A biodegradable bamboo fiber PBAT material and film preparation method

Abstract

The present invention relates to the technical field of degradable materials, and specifically to a degradable bamboo fiber PBAT material and a film preparation method. The degradable bamboo fiber PBAT material provided by the present invention is prepared from bamboo fiber, PBAT, a chain extender, a nucleating agent, a plasticizer, an inorganic filler, a coupling agent, a lubricant, and polyethylene grafted maleic anhydride. The degradable bamboo fiber PBAT material provided by the present invention is fully combined with bamboo fiber, PBAT, polyethylene grafted maleic anhydride, a chain extender, a nucleating agent and a plasticizer to effectively enhance the mechanical properties of the bamboo fiber PBAT material and improve the tensile strength and stiffness; at the same time, the type and amount of the plasticizer are accurately controlled, which not only does not affect the mechanical properties of the polymer, but also can give the degradable bamboo fiber PBAT material good plasticity and processability.

Description

Technical field:

[0001] The present invention relates to the technical field of degradable materials, and in particular to a degradable bamboo fiber PBAT material and a film preparation method. Background technology:

[0002] Bamboo cellulose is a common natural polymer material. The development of this most abundant renewable resource in nature, especially its modification research, has attracted more and more attention in recent years. Generally, the modification methods of bamboo fiber include: surface modification, graft copolymerization and blending modification. Among them, surface modification and graft copolymerization have better effects, but they have strict requirements on process conditions and are difficult to industrialize on a large scale. The blending modification process is simple and easy to achieve industrial production, especially blending with some degradable polymers such as polylactic acid (PLA), polybutylene terephthalate-adipate (PBAT), polycaprolactone (PCL), etc., can obtain completely renewable and degradable polymer materials, which is of great significance for reducing environmental pollution.

[0003] In addition to good biological properties, degradable polymers also require good flexibility of the molecular chain and good chemical stability. Bamboo fiber has good moisture resistance, but it is not resistant to high temperatures, has low strength, and low toughness. PBAT has the characteristics of both polybutyl acrylate (PBA) and polybutylene terephthalate (PBT). It has good ductility and elongation at break, good heat resistance and impact resistance, and excellent biodegradability. It is one of the most popular and best degradable materials in the research of biodegradable plastics. It is particularly important to improve the hydrophilicity, stability and processing properties of cellulose through blending modification.

[0004] The Chinese patent application document with publication number CN111548611A discloses a high-density bamboo powder / PBAT / polylactic acid biodegradable plastic and its preparation method, which includes bamboo powder, succinic acid, PBAT, polylactic acid, inorganic powder additives, stabilizers, etc. The groups on the cellulose, PLA and PBAT macromolecular chains are activated under the catalytic action of biological enzymes, and then cross-linked in a high-temperature molten state, making full use of the good softness and ductility of the PBAT molecular chain segments to improve the toughness and impact resistance of the composite material. However, the mechanical properties of the biodegradable plastics prepared by this method are poor, which is not conducive to improving the processing performance.

[0005] In summary, the existing technology generally has technical problems such as bamboo fiber is not resistant to high temperature and has low strength, poor mechanical properties after blending with PBAT, and unstable processing performance. Summary of the invention:

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a degradable bamboo fiber PBAT material and a film preparation method.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A degradable bamboo fiber PBAT material comprises the following components and their weight proportions:

[0009] 20-40 parts of bamboo fiber, 40-70 parts of PBAT, 5-10 parts of chain extender, 1-3 parts of nucleating agent, 5-8 parts of plasticizer, 10-15 parts of inorganic filler, 1-3 parts of coupling agent, 2-5 parts of lubricant, and 3-5 parts of polyethylene grafted maleic anhydride.

[0010] The degradable bamboo fiber PBAT material provided by the present invention is fully combined with bamboo fiber, PBAT, polyethylene grafted maleic anhydride, chain extender, nucleating agent and plasticizer to effectively enhance the mechanical properties of the material, improve the tensile strength and stiffness of the material, and at the same time improve the high temperature resistance of the material, reduce the thermal decomposition and oxidative degradation of the material, and give the material good plasticity and processability. Among them, polyethylene grafted maleic anhydride can improve the compatibility of bamboo fiber with other components; PBAT has good ductility and elongation at break, and has good heat resistance and impact resistance.

