A pbset / lignin composite material and a preparation method and application thereof

Abstract

The application provides a PBSeT / lignin composite material and a preparation method and application thereof. The application uses PBSeT and lignin as raw materials, adds a compatibilizer and an optional coupling agent, and improves the dispersibility of lignin in the PBSeT resin by the synergistic improvement of the compatibility of lignin and PBSeT through the chemical reaction of the compatibilizer and the physical action of the coupling agent. The PBSeT-based composite biodegradable material modified by the compatibilization has good toughness and thermal performance, and is suitable for agricultural mulching films and packaging materials.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable films, and relates to a PBSeT / lignin composite material, its preparation method and application. Background Technology

[0002] While plastics have brought many conveniences to people, they have also caused problems such as the energy crisis and plastic pollution. Biodegradable plastics are derived from agricultural crops and degrade into carbon dioxide and water through composting, microorganisms, light, and water vapor, making them a green, recyclable, and environmentally friendly material. Developing biodegradable plastics is an important way to solve these problems. PBSeT (polybutylene sebacic acid terephthalate) is a biodegradable material with good toughness and processing properties.

[0003] Patent CN114456488A discloses a tear-resistant PBSeT / PP / HDPE composite material. The method involves first melt-blending PP and HDPE, then adding synthesized PBSeT for further blending. At a PBSeT content of 12%, the elongation at break is 357.65%. Patent CN113396039A discloses a method for preparing starch blends. This method uses PBAT as the main resin, adds starch and other additives for melt blending, and then blow-moldes to obtain a film, with a maximum elongation at break reaching 539%. Patent CN103703077A discloses a biodegradable film. This method uses PBAT and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as the resin matrix, adds fillers and additives such as calcium carbonate and talc, and performs melt extrusion blow molding. The resulting biodegradable film has a maximum elongation at break of 907%.

[0004] Lignin is the second most abundant biomass resource in the plant kingdom, after cellulose. In industry, lignin is a byproduct of pulping, papermaking, and bioethanol production. It is a sustainable and inexpensive biomass material. However, lignin utilization is low, with most of it being discharged into rivers as waste liquid or concentrated and incinerated, resulting in significant resource waste every year. Due to its structural characteristics, lignin possesses advantages such as safety, non-toxicity, and low cost, as well as properties like UV absorption, biodegradability, antibacterial activity, and antioxidant properties, making it a potential reinforcing filler in composite materials. Summary of the Invention

[0005] This invention provides a PBSeT / lignin composite material and its preparation method, which improves the compatibility of PBSeT with lignin compounds. The compatibility is synergistically improved through chemical reactions and physical interactions between the components, thereby improving the mechanical properties of the product and reducing costs. The composite material provided by this invention has a high content of lignin compounds and is a completely degradable, environmentally friendly bioplastic suitable for packaging materials, agricultural films, and other fields.

[0006] One objective of this invention is to provide a PBSeT / lignin composite material comprising a mixture of PBSeT, lignin compounds, compatibilizers, and / or their reaction products, wherein the compatibilizers are selected from organic compounds containing epoxy functional groups.

[0007] According to the present invention, in the PBSeT / lignin composite material:

[0008] The lignin compound can be a commonly used lignin compound in the art, preferably at least one of alkali lignin, enzymatically hydrolyzed lignin, and lignin sulfonate;

[0009] The compatibilizer is selected from at least one of epoxidized soybean oil and copolymers containing epoxy functional groups; wherein, the copolymer containing epoxy functional groups is preferably an acrylic acid-styrene copolymer containing epoxy functional groups, such as commercially available products ADR-4468, ADR-4400, etc.

[0010] According to the present invention, the PBSeT / lignin composite material optionally further comprises at least one of a coupling agent and an opening agent, wherein the coupling agent is selected from at least one of silane coupling agents; the opening agent is selected from fatty amide compounds, preferably from at least one of erucamide and oleamide; based on 100 parts by weight of the total weight of the PBSeT and lignin compounds, the coupling agent is 0 to 5 parts and the opening agent is 0 to 1 part; preferably, based on 100 parts by weight of the total weight of the PBSeT and lignin compounds, the coupling agent is 0 to 3 parts and the opening agent is 0.05 to 0.5 parts.

[0011] According to the present invention, in the PBSeT / lignin composite material, based on a total weight of 100 parts by weight of PBSeT and lignin compounds, the PBSeT comprises 50-99 parts, the lignin compounds comprise 1-50 parts, and the compatibilizer comprises 0.1-12 parts; preferably, the PBSeT comprises 70-90 parts, the lignin compounds comprise 10-30 parts, and the compatibilizer comprises 1-10 parts.

[0012] The second objective of this invention is to provide a method for preparing the above-mentioned PBSeT / lignin composite material, comprising: premixing components including the PBSeT, lignin compounds, and compatibilizer, followed by melt extrusion and granulation to obtain the PBSeT / lignin composite material.

[0013] According to the present invention, in the preparation method of the PBSeT / lignin composite material:

[0014] The PBSeT and lignin compounds need to be dried beforehand. The drying process can be carried out using drying equipment and conditions commonly used in the art. Preferably, the drying conditions are: drying at 60-70°C for 20-24 hours.

[0015] Optionally, at least one of a coupling agent and an opening agent is added during the premixing process, wherein the coupling agent is selected from at least one of silane coupling agents; and the opening agent is selected from fatty amide compounds, preferably at least one of erucamide and oleamide.

