A polyvinyl alcohol-areca nut shell biodegradable material and its preparation method

Abstract

The present invention provides a polyvinyl alcohol - betel nut shell biodegradable material and a preparation method thereof, comprising the following raw materials in parts by weight: 3 - 6 parts of polyvinyl alcohol, 5 - 15 parts of betel nut shell fiber powder, 8 - 20 parts of glycerol, 8 - 13 parts of water, 4 - 10 parts of starch, and further comprising 1 - 3 parts of a stabilizer. The raw materials are scientifically proportioned to prepare the biodegradable material, and they cooperate to play their roles. At the same time, the betel nut shell fiber powder is subjected to an energy beam surface modification technology, so that the prepared polyvinyl alcohol - betel nut shell biodegradable material has high mechanical properties, with a tensile rate of 151 - 172%, an elongation at break of 168 - 184%, a small change rate of elastic modulus, between 2.0 - 3.8%, a water absorption rate of 62.7 - 71.6%, and at the same time has good stability and excellent degradation performance. Its thermal stability test temperature is between 101.2 - 128.9 °C, its water resistance is 34 - 42 days, its photodegradation time is 39 - 49 days, and more than 90% of the degradation is completed within 300 days of soil burial.

Description

Technical Field

[0001] The present invention relates to the field of degradable materials, and particularly to a polyvinyl alcohol-areca nut shell biodegradable material and a preparation method thereof. Background Art

[0002] Plastic products, as essential daily necessities in people's daily lives, have extensive applications in production and life. Compared with metal materials or mineral materials, plastic products have the advantages of low cost and strong plasticity. However, with their extensive use, the problem of white pollution has attracted more and more attention. Therefore, the development of new materials with good mechanical properties and degradability has become increasingly urgent.

[0003] As an extremely safe polymer organic substance, polyvinyl alcohol is non-toxic and has no side effects on the human body, and has good biocompatibility. In particular, its aqueous gel has extensive applications in ophthalmology, wound dressings, and artificial joints in the medical field. At the same time, polyvinyl alcohol films are also used in pharmaceutical films, artificial kidney membranes, etc.

[0004] Areca nuts are native to Malaysia and are mainly distributed in tropical regions such as Yunnan and Hainan in China. They are widely cultivated in tropical regions of Asia. The world annual output of areca nuts is as high as 1.296 million tons, with a huge quantity. The by-product of areca nut processing, areca nut shells, is as high as 388,800 tons per year. Areca nut shells are of low cost, and as a production waste, their proper treatment has always been a concern, and their economic benefits remain to be further developed.

[0005] The Chinese patent literature discloses "a polyvinyl alcohol-reinforced caprolactone-starch biodegradable film and a preparation method thereof", and its application publication number is CN106065090A. This invention uses corn starch and rice starch as raw materials and mixes them with polyvinyl alcohol-reinforced caprolactone to prepare a biodegradable film material. Although this material prepares a material with a degradation effect, the raw materials used are crops such as rice and corn, with a relatively high cost. The molecular structures between the biodegradable materials made from corn and starch are tightly connected but unevenly dispersed, resulting in poor mechanical properties and a slow degradation rate.

[0006] The polyvinyl alcohol film is a green and environmentally friendly functional material with polyvinyl alcohol as the main body, added with modifiers and other auxiliaries, and processed through special processes, which can be completely degraded by microorganisms in the soil. It can be degraded into carbon dioxide and water in a short time and has the effect of improving the land. The polyvinyl alcohol film molecule has hydrophilic hydroxyl groups. Its greatest advantage is water solubility, and its greatest disadvantage is poor water resistance. As the only vinyl polymer that can be used by bacteria as a carbon source and energy source, under the action of bacteria and enzymes, 75% of polyvinyl alcohol can be degraded in 46 days, and its degradation performance is excellent. However, the tensile strength, elongation at break, and water resistance of the polyvinyl alcohol film are poor, which limits its wide application in the field of degradable composite films. It is necessary to modify polyvinyl alcohol to expand its application range. Summary of the Invention

[0007] In view of this, the present invention proposes a polyvinyl alcohol-betel nut shell biodegradable material and its preparation method to solve the above problems.