[0011] Furthermore, the particle size of the bamboo fiber in the degradable bamboo fiber PBAT material is 400-1000 mesh; the number average molecular weight of the PBAT is greater than 100, and the melt index is 3-10 / 10min.

[0012] Furthermore, the chain extender in the degradable bamboo fiber PBAT material is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 31-35:7-11.

[0013] In the production process of polymer materials, due to thermal degradation and hydrolysis, the molecular weight is reduced, the number of terminal carboxyl groups increases, and the mechanical properties of the polymer are reduced. The addition of a chain extender can react with the polymer to recouple the degraded molecular chain, increase the weight average molecular weight of the polymer, and thus improve the mechanical properties of the polymer material. The glycidyl methacrylate selected in the present invention has an acrylate double bond and an epoxy group, has a high reactivity, and 2-imidazole ketone has an imino active hydrogen, which can be copolymerized with a terminal hydroxyl group. The inventor found in the research process that although glycidyl methacrylate can improve the mechanical properties of the material, the degradation performance of the material decreases, and the addition of 2-imidazole ketone can effectively avoid this phenomenon. Therefore, the present invention uses glycidyl methacrylate and 2-imidazole ketone to form a chain extender and add it to the degradable bamboo fiber PBAT material formula, so that the prepared material has good biodegradability and mechanical properties. At the same time, glycidyl methacrylate and 2-imidazole ketone can effectively improve the hydrolysis resistance of PBAT, effectively solve the problem of unstable film bubbles in the bamboo fiber PBAT material during film blowing, and improve the performance of the film.

[0014] Furthermore, the nucleating agent in the degradable bamboo fiber PBAT material is sebacic acid diphenyl dihydrazide.

[0015] The present invention adopts sebacic acid diphenyl dihydrazide as a nucleating agent, which can be dissolved into the PBAT melt at the processing temperature, first crystallizes during the cooling process of the resin melt, and forms nano-sized fibrous crystals through intermolecular self-assembly, inducing PBAT molecules to crystallize, thereby shortening the molding cycle of the degradable bamboo fiber PBAT material, improving its heat resistance and bending modulus, and achieving the purpose of surface gloss.

[0016] Furthermore, the plasticizer in the degradable bamboo fiber PBAT material is composed of dibutyl phthalate, dibutyl sebacate, and dioctyl epoxidized tetrahydrophthalate in a mass ratio of 9-13:2-6:25-29.

[0017] The addition of plasticizers can reduce the glass transition temperature (Tg) of polymers, making them have good processing properties, but the addition of plasticizers can also reduce the strength of polymers, thereby affecting their mechanical properties, so that the obtained polymers cannot be made into films by film blowing machines. Therefore, in the research and development and production of polymer materials, it is necessary to accurately control and adjust the type and amount of plasticizers. In the present invention, dibutyl phthalate, dibutyl sebacate, and epoxidized tetrahydrophthalic acid dioctyl ester are used as plasticizers, and their dosage ratio is accurately controlled, which can not only improve the processing properties of the polymer, but also will not affect the mechanical properties of the polymer.

[0018] Furthermore, the inorganic filler in the degradable bamboo fiber PBAT material is composed of silicon dioxide and mica powder in a mass ratio of 2-5:7-11.

[0019] In the present invention, adding inorganic fillers to the formula of the degradable bamboo fiber PBAT material can not only improve the heat resistance of the material, but also improve the mechanical properties of the material to a certain extent and improve its processability. The inventor found in the research process that when the inorganic filler is composed of silica and mica powder in a certain mass ratio to form an inorganic filler component, the mechanical properties and high temperature resistance of the degradable bamboo fiber PBAT material are the best.

[0020] Furthermore, the particle size of the inorganic filler is 200-400 nm.

[0021] Furthermore, the coupling agent in the degradable bamboo fiber PBAT material is one of vinyl trimethoxy silane, γ-aminopropyl triethoxy silane, and vinyl triethoxy silane.

