WO2021017031A1 - Nanoscale plant fiber modified biodegradable composite material, preparation method therefor, and application thereof - Google Patents

Abstract

A preparation method for a nanoscale plant fiber modified biodegradable composite material and an application. The preparation method comprises the following steps: (1) grinding a dried plant fiber to obtain a nanoscale plant fiber; (2) adding the nanoscale plant fiber from step (1), polylactic acid, biodegradable copolyester, a compatibilizer, a plasticizer, and a tackifier into a blender in proportion for uniformly mixing to obtain a mixed material; and (3) adding the mixed material that is uniformly mixed into a twin-screw extruder, and performing extrusion granulation to obtain the nanoscale plant fiber modified biodegradable composite material. By using the nanoscale plant fiber and collaborating with the synergetic effect of the biodegradable copolyester, the compatibilizer, the plasticizer, the tackifier, polylactic acid, and the like, a biodegradable plastic is modified and product costs are reduced, so that a plastic product is fully degraded after use, the plant fiber is recycled and product costs are reduced.

Description

Nano-level plant fiber modified biodegradable composite material and preparation method and application thereof

【cross reference】

This application is based on the Chinese invention patent application filed on July 29, 2019 with the application number 2019106905467, titled "a nano-level plant fiber modified biodegradable composite material and its preparation method and application", and requires it priority.

【Technical Field】

The invention relates to the field of biodegradable technology, in particular to a nano-level plant fiber modified biodegradable composite material and a preparation method and application thereof.

【Background technique】

At present, the application of plastics in real life is ubiquitous, and the harm to the environment caused by its difficult to degrade is obvious to all. As the public's awareness of environmental protection has increased, degradable plastics have been used to protect the human living environment. At present, degradable plastic polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), polyhydroxy fatty acid ester (PHA), poly-β-hydroxybutyric acid (PHB), polymethyl ethylene carbonate Ester (PPC) has begun to be popularized and applied, but due to the high cost of materials, it is still lack of competitiveness in specific applications.

At present, there are mainly two types of modified degradable plastics modified by starch and calcium carbonate. Compared with ordinary plastics, starch modified plastics have the main disadvantages of poor water resistance, poor wet strength, and greatly reduced mechanical properties when exposed to water. Compared with ordinary plastics, calcium carbonate modified plastics are greatly reduced in transparency and brightness, especially not suitable for food packaging, which is difficult for users to accept.

Biodegradable plastics contain high technical content, so the required cost is also high. At present, the price of biodegradable plastic products on the market is more than double that of ordinary plastic products, and some of them are completely degradable by 2 to 8 times.

Polylactic acid degradable plastic is a kind of biodegradable plastic with good biodegradation effect. However, under natural environmental conditions, it will not be easily degraded when the corresponding microorganisms are lacking. In addition, due to its brittleness and high material market price, it is urgently needed Modify and reduce the price of raw materials.

[Content of the invention]

Based on this, it is necessary to provide a preparation method and application of a nano-scale plant fiber modified biodegradable composite material in response to the above technical problems.

In order to solve the above technical problems, the present invention provides a preparation method and application of a nano-scale plant fiber modified biodegradable composite material, which adopts the following technical solutions:

A preparation method of nano-level plant fiber modified biodegradable composite material, which comprises the following steps:

(1) Grind the dried plant fibers to obtain nano-level plant fibers;

(2) Add the nano-scale plant fiber, polylactic acid, biodegradable copolyester, compatibilizer, plasticizer and tackifier of step (1) to the high-speed mixer according to the following raw material ratios and weigh them together for uniformity Mixed into a mixture;

(3) Add the uniformly mixed mixture into the twin-screw extruder, extrude the mixture at a preset extrusion temperature, and pelletize to obtain the nano-scale plant fiber modified biodegradable composite material;

The nano-scale plant fiber modified biodegradable composite material is made by mixing the following raw materials in proportions, and the proportions are weight ratios:

Polylactic acid 5～30%

Biodegradable copolyester 20～70%

Compatibilizer 5～20%

Plasticizer 5～15%

Tackifier 5～15%

Nano-scale plant fiber 10-50%.

A nano-level plant fiber modified biodegradable composite material is prepared by the above-mentioned preparation method.

A disposable tableware is made of the above-mentioned nano-level plant fiber modified biodegradable composite material.