[0008] The technical solution of the present invention is realized as follows: A polyvinyl alcohol-betel nut shell biodegradable material: includes the following raw materials in parts by weight: 3-6 parts of polyvinyl alcohol, 5-15 parts of betel nut shell fiber powder, 8-20 parts of glycerol, 8-13 parts of water, and 4-10 parts of starch.

[0009] Further, a polyvinyl alcohol-betel nut shell biodegradable material includes the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of betel nut shell fiber powder, 14 parts of glycerol, 10 parts of water, and 7 parts of starch.

[0010] Further, a preparation method of a polyvinyl alcohol-betel nut shell biodegradable material includes the following steps:

[0011] S1. Prepare betel nut shell powder: After the betel nut shell is cleaned, it is dried in an oven at 80-100 °C for 10-18 h. After the betel nut shell is cut into filaments, it is ground and sieved with a pulverizer, and sieved through a 40-60 mesh sieve to obtain betel nut shell powder for standby;

[0012] S2. Prepare betel nut shell fiber powder: Mix and cook the above betel nut shell powder with sodium oxide solution. The mass-volume ratio g / mL of the betel nut shell powder and sodium oxide solution is 1:4-6. It is divided into three sections for cooking. The first section is heated to 98-105 °C in 40-60 min, the second section is heated to 145-155 °C in 80-100 min, and the third section is heated to 155-165 °C in 20-40 min. After cooling, fine pulp is obtained through screening. After the fine pulp is dried, it is crushed again to a particle size of 0.8-1.2 μm to obtain betel nut shell fiber powder, which is sealed and stored;

[0013] S3. Prepare a polyvinyl alcohol-betel nut shell blend: Weigh and take the above starch, betel nut shell fiber powder, glycerol, water, and polyvinyl alcohol and mix them evenly, and stir to obtain a polyvinyl alcohol-betel nut shell blend;

[0014] S4. Extrude the obtained polyvinyl alcohol - areca nut shell blend into sheets using a single - screw extruder, and seal and store it using a PE plastic bag.

[0015] Furthermore, the alkali amounts used for cooking are 14%, 16%, and 18% respectively.

[0016] Furthermore, a polyvinyl alcohol - areca nut shell biodegradable material further comprises 1 - 3 parts by weight of a stabilizer, preferably 2 parts by weight of the stabilizer.

[0017] Furthermore, the stabilizer is lignin, chitosan fiber, and cellulose diacetate with a mass ratio of (3 - 6):(1 - 3):(0.3 - 0.9).

[0018] Furthermore, a method for preparing a polyvinyl alcohol - areca nut shell biodegradable material comprises the following steps:

[0019] S1. Prepare areca nut shell powder: After cleaning the areca nut shells, dry them in an oven at 80 - 100 °C for 10 - 18 h. After cutting the areca nut shells into filaments, grind them with a pulverizer and sieve them through a 40 - 60 - mesh sieve to obtain areca nut shell powder for standby.

[0020] S2. Prepare areca nut shell fiber powder: Mix the above - mentioned areca nut shell powder with a sodium oxide solution for cooking. The mass - to - volume ratio of the areca nut shell powder to the sodium oxide solution is 1:4 - 6 g / mL. Divide the cooking into three stages. The alkali amounts used for cooking are 14%, 16%, and 18% respectively. In the first stage, heat up to 98 - 105 °C in 40 - 60 min, in the second stage, heat up to 145 - 155 °C in 80 - 100 min, and in the third stage, heat up to 155 - 165 °C in 20 - 40 min. After cooling, obtain fine pulp through screening. Dry the fine pulp and then crush it again to a particle size of 0.8 - 1.2 μm to obtain areca nut shell fiber powder, and seal and store it.