[0022] Silane coupling agents have both reactive groups that can combine with inorganic materials and reactive groups that can combine with organic materials. The present invention uses silane coupling agents to perform surface treatment on bamboo fiber raw materials and inorganic fillers, forming a very thin silicon-oxygen bond connection film on the surface of the bamboo fiber and the inorganic filler, increasing the adhesion and compatibility with PBAT, and then mixing with the organic raw materials, effectively improving the bonding strength between the inorganic raw materials and the organic raw materials, playing a bridging role, and making the prepared degradable bamboo fiber PBAT material have better processing performance and mechanical properties.

[0023] Furthermore, the lubricant in the degradable bamboo fiber PBAT material is composed of α-hydroxy fatty acid and calcium stearate in a mass ratio of 19-22:11-15.

[0024] In the present invention, α-hydroxy fatty acid and calcium stearate are used to form a lubricant. When the polymer is deformed, the lubricant can be inserted between the polymer molecular chains to make the polymer molecular chains slide and rotate relative to each other, thereby reducing the friction between polymer molecules and improving the compatibility between polymer molecules, which is beneficial to improving the mechanical properties of bamboo fiber PBAT materials.

[0025] A method for preparing a film using the above-mentioned degradable bamboo fiber PBAT material comprises the following steps:

[0026] S1. Dry the bamboo fiber at 80-150°C for 15-30 minutes, add it to a hot mixer together with the inorganic filler, add the atomized coupling agent at 50-100rpm and 90-110°C, and mix well;

[0027] S2. Continue to add lubricant, chain extender, nucleating agent, polyethylene grafted maleic anhydride into the hot mixer, heat to 110-120 ° C and melt;

[0028] S3. Continue to add PBAT and plasticizer to the hot mixer, heat to 135°C, stir at a speed of 150-200rpm for 20-35min, mix well, and cool to 40-50°C at a speed of 50-100rpm to obtain a premix;

[0029] S4. The premix obtained in step S3 is put into a twin-screw extruder for extrusion, cooling, and pelletizing to obtain a masterbatch;

[0030] S5. The masterbatch obtained in step S4 is blown into a film by a film blowing machine to obtain a degradable bamboo fiber PBAT film.

[0031] Furthermore, in step S4, the extrusion temperature of the twin-screw extruder is 145-165°C, and the screw speed is 50-100rpm; in step S5, the screw temperature of the film blowing machine is 140-165°C, the die head temperature is 170-180°C, and the film thickness is 7-10μm.

[0032] Compared with the prior art, the biodegradable bamboo fiber PBAT material and film preparation method provided by the present invention have the following technical advantages:

[0033] (1) The degradable bamboo fiber PBAT material provided by the present invention is a combination of bamboo fiber, PBAT, polyethylene grafted maleic anhydride, chain extender, nucleating agent and plasticizer, which effectively enhances the mechanical properties of the material and improves the tensile strength and stiffness of the material;

[0034] (2) The biodegradable bamboo fiber PBAT material provided by the present invention accurately controls the type and amount of plasticizer, which not only does not affect the mechanical properties of the polymer, but also gives the biodegradable bamboo fiber PBAT material good plasticity and processability;

[0035] (3) The degradable bamboo fiber PBAT material provided by the present invention has good biodegradability. Specific implementation method:

[0036] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Those skilled in the art can make various modifications based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0037] The raw material components involved in this specific embodiment are all commonly used industrial raw materials, and those skilled in the art can purchase them through regular channels.

[0038] Example 1: A biodegradable bamboo fiber PBAT material and film preparation method

[0039] The degradable bamboo fiber PBAT material comprises the following components and their weight proportions:

[0040] 20 parts of bamboo fiber, 70 parts of PBAT, 5 parts of chain extender, 3 parts of diphenyl dihydrazide sebacic acid, 5 parts of plasticizer, 15 parts of inorganic filler, 1 part of vinyl trimethoxy silane, 5 parts of lubricant, and 3 parts of polyethylene grafted maleic anhydride.

[0041] The particle size of the bamboo fiber in the degradable bamboo fiber PBAT material is 400 mesh; the number average molecular weight of the PBAT is greater than 100, and the melt index is 3 / 10min.