A composite material package is made of the above-mentioned nano-level plant fiber modified biodegradable composite material.

Compared with the prior art, the present invention has the following beneficial effects:

The invention uses a grinder to grind the dried commercially available plant fiber powder in multiple stages to achieve nanometer fineness, and at the same time cooperate with the synergistic effect of biodegradable copolyester, compatibilizer, plasticizer, tackifier, polylactic acid, etc. , To modify the biodegradable plastics and reduce product costs, so as to facilitate the full degradation of plastic products after use, and at the same time enable the reuse of agricultural and sideline products to reduce product costs.

The raw material prices of degradable plastics, polylactic acid and copolyester, are basically more than twice that of ordinary plastics such as PE. Nano-level plant fibers can be modified to reduce costs by 30-50%. After processing, the finished product has better processing performance and the final product has the same weight. The lower quantity is 30% higher than that of ordinary plastics. Compared with traditional plastic products, the price is at a level, and the competitiveness is greatly improved. However, the existing starch-modified degradable plastics have excessive water absorption (at least 20% water absorption). The problem of decreased stability, these shortcomings are exactly what the biodegradable composite material modified by the plant fiber of the present invention does not have, and the brightness and tensile properties of the biodegradable composite product modified by the nano-level plant fiber of the present invention are also better than the present. The degradable plastic modified by calcium carbonate is very suitable for food packaging materials and disposable food tableware.

The biodegradable composite material modified by nanometer plant fiber has better degradation performance. Nano-scale plant fibers have a promoting effect on the degradation of polylactic acid and biodegradable copolymers. In the soil-buried degradation test in the natural environment, after 30 days of degradation, the composite material of the present invention is degraded compared to the degradation system without adding nano-scale plant fibers. The degradation rate of the composite material of the present invention is increased by 1.97 to 4.97 times compared with the degradation system modified by adding micron-level plant fibers. This is an unexpected result in the test process of this application. Outside the effect. The biggest advantage of the present invention is that it is buried in farmland or flower pond under natural conditions, and the buried soil can be completely decomposed in about three months with a thickness of 10 cm, return to nature, simple return method, saving a lot of manpower and material resources, and environmental protection.

【Detailed ways】

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not All examples. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Most of the degradable plastics that have been promoted on the market are starch modified plastics and calcium carbonate modified plastics. The former has poor wet strength and greatly reduces its mechanical properties when exposed to water, while the addition of the latter greatly reduces the transparency of the original plastic, which greatly limits its application. Polylactic acid degradable plastic is a kind of biodegradable plastic with good biodegradation effect. However, under natural environmental conditions, it will not be easily degraded when the corresponding microorganisms are lacking. In addition, due to its brittleness and high material market price, it is urgently needed Modify and reduce the price of raw materials.

In order to solve the above technical problems, the present invention provides a nano-scale plant fiber modified biodegradable composite material, specifically, it is formed by mixing the following raw materials in proportions, and the proportions are weight ratios:

A preparation method of nano-level plant fiber modified biodegradable composite material, which comprises the following steps:

(1) Grind the dried plant fibers to obtain nano-level plant fibers;

(2) Add the nano-scale plant fiber, polylactic acid, biodegradable copolyester, compatibilizer, plasticizer and tackifier of step (1) to the high-speed mixer according to the following raw material ratios and weigh them together for uniformity Mixed into a mixture;

(3) Add the uniformly mixed mixture into the twin-screw extruder, extrude the mixture at a preset extrusion temperature, and pelletize to obtain the nano-scale plant fiber modified biodegradable composite material;

The nano-scale plant fiber modified biodegradable composite material is made by mixing the following raw materials in proportions, and the proportions are weight ratios:

Polylactic acid 5～30%

Biodegradable copolyester 20～70%

Compatibilizer 5～20%

Plasticizer 5～15%

Tackifier 5～15%

Nano-scale plant fiber 10-50%.

Polylactic acid (PLA) is a natural biodegradable plastic that has been industrialized. Polylactic acid has excellent optical properties and high modulus, but its breaking elongation, tear strength and breaking strength are low. In order to overcome these shortcomings, it is often co-extruded with other polymers to achieve the purpose of modification.