[0021] S3. Modify with intense pulsed electron beam: Put the above - mentioned areca nut shell fiber powder into a vacuum chamber. When the vacuum reaches 6.0 - 7.0×10 -3 Pa, turn on the magnetic field and the cathode high - voltage power supply in sequence. The cathode emits an electron beam for irradiation 1 - 3 times. The electron acceleration voltage is 15 - 30 kv, the pulse duration is 0.5 - 5 μs, the energy density is 3 - 6 J / cm 2 , the pulse interval time is 5 - 10 s, the magnetic field strength is 0.5 - 0.8 T, and the magnetic field application time is 90 - 120 s. After completion, obtain the modified areca nut shell fiber powder.

[0022] S4. Prepare a polyvinyl alcohol - areca nut shell blend: Take the above - mentioned starch, modified areca nut shell fiber powder, glycerol, water, polyvinyl alcohol, and stabilizer according to parts by weight, mix them evenly, and stir to obtain a polyvinyl alcohol - areca nut shell blend.

[0023] S5. Extrude the obtained polyvinyl alcohol - betel nut shell blend into sheets using a single - screw extruder, and seal and store it using a PE plastic bag.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention is composed of scientific proportions of raw materials such as natural organic plant fiber material betel nut shell, stabilizer, and polyvinyl alcohol. The betel nut shell fiber powder is surface - modified by an energy - carrying beam technology. Under the dual action of the stabilizer, each raw material is mixed to form degradable particles. The stabilizer selects lignin, chitosan fiber, and diacetate cellulose with a certain mass ratio, making their dispersion relatively uniform, reducing the agglomeration phenomenon, improving the internal structure of the degradable material, making its internal pore structure more stable, and having a strong binding degree between the two, enabling the molecules to be closely combined. The prepared polyvinyl alcohol - betel nut shell biodegradable material has high mechanical properties, with a tensile rate of 151 - 172%, an elongation at break of 168 - 184%, a small change rate of elastic modulus between 2.0 - 3.8%, a water absorption rate of 62.7 - 71.6%. At the same time, it has good stability and excellent degradation performance. Its thermal stability test temperature is between 101.2 - 128.9°C, water resistance is 34 - 42 days, photo - degradation time is 39 - 49 days, and more than 90% of the degradation is completed within 300 days of soil burial. Detailed implementation manners

[0026] To better understand the technical content of the present invention, specific examples are provided below to further illustrate the present invention.

[0027] The experimental methods used in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0028] The materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial channels unless otherwise specified.

[0029] Example 1

[0030] A polyvinyl alcohol - betel nut shell biodegradable material: includes the following raw materials in parts by weight: 3 parts of polyvinyl alcohol, 5 parts of betel nut shell fiber powder, 8 parts of glycerol, 8 parts of water, and 4 parts of starch.

[0031] Example 2

[0032] A polyvinyl alcohol - betel nut shell biodegradable material: includes the following raw materials in parts by weight: 6 parts of polyvinyl alcohol, 15 parts of betel nut shell fiber powder, 20 parts of glycerol, 13 parts of water, and 10 parts of starch.

[0033] Example 3

[0034] A polyvinyl alcohol - betel nut shell biodegradable material: It includes the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of betel nut shell fiber powder, 14 parts of glycerol, 10 parts of water, and 7 parts of starch;

[0035] The above Examples 1 - 3 adopt the following preparation method:

[0036] S1. Prepare betel nut shell powder: After cleaning the betel nut shell, dry it in an oven at 100 °C for 12 h. After cutting the betel nut shell into filaments, grind and sieve it with a pulverizer, and sieve it through a 50 - mesh sieve to obtain betel nut shell powder for standby;