[0042] The chain extender is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 31:7. The plasticizer is composed of dibutyl phthalate, dibutyl sebacate, and epoxidized tetrahydrophthalate in a mass ratio of 9:2:25. The inorganic filler is composed of silicon dioxide and mica powder in a mass ratio of 2:7; the particle size of the inorganic filler is 200nm. The lubricant is composed of α-hydroxy fatty acid and calcium stearate in a mass ratio of 19:11.

[0043] The method for preparing a film using the above-mentioned degradable bamboo fiber PBAT material comprises the following steps:

[0044] S1. The bamboo fiber was dried at 80°C for 30 minutes, added to a hot mixer together with an inorganic filler, and atomized vinyl trimethoxysilane was added at 50 rpm and 110°C and mixed evenly;

[0045] S2. Continue to add lubricant, chain extender, sebacic acid diphenyl dihydrazide, polyethylene grafted maleic anhydride into the hot mixer, heat to 110 ° C and melt;

[0046] S3. Continue to add PBAT and plasticizer to the hot mixer, raise the temperature to 135°C, stir at a speed of 150 rpm for 35 minutes, mix well, and cool to 40°C at a speed of 50 rpm to obtain a premix;

[0047] S4. The premix obtained in step S3 was extruded into a twin-screw extruder, cooled and pelletized at an extrusion temperature of 145 ° C and a screw speed of 50 rpm to obtain a masterbatch;

[0048] S5. The masterbatch obtained in step S4 is blown into a film by a film blowing machine, the screw temperature is 140° C., the die temperature is 170° C., and the film thickness is 7 μm, to obtain a degradable bamboo fiber PBAT film.

[0049] Example 2: A biodegradable bamboo fiber PBAT material and film preparation method

[0050] The degradable bamboo fiber PBAT material comprises the following components and their weight proportions:

[0051] 40 parts of bamboo fiber, 40 parts of PBAT, 10 parts of chain extender, 1 part of diphenyl dihydrazide sebacic acid, 8 parts of plasticizer, 10 parts of inorganic filler, 3 parts of γ-aminopropyl triethoxysilane, 2 parts of lubricant, and 5 parts of polyethylene grafted maleic anhydride.

[0052] The particle size of the bamboo fiber in the degradable bamboo fiber PBAT material is 1000 mesh; the number average molecular weight of the PBAT is greater than 100, and the melt index is 10 / 10min.

[0053] The chain extender is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 35:11. The plasticizer is composed of dibutyl phthalate, dibutyl sebacate, and epoxidized tetrahydrophthalate in a mass ratio of 13:6:29. The inorganic filler is composed of silicon dioxide and mica powder in a mass ratio of 5:11; the particle size of the inorganic filler is 400nm. The lubricant is composed of α-hydroxy fatty acid and calcium stearate in a mass ratio of 22:15.

[0054] The method for preparing a film using the above-mentioned degradable bamboo fiber PBAT material comprises the following steps:

[0055] S1. The bamboo fiber was dried at 150°C for 15 minutes, added to a hot mixer together with an inorganic filler, and atomized γ-aminopropyl triethoxysilane was added at 100 rpm and 90°C, and mixed evenly;

[0056] S2. Continue to add lubricant, chain extender, sebacic acid diphenyl dihydrazide, polyethylene grafted maleic anhydride into the hot mixer, heat to 120 ° C and melt;

[0057] S3. Continue to add PBAT and plasticizer to the hot mixer, heat to 135°C, stir at a speed of 200 rpm for 20 min, mix well, and cool to 50°C at a speed of 100 rpm to obtain a premix;

[0058] S4. The premix obtained in step S3 was put into a twin-screw extruder for extrusion, cooling and pelletizing. The extrusion temperature was 165 ° C and the screw speed was 100 rpm to obtain a masterbatch.

[0059] S5. The masterbatch obtained in step S4 is blown into a film by a film blowing machine, the screw temperature is 165° C., the die temperature is 180° C., and the film thickness is 10 μm, to obtain a degradable bamboo fiber PBAT film.

[0060] Example 3: A biodegradable bamboo fiber PBAT material and film preparation method

[0061] The degradable bamboo fiber PBAT material comprises the following components and their weight proportions:

[0062] 35 parts of bamboo fiber, 56 parts of PBAT, 8 parts of chain extender, 2 parts of diphenyl dihydrazide sebacic acid, 7 parts of plasticizer, 13 parts of inorganic filler, 2 parts of vinyl triethoxy silane, 4 parts of lubricant, and 4 parts of polyethylene grafted maleic anhydride.