The plant fiber is selected from natural plant fiber materials, such as wood chips, bamboo chips, fruit husks, rice husks, wheat husks, peanut husks, soybean husks, bagasse, rice straws, wheat straws, sorghum stalks, cotton stalks, hemp stalks, corn cobs At least one of flour, bean curd residue, etc. The above-mentioned plant fiber is an agricultural by-product and is a natural organic substance. Its components are cellulose, hemicellulose, lignin, etc., which are converted into organic fertilizers under natural conditions and have a wide range of sources.

As an improvement of the plant fiber modified biodegradable composite material provided by the present invention, the biodegradable copolyester is polybutylene succinate PBS, poly(butylene adipate and Copolymer of butylene terephthalate) PBAT or poly(copolymer of butylene succinate and butylene adipate) PBSA or a mixture of one or more. The biodegradable copolyester is blended with polylactic acid to improve the brittleness of polylactic acid.

As an improvement of the plant fiber modified biodegradable composite material provided by the present invention, the compatibilizer is glycidyl methacrylate (GMA), oligomeric epoxy chain extender, ethanolamine and titanium One or more mixtures of tetrabutyl acid. The addition of the compatibilizer improves the compatibility of the mixture and facilitates mixing and processing.

As an improvement of the plant fiber modified biodegradable composite material provided by the present invention, the plasticizer is epoxy soybean oil, white oil, glycerin, polyethylene glycol, citric acid, and phthalic acid One or more mixtures of dimethyl ester and acetylated triethyl citrate (ATBC).

As an improvement of the plant fiber modified biodegradable composite material provided by the present invention, the tackifier is maleic anhydride (MAH), which has a tackifying effect during the mixing process.

In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application are described clearly and completely below.

The following are specific embodiments of the present invention. The raw materials, equipment, etc. used in the following embodiments can be obtained through purchase except for special restrictions.

Example 1

A plant fiber modified biodegradable composite material, which is formed by mixing the following raw materials in proportions, and the proportions are weight ratios: polylactic acid 5%, poly(butylene adipate and butylene terephthalate) Alcohol ester copolymer) 60%, acetyl tri-n-butyl citrate 5%, glycidyl methacrylate 5%, maleic anhydride 15%, nanometer plant fiber 10%;

The preparation method of the plant fiber modified biodegradable composite material includes the following steps:

(1) Grind the dried plant fibers to obtain nano-level plant fibers; the plant fibers are commercially available corn cob flour;

(2) Combine the nano-scale plant fibers of step (1), polylactic acid, poly(butylene adipate-butylene terephthalate copolymer), acetyl tri-n-butyl citrate, methacrylic acid Glycidyl ester and maleic anhydride are weighed in the above-mentioned weight percentage ratio and then added to a high-speed mixer for uniform mixing to obtain a mixture;

(3) The above-mentioned homogeneously mixed mixture is added to the twin-screw extruder, and the mixture is extruded at a certain extrusion temperature (170-220°C) to obtain the nano-scale plant fiber modified biological Degrade composite materials.

In specific applications, the nano-level plant fiber modified biodegradable composite material is reprocessed by blown film according to different purposes, and various disposable tableware (such as straws) or packaging materials (such as food preservation bags).

Example 2

A plant fiber modified biodegradable composite material, which is formed by mixing the following raw materials in proportions, and the proportions are by weight: polylactic acid 15%, polybutylene succinate 10%, poly(adipic acid Butylene glycol ester and butylene terephthalate copolymer) 20%, dimethyl phthalate 10%, tetrabutyl titanate 20%, maleic anhydride 5%, and nanometer plant fiber 20%.

The preparation method of the plant fiber modified biodegradable composite material includes the following steps:

(1) Grind the dried plant fiber to obtain nano-level plant fiber; the plant fiber is a commercially available mixture of wood chips and bamboo chips;

(2) Combining the nano-scale plant fiber of step (1), polylactic acid, poly(butylene adipate co-butylene terephthalate copolymer), dimethyl phthalate, tetrabutyl titanate Butyl ester and maleic anhydride are weighed in the above-mentioned weight percentage ratio and then added to the high-speed mixer for uniform mixing to obtain a mixture;

(3) The above-mentioned homogeneously mixed mixture is added to the twin-screw extruder, and the mixture is extruded at a certain extrusion temperature (170-220°C) to obtain the nano-scale plant fiber modified biological Degrade composite materials.

