample is dried. At this time, the sample actively shrinks to form a dense structure, and finally the plant is obtained. plastic.

Example 8:

Mix 10g of cotton-derived cellulose fiber with copper ammonia solution and stir it evenly. The Cu/NH ₃ molar ratio in the solution is 0.046/0.36, and 50ml of copper ammonia solution is required. Treat the resulting mixed system for 1 hour, and then take it out Immerse in a 10% NaOH solution for 10 hours. At this time, the fiber is twisted and twisted, and the fiber surface is slightly dissolved. Then, it is washed with deionized water several times, and then the cleaned sample is dried. When drying, the sample actively shrinks to form a dense structure, and finally Get plant plastic.

Example 9:

Mix 10g of cotton-derived cellulose fiber with 87% 150ml NMMO solution and stir well, react for two hours at a temperature of 120°C, the fiber swells, the fiber surface is slightly dissolved, and the fresh surface is exposed. After taking it out, it is immersed in deionized water After 70 hours, rinse with deionized water several times, and then dry the cleaned sample. At this time, the sample actively shrinks to form a dense structure, and finally a plant plastic is obtained.

Example 10:

Mix 10g of cotton-derived cellulose fibers with 18% NaOH strong alkali solution and stir them evenly. 30ml of strong alkali solution is required. Treat the resulting mixed system for 20 hours. At this time, the fibers swell and the fibers are twisted in a spiral shape. Entangling each other, immersing in hydrochloric acid for 1 hour after taking it out, and then washing with deionized water several times, and then drying the cleaned sample. When drying, the sample actively shrinks to form a dense structure, and finally a plant plastic is obtained.

Claims

A plant plastic, characterized in that the plastic is only composed of micron-level plant fibers, the plant fibers are bent, deformed and tightly entangled to form a dense microstructure; the plant plastic is non-thermoplastic and can be completely biodegradable.
The plant plastic of claim 1, wherein the plant plastic has a density of 1.2-1.6 g/cm 3 and a Shore hardness of 60-80.
The plant plastic according to claim 1 or 2, wherein the micron-sized plant fibers are broken or non-broken plant cells.
The method for preparing plant plastics according to claim 1, wherein the method comprises the following steps:

(1) Treat the dispersed plant fibers with A treatment solution for a certain period of time to improve the surface activity of micron-level plant fibers;

(2) Treat with B treatment solution for a certain period of time to harden the plant fiber to form a block;

(3) The block material obtained in step (2) is washed with water to remove chemical residues, and the plant plastic can be obtained after drying.
The method for preparing plant plastics according to claim 4, characterized in that, in step (1), the A treatment solution comprises a strong alkali solution, an alkali/urea mixed solution, lithium chloride/dimethyl ethyl Amide solution, ionic liquid, copper ammonia solution or N-methylmorpholine-N-oxide solution.
The method for preparing plant plastics according to claim 4, characterized in that, in step (1), the treatment time is specifically 5 minutes to 72 hours.
The method for preparing plant plastics according to claim 4, wherein in step (2), the B treatment solution is a hydrochloric acid solution, an acetic acid solution, a sulfuric acid solution, a sodium hydroxide solution or water, or more Any safe combination of solutions.
The method for preparing plant plastics according to claim 4, characterized in that, in step (2), the treatment time is specifically 1 minute to 72 hours.