[0037] S2. Prepare betel nut shell fiber powder: Mix the above - mentioned betel nut shell powder with sodium oxide solution for cooking. The mass - to - volume ratio of the betel nut shell powder to the sodium oxide solution is 1:5 (g / mL). Divide it into three stages for cooking, and the alkali consumption for cooking is 14%, 16%, and 18% respectively. In the first stage, heat up to 100 °C in 50 min, in the second stage, heat up to 150 °C in 90 min, and in the third stage, heat up to 160 °C in 30 min. After cooling, obtain fine pulp through screening. After drying the fine pulp, crush it again to a particle size of 1 μm to obtain betel nut shell fiber powder, and store it sealed;

[0038] S3. Prepare a polyvinyl alcohol - betel nut shell blend: Take the above - mentioned starch, betel nut shell fiber powder, glycerol, water, and polyvinyl alcohol in parts by weight, mix them evenly, and stir to obtain a polyvinyl alcohol - betel nut shell blend;

[0039] S4. Extrude the obtained polyvinyl alcohol - betel nut shell blend into sheets using a single - screw extruder, and store it sealed in a PE plastic bag.

[0040] Example 4

[0041] A polyvinyl alcohol - betel nut shell biodegradable material: It includes the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of betel nut shell fiber powder, 14 parts of glycerol, 10 parts of water, and 7 parts of starch;

[0042] The polyvinyl alcohol - betel nut shell biodegradable material adopts the following preparation method:

[0043] S1. Prepare betel nut shell powder: After cleaning the betel nut shell, dry it in an oven at 100 °C for 12 h. After cutting the betel nut shell into filaments, grind and sieve it with a pulverizer, and sieve it through a 50 - mesh sieve to obtain betel nut shell powder for standby;

[0044] S2. Preparation of areca nut shell fiber powder: Mix the above-mentioned areca nut shell powder with sodium oxide solution for cooking. The mass-volume ratio of the areca nut shell powder to the sodium oxide solution is 1:5 g / mL, and it is divided into three stages of cooking. The alkali consumption for cooking is 14%, 16%, and 18% respectively. In the first stage, it is heated to 100 °C in 50 min, in the second stage, it is heated to 150 °C in 90 min, and in the third stage, it is heated to 160 °C in 30 min. After cooling, fine pulp is obtained through screening. The fine pulp is dried and then crushed again to a particle size of 1 μm to obtain areca nut shell fiber powder, which is sealed and stored;

[0045] S3. Modification by high-intensity pulsed electron beam: Put the above-mentioned areca nut shell fiber powder into a vacuum chamber. When the vacuum reaches 6.5×10 -3 Pa, turn on the magnetic field and the cathode high-voltage power supply in sequence. The cathode emits electron beams for irradiation 2 times. The electron acceleration voltage is 22 kV, the pulse duration is 0.25 μs, the energy density is 4 J / cm 2 , the pulse interval time is 8 s, the magnetic field intensity is 0.7 T, and the magnetic field application time is 100 s. After that, the modified areca nut shell fiber powder is obtained;

[0046] S4. Preparation of polyvinyl alcohol-areca nut shell blend: Take the above-mentioned starch, modified areca nut shell fiber powder, glycerol, water, and polyvinyl alcohol in parts by weight, mix them evenly, and stir to obtain a polyvinyl alcohol-areca nut shell blend;

[0047] S5. Extrude the above-obtained polyvinyl alcohol-areca nut shell blend into sheets using a single-screw extruder, and seal and store it using a PE plastic bag.