[0063] The particle size of the bamboo fiber in the degradable bamboo fiber PBAT material is 800 mesh; the number average molecular weight of the PBAT is greater than 100, and the melt index is 7 / 10min.

[0064] The chain extender is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 33:10. The plasticizer is composed of dibutyl phthalate, dibutyl sebacate, and epoxidized tetrahydrophthalate in a mass ratio of 10:4:27. The inorganic filler is composed of silicon dioxide and mica powder in a mass ratio of 4:9; the particle size of the inorganic filler is 300nm. The lubricant is composed of α-hydroxy fatty acid and calcium stearate in a mass ratio of 21:14.

[0065] A method for preparing a film using the above-mentioned degradable bamboo fiber PBAT material comprises the following steps:

[0066] S1. The bamboo fiber was dried at 120°C for 21 minutes, added to a hot mixer together with an inorganic filler, and atomized vinyl triethoxysilane was added at 80 rpm and 100°C and mixed evenly;

[0067] S2. Continue to add lubricant, chain extender, sebacic acid diphenyl dihydrazide, polyethylene grafted maleic anhydride into the hot mixer, heat to 115 ° C and melt;

[0068] S3. Continue to add PBAT and plasticizer to the hot mixer, heat to 135°C, stir at a speed of 180 rpm for 29 minutes, mix well, and cool to 45°C at a speed of 80 rpm to obtain a premix;

[0069] S4. The premix obtained in step S3 was extruded into a twin-screw extruder, cooled and pelletized at an extrusion temperature of 152°C and a screw speed of 80 rpm to obtain a masterbatch;

[0070] S5. The masterbatch obtained in step S4 is blown into a film by a film blowing machine, the screw temperature is 155° C., the die temperature is 175° C., and the film thickness is 9 μm, to obtain a degradable bamboo fiber PBAT film.

[0071] Example 4: A biodegradable bamboo fiber PBAT material and film preparation method

[0072] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this example and Example 3 is that the chain extender in this example is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 34:9.

[0073] In this embodiment, the preparation method of the degradable bamboo fiber PBAT material film is the same as that in Example 3.

[0074] Example 5: A biodegradable bamboo fiber PBAT material and film preparation method

[0075] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this example and Example 3 is that the plasticizer in this example is composed of dibutyl phthalate, dibutyl sebacate, and dioctyl epoxidized tetrahydrophthalate in a mass ratio of 11:5:28.

[0076] In this embodiment, the preparation method of the degradable bamboo fiber PBAT material film is the same as that in Example 3.

[0077] Example 6: A biodegradable bamboo fiber PBAT material and film preparation method

[0078] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this example and Example 3 is that the inorganic filler in this example is composed of silicon dioxide and mica powder in a mass ratio of 3:8.

[0079] In this embodiment, the preparation method of the degradable bamboo fiber PBAT material film is the same as that in Example 3.

[0080] Comparative Example 1

[0081] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 4. The difference between this comparative example and Example 4 is that the chain extender in this comparative example is glycidyl methacrylate.

[0082] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 4.

[0083] Comparative Example 2

[0084] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 4. The difference between this comparative example and Example 4 is that the chain extender in this comparative example is composed of glycidyl methacrylate and 2-imidazole ketone in a mass ratio of 2:11.

[0085] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 4.

[0086] Comparative Example 3

[0087] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this comparative example and Example 3 is that the nucleating agent sodium benzoate is used instead of diphenyl dihydrazide sebacic acid in this comparative example.

[0088] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 3.

[0089] Comparative Example 4

[0090] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 5. The difference between this comparative example and Example 5 is that acetyl tributyl citrate is used as a plasticizer in this comparative example.

[0091] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 5.

[0092] Comparative Example 5

[0093] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 5. The difference between this comparative example and Example 5 is that the plasticizer in this comparative example is composed of dibutyl phthalate, dibutyl sebacate, and dioctyl epoxidized tetrahydrophthalate in a mass ratio of 6:15:4.

[0094] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 5.

[0095] Comparative Example 6

[0096] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 6. The difference between this comparative example and Example 6 is that the inorganic filler in this comparative example is talcum powder.