In specific applications, the nano-level plant fiber modified biodegradable composite material is reprocessed by blown film according to different purposes to make various disposable tableware (such as straws) or packaging materials (such as food preservation bags).

Example 3

A plant fiber modified biodegradable composite material, which is formed by mixing the following raw materials in proportions, and the proportions are weight ratios: polylactic acid 15%, poly(butylene succinate and butylene adipate) Alcohol ester copolymer) 20%, epoxy soybean oil 5%, glycidyl methacrylate 5%, maleic anhydride 5%, nano-level plant fiber 50%.

The preparation method of the plant fiber modified biodegradable composite material includes the following steps:

(1) Grind the dried plant fibers to obtain nano-level plant fibers; the plant fibers are commercially available rice straws;

(2) Combine the nano-scale plant fibers of step (1), polylactic acid, poly(butylene adipate and butylene terephthalate copolymer), epoxy soybean oil, glycidyl methacrylate Weigh with maleic anhydride in the above weight percentage ratio and then add them to a high-speed mixer for uniform mixing to obtain a mixture;

(3) The above-mentioned homogeneously mixed mixture is added to the twin-screw extruder, and the mixture is extruded at a certain extrusion temperature (170-220°C) to obtain the nano-scale plant fiber modified biological Degrade composite materials.

In specific applications, the nano-level plant fiber modified biodegradable composite material is reprocessed by blown film according to different purposes, and various disposable tableware (such as straws) or packaging materials (such as food preservation bags).

Example 4

A plant fiber modified biodegradable composite material, which is formed by mixing the following raw materials in proportions, and the proportion is a weight ratio: polylactic acid 30%, poly(butylene adipate-butylene terephthalate) Alcohol ester) 20%, polyethylene glycol 5%, ethanolamine 5%, maleic anhydride 5%, nanometer plant fiber 35%.

The preparation method of the plant fiber modified biodegradable composite material includes the following steps:

(1) Grind the dried plant fibers to obtain nano-scale plant fibers; the plant fibers are a commercially available mixture of rice husk, wheat husk and peanut husk;

(2) The nano-scale plant fiber, polylactic acid, poly(butylene adipate and butylene terephthalate copolymer), polyethylene glycol, ethanolamine and maleic anhydride of step (1) The above weight percentages are weighed and then added to a high-speed mixer for uniform mixing to obtain a mixture;

(3) The above-mentioned homogeneously mixed mixture is added to the twin-screw extruder, and the mixture is extruded at a certain extrusion temperature (170-220°C) to obtain the nano-scale plant fiber modified biological Degrade composite materials.

In specific applications, the nano-level plant fiber modified biodegradable composite material is reprocessed by blown film according to different purposes to make various disposable tableware (such as knives, forks, lunch boxes, straws, etc.) or packaging materials (such as food preservation Film, packaging bag).

Comparative example 1

Based on Example 1, the difference from Example 1 is that the corncob flour is micron-sized corncob flour.

Comparative example 2

Based on Example 1, the difference from Example 1 is that without adding corn cob flour, the polylactic acid is 15%.

Effect evaluation and performance testing

Experiment 1: Physical and chemical performance testing

The plant fiber modified biodegradable composite material of Example 1-4 and the biodegradable material of Comparative Example 1-2 were put into an injection molding machine to make moldings. The injection molding machine was set at 160T, the sol temperature was 130-150°C, and the rate of fire was 2 Under the working condition of -4s, it is injected into a spline for performance testing.

Table 1 Physicochemical performance test results

From the performance test results of Examples 1 to 4 and Comparative Examples 1 and 2, it can be seen that adding nano-scale plant fibers to the biodegradable composite material has little effect on the mechanical properties of the biodegradable composite material, indicating that the addition of nano-scale plant fibers The latter biodegradable composite material still has good mechanical properties. The water absorption rate of the biodegradable composite material added with nano-scale plant fiber is higher than that of pure biodegradable material. This may be caused by the plant fiber having easy water absorption components such as cellulose, but the water absorption rate of the biodegradable composite material of the present invention is also controlled Within 1%, compared with the existing starch-modified degradable plastics, there is a problem that the water absorption rate is too high (the water absorption rate is at least 20%) and the stability thereof is reduced. These problems are precisely the biodegradable composite modified by the plant fiber of the present invention. There is no material.