[0048] Example 5

[0049] A polyvinyl alcohol-areca nut shell biodegradable material, comprising the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of areca nut shell fiber powder, 14 parts of glycerol, 10 parts of water, 7 parts of starch, and 2 parts of stabilizer. The stabilizer is lignin, chitosan fiber, and diacetate cellulose with a mass ratio of 4:2:0.7;

[0050] The preparation method of the polyvinyl alcohol-areca nut shell biodegradable material is as follows:

[0051] S1. Preparation of areca nut shell powder: After the areca nut shell is cleaned, it is dried in an oven at 100 °C for 12 h. After the areca nut shell is cut into filaments, it is ground and sieved with a pulverizer, and passed through a 50-mesh sieve to obtain areca nut shell powder, which is reserved;

[0052] S2. Preparation of areca nut shell fiber powder: Mix the above-mentioned areca nut shell powder with sodium oxide solution and cook them. The mass-volume ratio of the areca nut shell powder to the sodium oxide solution is 1:5 (g / mL). The cooking is divided into three stages, and the alkali consumption for cooking is 14%, 16%, and 18% respectively. In the first stage, heat up to 100 °C in 50 minutes, in the second stage, heat up to 150 °C in 90 minutes, and in the third stage, heat up to 160 °C in 30 minutes. After cooling, obtain fine pulp through screening. Dry the fine pulp and then crush it again to a particle size of 1 μm to obtain areca nut shell fiber powder, and store it sealed;

[0053] S3. Preparation of polyvinyl alcohol-areca nut shell blend: Take the above-mentioned starch, areca nut shell fiber powder, glycerol, water, polyvinyl alcohol, and stabilizer according to parts by weight, mix them evenly, and stir to obtain a polyvinyl alcohol-areca nut shell blend;

[0054] S4. Extrude the obtained polyvinyl alcohol-areca nut shell blend into sheets using a single-screw extruder, and store it sealed in a PE plastic bag.

[0055] Example 6

[0056] A polyvinyl alcohol-areca nut shell biodegradable material, comprising the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of areca nut shell fiber powder, 14 parts of glycerol, 10 parts of water, 7 parts of starch, and 2 parts of stabilizer. The stabilizer is lignin, chitosan fiber, and diacetate cellulose with a mass ratio of 4:2:0.7;

[0057] The polyvinyl alcohol-areca nut shell biodegradable material is prepared by the following method:

[0058] S1. Preparation of areca nut shell powder: After cleaning the areca nut shell, dry it in an oven at 100 °C for 12 hours. Cut the areca nut shell into filaments, then grind and sieve it with a pulverizer. After passing through a 50-mesh sieve, obtain areca nut shell powder for standby;

[0059] S2. Preparation of areca nut shell fiber powder: Mix the above-mentioned areca nut shell powder with sodium oxide solution and cook them. The mass-volume ratio of the areca nut shell powder to the sodium oxide solution is 1:5 (g / mL). The cooking is divided into three stages, and the alkali consumption for cooking is 14%, 16%, and 18% respectively. In the first stage, heat up to 100 °C in 50 minutes, in the second stage, heat up to 150 °C in 90 minutes, and in the third stage, heat up to 160 °C in 30 minutes. After cooling, obtain fine pulp through screening. Dry the fine pulp and then crush it again to a particle size of 1 μm to obtain areca nut shell fiber powder, and store it sealed;

[0060] S3. Intense pulsed electron beam modification: Put the above-mentioned areca nut shell fiber powder into a vacuum chamber. When the vacuum reaches 6.5×10 -3 Pa, turn on the magnetic field and the cathode high-voltage power supply in sequence. The cathode emits electron beams for irradiation 2 times. The electron acceleration voltage is 22 kV, the pulse duration is 0.25 μs, and the energy density is 4 J / cm2 , with a pulse interval of 8 s, a magnetic field strength of 0.7 T, and a magnetic field application time of 100 s. After that, the modified areca nut shell fiber powder is obtained;

[0061] S4. Prepare the polyvinyl alcohol-areca nut shell blend: Take the above-mentioned starch, modified areca nut shell fiber powder, glycerol, water, polyvinyl alcohol, and stabilizer by weight, mix them evenly, and stir to obtain the polyvinyl alcohol-areca nut shell blend;

[0062] S5. Extrude the obtained polyvinyl alcohol-areca nut shell blend into sheets using a single-screw extruder, and seal and store them using PE plastic bags.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 6 is that a polyvinyl alcohol-areca nut shell biodegradable material includes the following raw materials by weight: 7 parts of polyvinyl alcohol, 2 parts of areca nut shell fiber powder, 5 parts of glycerol, 3 parts of water, 2 parts of starch, and 5 parts of stabilizer.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 6 is that a polyvinyl alcohol-areca nut shell biodegradable material, and the stabilizer is lignin, chitosan fiber, and diacetate cellulose with a mass ratio of 1:1:1.