[0097] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 6.

[0098] Comparative Example 7

[0099] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 6. The difference between this comparative example and Example 6 is that the inorganic filler in this comparative example is composed of silicon dioxide and mica powder in a mass ratio of 9:2.

[0100] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 6.

[0101] Comparative Example 8

[0102] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this comparative example and Example 3 is that isobutyl triethoxy silane is used instead of vinyl triethoxy silane in this comparative example.

[0103] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 3.

[0104] Comparative Example 9

[0105] The composition of the degradable bamboo fiber PBAT material is similar to that of Example 3. The difference between this comparative example and Example 3 is that the lubricant in this comparative example is polyethylene wax.

[0106] The preparation method of the degradable bamboo fiber PBAT material film described in this comparative example is the same as that in Example 3.

[0107] Test Example 1: Degradation Performance Test

[0108] Test sample: bamboo fiber PBAT material film prepared in Example 4 and Comparative Example 1-2;

[0109] Test method: The test samples were subjected to biodegradation test using the method of ASTM D5511-18.

[0110] Test results: The test results are shown in Table 1.

[0111] Table 1 Degradation performance test results

[0112]

[0113] As can be seen from Table 1, the biodegradability of the degradable bamboo fiber PBAT material film prepared in Example 4 of the present invention is 12.5% ​​in 30 days. The biodegradability in 90 days is 83.6%, which has good biodegradability. Compared with Example 4, the chain extender in Comparative Example 1 is glycidyl methacrylate, but the biodegradation rate of the prepared film is greatly reduced, which shows that the addition of glycidyl methacrylate will affect the biodegradability of the material, while 2-imidazole can effectively avoid the effect of glycidyl methacrylate on the biodegradability; Comparative Example 2 changes the dosage ratio of glycidyl methacrylate and 2-imidazole, but the biodegradability of the prepared film is slightly reduced, which shows that the dosage ratio of glycidyl methacrylate and 2-imidazole in the present invention has been optimized.

[0114] Test Example 2: Mechanical Properties Test

[0115] Test sample: bamboo fiber PBAT material film prepared in Examples 3-6 and Comparative Examples 1-9; the test sample has a width of 15 mm and a thickness of 9 μm.

[0116] Test method: According to GB / T1040.3-2006 "Determination of tensile properties of plastics", the tensile strength, breaking strength, Young's elastic modulus, breaking elongation, specified non-proportional extension strength Rp0.2 and tear strength of the test samples are tested.

[0117] Test results: The test results are shown in Table 2.

[0118] Table 2 Mechanical properties test results

[0119]

[0120] It can be seen from Table 2 that the degradable bamboo fiber PBAT material film provided by the present invention has good mechanical properties, with a maximum breaking force of 2.82 lbs, a maximum force of 3.37 lbs, a tensile strength of 10.75 MPa, a breaking strength of 10.68 MPa, a Young's elastic modulus of 43.51 MPa, an elongation at break of 710.6%, a specified non-proportional extension strength of 5.12 MPa, and a tear strength of 5793 mN.

[0121] Compared with Example 3, Comparative Example 3 uses sodium benzoate instead of sebacic acid diphenyl dihydrazide as a nucleating agent, but the mechanical properties of the obtained film are reduced, which shows that the sebacic acid diphenyl dihydrazide used in the present invention can effectively improve the mechanical properties of the material, and not all nucleating agents can achieve the effect of the nucleating agent of the present invention on improving the mechanical properties; the coupling agent in Comparative Example 8 uses isobutyl triethoxy silane, but the mechanical properties of the obtained film are significantly reduced, which shows that the silane coupling agent used in the present invention can organically combine bamboo fiber and inorganic filler with PBAT, greatly improving the mechanical properties of the material, and not all silane coupling agents can achieve the technical effects of the present invention; the lubricant in Comparative Example 9 uses polyethylene wax, and the mechanical properties of the obtained film material are slightly reduced, which shows that the lubricant used in the present invention is beneficial to improving the mechanical properties of the material.