Furthermore, the film products such as packaging bags made by blowing the biodegradable composite materials modified with nanometer-level plant fibers in Examples 1-4 of the present invention have the characteristics of gloss and high brightness, which solves the problem of the existing calcium carbonate modification The problem of low brightness of degradable plastics; while the film products, such as packaging bags, blown out of the biodegradable composite material of Comparative Example 1 have poor gloss, low brightness, and powder precipitation on the surface; therefore, the embodiment of the present invention The biodegradable composite material modified by 1-4 nanometer plant fiber not only has good gloss and high brightness, but also does not have any powder precipitation, which shows that nanometer plant fiber and biodegradable plastic have good fusion. The invention also solves the problem that the plant fiber powder purchased on the market is actually difficult to mix with polylactic acid due to its large particle size. Even if the particle size is reprocessed and ground to a smaller size, the film after being mixed into a masterbatch and blow molded There will be a problem of powder seepage.

Experiment 2: Degradation performance detection

The plant fiber modified biodegradable composite material of Examples 1-4 and the biodegradable material of Comparative Example 1-2 were blown and reprocessed into packaging bags and then tested for degradation performance.

The degradation performance of the composite material of the present invention is evaluated using a soil-buried biodegradation experiment (this biodegradation experiment adopts a relatively simple outdoor soil burial method, the soil used is ordinary flower pond soil, and the soil burial depth is about 10 cm. After the degradation experiment starts, it is added every 10 days. A certain amount of water, keep it moist. After the first batch of soil is buried for 30 days, take out the sample, rinse off the surface soil and dry it in an oven at 50°C for 24 hours, and then calculate the weight loss rate). The experimental results are shown in Table 2. .

Table 2

To	Example 1	Example 2	Example 3	Example 4	Comparative example 1	Comparative example 2
Original weight g	18.45	18.26	18.37	18.05	17.95	18.35
Final weight g	14.99	13.38	9.32	11.99	16.34	18.18
Weight loss rate%	18.75%	26.74%	49.28%	33.58%	8.97%	0.91%

Note: The packaging bag made in Comparative Example 1 has a non-smooth surface and nano-level plant fibers are precipitated and cannot be used.

From the degradation test results of Examples 1 to 4 and Comparative Examples 1 and 2, it can be seen that in the soil-buried degradation test in the natural environment, when the degradation is 30 days, compared with the degradation system without adding nano-scale plant fiber, the composite material of the present invention The degradation rate of the composite material is increased by 20.26 to 51.11 times. Compared with the degradation system modified by adding micron-scale plant fibers, the degradation rate of the composite material of the present invention is increased by 1.97 to 4.97 times. This is the test process of this application. An unexpected effect.

90 days after the second batch of soil was buried, check the degradation. There are still some residual packaging bags in the buried areas of Examples 1 and 2, and the weight loss rates are 86.34% and 89.48%, respectively. Only a small amount remains in the buried area of Example 4. The weight loss rate of the packaging bag is 96.55%. The packaging bag is no longer found in the buried area of Example 3 and is completely degraded; while the soil buried area of Comparative Example 1 has about half of the packaging bags, and the weight loss rate is 49.22%; There are still a large number of packaging bags in the soil-buried area of Comparative Example 2, and the measured weight loss rate is 7.14%. The main reason is that the composite material without corncob flour actually has a long degradation process, and the degradation conditions affect humidity, temperature, The requirements for microorganisms are higher.

The beneficial effects of the invention

The invention uses a grinder to grind the dried commercially available plant fiber powder in multiple stages to achieve nanometer fineness, and at the same time cooperate with the synergistic effect of biodegradable copolyester, compatibilizer, plasticizer, tackifier and polylactic acid , The modification of biodegradable plastics and the reduction of product costs, in order to facilitate the full degradation of plastic products after use, and at the same time enable the reuse of plant fiber powder, an agricultural by-product, to reduce product costs.

The raw material prices of degradable plastics, polylactic acid and copolyester, are basically more than twice that of ordinary plastics such as PE. Nano-level plant fibers can be modified to reduce costs by 30-50%. After processing, the finished product has better processing performance and the final product has the same weight. The lower quantity is 30% higher than that of ordinary plastics. Compared with traditional plastic products, the price is at a level, and the competitiveness is greatly improved. However, the existing starch-modified degradable plastics have excessive water absorption (at least 20% water absorption). The problem of decreased stability, these shortcomings are exactly what the biodegradable composite material modified by the plant fiber of the present invention does not have, and the brightness and tensile properties of the biodegradable composite product modified by the nano-level plant fiber of the present invention are also better than the present. The degradable plastic modified by calcium carbonate is very suitable for food packaging materials and disposable food tableware.