[0067] I. Mechanical property test

[0068] Prepare films with a thickness of 3 mm from the polyvinyl alcohol-areca nut shell biodegradable materials prepared in Examples 1-5 above, ordinary corn starch biodegradable materials, and pure polyvinyl alcohol film materials, and test their elongation at break, percentage elongation at break, and elastic modulus change rate according to the standard of 《GB / T1040.2-2006》; Place the films in a laboratory simulation environment for 30 days, with environmental conditions of light intensity 1×10 5 Lux, temperature 52±3℃, humidity 80%, and measure the change rate of the elastic modulus; Place the obtained films in an environment with 90% humidity for 24 h, take them out, and the mass change rate before and after testing is the water absorption rate; The test results are as follows:

[0069]

[0070]

[0071] As can be seen from the results in the above table, compared with the comparative example group and the corn starch degradation material, the film prepared by the example group of the present invention has a higher tensile rate and elongation at break. Comparing Examples 1-3 and Example 5 can show that after adding the stabilizer, the areca nut shell fiber powder molecules and polyvinyl alcohol are more evenly dispersed without agglomeration, and there is a strong binding degree between the two, and the molecules can be closely combined, improving the stability of the system and increasing the strength of the degradation material; the change rate of the elastic modulus of the example group is within 5%, which is the change range of the elastic modulus. Due to the conditions of light and high temperature, the elastic modulus of the film in the comparative example group has increased to varying degrees, indicating certain signs of aging.

[0072] Among them, the effect of Example 6 is better, which can illustrate that under the condition of reasonable ratio, the physical properties of the areca nut shell fiber powder are effectively enhanced by the combined action of adding the stabilizer and physically modifying the areca nut shell fiber powder. During the irradiation process, the short-pulse high-energy-density electron beam is deposited on the surface of the fiber powder, causing a rapid temperature rise on the powder surface and generating a thermal stress effect. The fiber powder molecules expand, enabling the electron beam energy to be distributed among the powder molecules. While expanding the molecular layer spacing, the tensile stress between the powder molecules is enhanced. After the molecular layer spacing expands, it is conducive to the binding with polyvinyl alcohol, stabilizer, etc., so that the mechanical properties are increased, the deterioration of the tensile strength is inhibited, the change of the elastic modulus is small, and the water absorption rate is high.

[0073] II. Stability and degradation rate

[0074] Thermal stability: Use a synchronous thermal analyzer to analyze the heat resistance of the above-mentioned degradable material film, with a heating rate of 10 °C / min and a temperature range of 30-200 °C, and record the starting decomposition temperature;

[0075] Water resistance: Cut the degradable material film into 2×2 cm, soak it in water at 50±5 °C, and record the number of days when the film shows obvious dissolution;

[0076] Photodegradation: Cut the degradable material film into 1.5×1.5 cm, place it under a simulated lamp, with a light intensity of 30000 lux, a temperature of 32±3 °C, and a humidity of 70±5%, and test the time when obvious degradation occurs;

[0077] Soil burial degradation: Cut the degradable material film into 1.5×1.5 cm, bury it in the test soil, make a mark, and test the time when more than 90% of it degrades.