[0122] Compared with Example 4, Comparative Examples 1 and 2 changed the components and dosage ratio of the chain extender, but the mechanical properties of the obtained films were reduced to varying degrees, which shows that the chain extenders glycidyl methacrylate and 2-imidazolidinone used in the present invention can play a role in improving the mechanical properties of the material, and the technical effect of the present invention can only be achieved within the components and dosage ratio of the chain extender provided by the present invention.

[0123] Compared with Example 5, Comparative Examples 4 and 5 changed the components and dosage ratio of the plasticizer, but the mechanical properties of the obtained films were reduced to varying degrees, which shows that the plasticizer used in the present invention will not reduce the strength of the polymer and affect its mechanical properties, while the common plasticizer acetyl tributyl citrate cannot achieve this technical effect.

[0124] Compared with Example 6, Comparative Examples 6 and 7 changed the components and dosage ratio of the inorganic filler, but the mechanical properties of the obtained film were significantly reduced, which shows that the inorganic filler in the present invention has a huge impact on the mechanical properties of the material, not all inorganic fillers can achieve the technical effect of the present invention, and the components and dosage ratios of the inorganic filler in the present invention have been optimized.

[0125] The above embodiments are merely illustrative of the preparation method of the present invention, and are not intended to limit the present invention. Any person skilled in the art may not modify the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the technical concept provided by the present invention are still covered by the claims of the present invention.

Claims

1. A degradable bamboo fiber PBAT material, characterized in that: It includes the following components and their weight parts: 20-40 parts of bamboo fiber, 40-70 parts of PBAT, 5-10 parts of chain extender, 1-3 parts of nucleating agent, 5-8 parts of plasticizer, 10-15 parts of inorganic filler, 1-3 parts of coupling agent, 2-5 parts of lubricant, 3-5 parts of polyethylene grafted maleic anhydride; The chain extender is composed of glycidyl methacrylate and 2-imidazolidinone in a mass ratio of 31-35:7-11; the plasticizer is composed of dibutyl phthalate, dibutyl sebacate, and epoxidized dioctyl tetrahydrophthalate in a mass ratio of 9-13:2-6:25-29; the lubricant is composed of α-hydroxy fatty acid and calcium stearate in a mass ratio of 19-22:11-15; and the coupling agent is one of vinyl trimethoxy silane, γ-aminopropyl triethoxy silane, and vinyl triethoxy silane.

2. The degradable bamboo fiber PBAT material according to claim 1, characterized in that: The particle size of the bamboo fiber is 400-1000 mesh; the number average molecular weight of the PBAT is greater than 100, and the melt index is 3-10 / 10min.

3. The degradable bamboo fiber PBAT material according to claim 1, characterized in that: The nucleating agent in the degradable bamboo fiber PBAT material is sebacic acid diphenyl dihydrazide.

4. The degradable bamboo fiber PBAT material according to claim 1, characterized in that: The inorganic filler in the degradable bamboo fiber PBAT material is composed of silicon dioxide and mica powder in a mass ratio of 2-5:7-11; the particle size of the inorganic filler is 200-400nm.

5. The method for preparing a film made of degradable bamboo fiber PBAT material according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Dry the bamboo fiber at 80-150°C for 15-30 minutes, add it to a hot mixer together with the inorganic filler, add the atomized coupling agent at 50-100rpm and 90-110°C, and mix well; S2. Continue to add lubricant, chain extender, nucleating agent, polyethylene grafted maleic anhydride into the hot mixer, heat to 110-120 ° C and melt; S3. Continue to add PBAT and plasticizer to the hot mixer, heat to 135°C, stir at a speed of 150-200rpm for 20-35min, mix well, and cool to 40-50°C at a speed of 50-100rpm to obtain a premix; S4. The premix obtained in step S3 is put into a twin-screw extruder for extrusion, cooling, and pelletizing to obtain a masterbatch; S5. The masterbatch obtained in step S4 is blown into a film by a film blowing machine to obtain a degradable bamboo fiber PBAT film.

6. The method for preparing a film made of degradable bamboo fiber PBAT material according to claim 5, characterized in that: In step S4, the extrusion temperature of the twin-screw extruder is 145-165° C., and the screw speed is 50-100 rpm; in step S5, the screw temperature of the film blowing machine is 140-165° C., the die head temperature is 170-180° C., and the film thickness is 7-10 μm.

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