The biodegradable composite material modified by nanometer plant fiber has better degradation performance. Nano-scale plant fibers have a promoting effect on the degradation of polylactic acid and biodegradable copolymers. In the soil-buried degradation test in the natural environment, after 30 days of degradation, the composite material of the present invention is degraded compared to the degradation system without adding nano-scale plant fibers. The degradation rate of the composite material of the present invention is increased by 1.97 to 4.97 times compared with the degradation system modified by adding micron-level plant fibers. This is an unexpected result in the test process of this application. Outside the effect. The biggest advantage of the invention is that it is buried in farmland and flower ponds under natural conditions, and the buried soil can be completely decomposed with a thickness of 10 cm in about three months, returning to nature, simple returning methods, saving a lot of manpower and material resources, and being environmentally friendly.

Obviously, the embodiments described above are only a part of the embodiments of the present application, rather than all of the embodiments. The drawings show preferred embodiments of the present application, but do not limit the patent scope of the present application. This application can be implemented in many different forms. On the contrary, the purpose of providing these examples is to make the understanding of the disclosure of this application more thorough and comprehensive. Although this application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it is still possible for those skilled in the art to modify the technical solutions described in each of the foregoing specific implementations, or equivalently replace some of the technical features. . All equivalent structures made using the contents of the description and drawings of this application, directly or indirectly used in other related technical fields, are similarly within the scope of patent protection of this application.

Claims (10)

1. A preparation method of nano-level plant fiber modified biodegradable composite material, which is characterized in that it comprises the following steps:

   (1) Grind the dried plant fibers to obtain nano-level plant fibers;

   (2) In terms of weight percentage, combine 10-50% of nano-scale plant fibers, 20-70% of biodegradable copolyester, 5-20% of compatibilizer, 5-15% of plasticizer and 5～ 15% tackifier is added to the high-speed mixer and mixed uniformly to obtain a mixture;

   (3) The uniformly mixed mixture is added to the twin-screw extruder, the mixture is extruded at a preset extrusion temperature, and pelletized to obtain a nano-scale plant fiber modified biodegradable composite material.
2. The method for preparing nano-scale plant fiber modified biodegradable composite material according to claim 1, wherein the biodegradable copolymer is polybutylene succinate, poly(butylene adipate) Ester and butylene terephthalate copolymer) or poly(butylene succinate and butylene terephthalate copolymer) or a mixture of several.
3. The nano-scale plant fiber modified biodegradable composite material according to claim 1, wherein the compatibilizer is glycidyl methacrylate, oligomeric epoxy chain extender, ethanolamine and titanate One or more mixtures of butyl esters.
4. The method for preparing nano-scale plant fiber modified biodegradable composite material according to claim 1, wherein the plasticizer is epoxy soybean oil, white oil, glycerin, polyethylene glycol, citric acid , Dimethyl phthalate, acetylated triethyl citrate or a mixture of more than one.
5. The method for preparing a nano-scale plant fiber modified biodegradable composite material according to claim 1, wherein the thickening agent is maleic anhydride.
6. The method for preparing nano-scale plant fiber modified biodegradable composite material according to claim 1, wherein the plant fiber is wood chips, bamboo chips, fruit husks, rice husks, wheat husks, peanut husks, and soybean husks. , At least one of bagasse, rice straw, wheat straw, sorghum stalk, cotton stalk, hemp stalk, corn cob powder, bean curd residue, etc.
7. The method for preparing a nano-scale plant fiber modified biodegradable composite material according to any one of claims 1 to 6, wherein the preset extrusion temperature is 170-220°C.
8. A nano-scale plant fiber modified biodegradable composite material, characterized in that it is prepared by the preparation method of the nano-scale plant fiber modified biodegradable composite material according to any one of claims 1 to 7.
9. A disposable tableware, characterized in that the disposable tableware is made of the nano-level plant fiber modified biodegradable composite material according to claim 8.
10. A composite material packaging bag, characterized in that the composite material packaging bag is made of the nano-level plant fiber modified biodegradable composite material according to claim 8.