[0078]

[0079] From the above results, it can be seen that the degradable material of the present invention has good thermal stability and water resistance. At the same time, the photo-degradation time is 39 - 49 days, and more than 90% of the degradation is completed within 300 days of soil burial. Among the above characteristics, the effect of Example 6 is the best. Comparing Example 6 with Comparative Examples 1 and 2 shows that the ratio between the agents and stabilizers in specific ratios of each raw material can synergistically play their roles better; comparing Example 6 and Example 3, with the combination of adding stabilizers and physically modifying the areca nut shell fiber powder, the molecular layer spacing is expanded, effectively improving its degradation ability. Adding stabilizers can also enhance the bonding effect of the fiber particle molecules, and the decomposed film is a three-dimensional network structure; comparing Example 6 and Example 4, after adding stabilizers, the molecules of the areca nut shell fiber powder and polyvinyl alcohol are more evenly dispersed without agglomeration, thus achieving synchronous degradation, and the surface of the film degrades more completely.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polyvinyl alcohol - areca nut shell biodegradable material, characterized in that: It comprises the following raw materials in parts by weight: 3 - 6 parts of polyvinyl alcohol, 5 - 15 parts of betel nut shell fiber powder, 8 - 20 parts of glycerol, 8 - 13 parts of water, 4 - 10 parts of starch, and 1 - 3 parts of stabilizer. The stabilizer is lignin, chitosan fiber, and diacetate cellulose with a mass ratio of (3 - 6):(1 - 3):(0.3 - 0.9). The preparation method of the polyvinyl alcohol - betel nut shell biodegradable material comprises the following steps: S1. Prepare betel nut shell powder: After cleaning the betel nut shell, dry it in an oven at 80 - 100 °C for 10 - 18 h. Cut the betel nut shell into filaments, then grind and sieve it with a pulverizer, and sieve it through a 40 - 60 - mesh sieve to obtain betel nut shell powder for standby. S2. Prepare betel nut shell fiber powder: Mix the above - mentioned betel nut shell powder with sodium oxide solution for cooking. The mass - to - volume ratio g / mL of the betel nut shell powder and sodium oxide solution is 1:4 - 6. Divide it into three - stage cooking, and the alkali consumption for cooking is 14%, 16%, and 18% respectively. In the first stage, heat it up to 98 - 105 °C in 40 - 60 min, in the second stage, heat it up to 145 - 155 °C in 80 - 100 min, and in the third stage, heat it up to 155 - 165 °C in 20 - 40 min. After cooling, obtain fine pulp through screening. Dry the fine pulp and then crush it again to a particle size of 0.8 - 1.2 μm to obtain betel nut shell fiber powder, and store it sealed. S3. Modification by high-current pulsed electron beam: Put the above-mentioned areca husk fiber powder into a vacuum chamber. When the vacuum reaches 6.0 - 7.0×10 -3 Pa, turn on the magnetic field and the cathode high-voltage power supply in sequence. The cathode emits an electron beam for irradiation 1 - 3 times, with a pulse interval of 5 - 10 s, an electron acceleration voltage of 15 - 30 kV, a pulse duration of 0.5 - 5 μs, and an energy density of 3 - 6 J / cm 2 . The magnetic field strength is 0.5 - 0.8 T, and the magnetic field application time is 90 - 120 s. After that, the modified areca husk fiber powder is obtained; S4. Prepare a polyvinyl alcohol - betel nut shell blend: Take the above - mentioned starch, modified betel nut shell fiber powder, glycerol, water, polyvinyl alcohol, and stabilizer in parts by weight, mix them evenly, and stir to obtain a polyvinyl alcohol - betel nut shell blend. S5. Extrude the obtained polyvinyl alcohol - betel nut shell blend into sheets using a single - screw extruder, and store it sealed with a PE plastic bag.

2. The polyvinyl alcohol-areca nut shell biodegradable material according to claim 1, characterized in that: It comprises the following raw materials in parts by weight: 4 parts of polyvinyl alcohol, 10 parts of betel nut shell fiber powder, 14 parts of glycerol, 10 parts of water, and 7 parts of starch.

3. A polyvinyl alcohol-areca nut shell biodegradable material according to claim 1, characterized in that: It also comprises 2 parts by weight of stabilizer.

Images