[0016] According to the present invention, in the preparation method of the PBSeT / lignin composite material, the melt extrusion can be carried out using melt extrusion equipment and melt extrusion process commonly used in the art, preferably on a twin-screw extruder with a screw speed of 100-140 rpm; the melt extrusion temperature is 100-180°C, preferably 110-170°C.

[0017] According to a specific embodiment of the present invention, the preparation method of the PBSeT / lignin composite material can specifically adopt the following preparation process:

[0018] (1) Pretreatment of raw materials: Place 50-99 parts of PBSeT and 1-50 parts of lignin compounds in a forced-air drying oven and dry at 60-70℃ for 20-24h to remove moisture from the raw materials;

[0019] (2) Mixing of raw materials: Add 50-99 parts of the dried PBSeT, 1-50 parts of lignin, 0.1-12 parts of compatibilizer, 0-5 parts of coupling agent, and 0-1 parts of opening agent to a high-speed mixer and mix evenly to obtain a premix. The speed is 1000-2000 r / min and the mixing time is 10-20 min.

[0020] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The screws of the twin-screw extruder rotate in the same direction, with a length-to-diameter ratio of 35-45:1, a feeding speed of 10-14 rpm, and a screw speed of 100-140 rpm. The temperature of each zone is controlled at: Zone 1 100-125℃, Zone 2 130-160℃, Zone 3 140-170℃, Zone 4 140-170℃, Zone 5 140-170℃, Zone 6 130-160℃, and Zone 7 130-160℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder and then extruded and granulated to obtain PBSeT / lignin composite material.

[0021] This invention utilizes a chemical reaction between the epoxy functional groups in the compatibilizer and the hydroxyl and / or carboxyl groups in PBSeT and / or lignin compounds to achieve compatibilization, forming a PBSeT-compatibilizer-lignin microbranched structure. In the PBSeT / lignin composite material provided by this invention, a coupling agent can be optionally added according to actual application needs. The synergistic compatibilization effect of the compatibilizer and the physical action of the coupling agent improves the compatibility between PBSeT and lignin compounds, thereby enhancing the mechanical properties of the composite material.

[0022] The third objective of this invention is to provide a PBSeT-based biodegradable film, prepared from the above-mentioned PBSeT / lignin composite material or the PBSeT / lignin composite material obtained by the above-mentioned preparation method.

[0023] The fourth objective of this invention is to provide a method for preparing the above-mentioned PBSeT-based biodegradable film, which includes the step of extruding and casting the PBSeT / lignin composite material into a film.

[0024] According to the present invention, the extrusion casting can be carried out using extrusion casting equipment and extrusion casting conditions commonly used in the art. Preferably, the extrusion casting conditions are: temperature of 100-180°C, more preferably 110-170°C; screw speed of 40-80 rpm; and traction speed of 0.1-2.5 m / min.

[0025] According to a specific embodiment of the present invention, the preparation method of the PBSeT-based biodegradable film can specifically adopt the following preparation process:

[0026] Extrusion casting film formation: The masterbatch is placed in an extrusion casting machine, and the temperature of each zone is controlled as follows: Zone 1 100-120℃, Zone 2 115-145℃, Zone 3 140-160℃, Zone 4 140-160℃, Zone 5 145-165℃, Zone 6 145-165℃, Zone 7 155-180℃, Zone 8 155-180℃. The screw speed is 40-80 rpm, and the traction rate is 0.1-2.5 m / min. After cooling and curling, the PBSeT-based biodegradable film is obtained. The thickness of the obtained film is 30-150 μm.

[0027] The fifth objective of this invention is to provide the application of the above-mentioned PBSeT / lignin composite material or the above-mentioned PBSeT-based biodegradable film in agricultural mulch films and packaging materials.

[0028] Using the above technical solution, the PBSeT-based biodegradable film obtained by the present invention has good toughness and low cost, good processing performance, and the optimized performance of tensile strength and elongation at break can reach 18MPa and 1159%, respectively.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. In this invention, an organic compound containing an epoxy functional group is added as a compatibilizer to improve the compatibility between PBSeT and lignin compounds, thereby improving the mechanical properties of the composite material.

[0031] 2. The components in the composite material of this invention are environmentally friendly materials. When considering the performance and cost of the composite material, the optimal performance of the tensile strength and elongation at break of the composite material can reach 18MPa and 1159%, respectively.

[0032] 3. The preparation process provided by this invention is simple and easy to implement, and can be easily industrialized, with broad application prospects. Attached Figure Description

[0033] Figures 1-2 The images show the infrared spectra of the PBSeT / lignin biodegradable composite film prepared in Example 1 of this invention, as well as PBSeT, epoxidized soybean oil (ESO), and enzymatically hydrolyzed lignin. Detailed Implementation

[0034] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0035] The testing instruments and conditions used in this embodiment are as follows:

[0036] The tensile properties of PBSeT / lignin biodegradable composite films were determined using a universal testing machine (MTSE42.503) in accordance with the national standard GB / T1040.3-2006.

[0037] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0038] Example 1:

[0039] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0040] (2) Mixing of raw materials: 70 parts of dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 2 parts of epoxidized soybean oil, 0.5 parts of KH550 coupling agent, and 0.05 parts of erucamide are added to a high-speed mixer and mixed evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0041] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 12 rpm, the screw speed is 120 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0042] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch is placed in an extrusion casting machine. The temperatures of each zone are controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed is 60 rpm, and the traction rate is 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film is obtained with a thickness of 120 μm. The tensile strength is 16 MPa, and the elongation at break can reach 1097%.

[0043] The infrared characterization of the prepared PBSeT / lignin biodegradable composite film is shown in the attached figure. Figures 1-2 As shown in the figure, the hydroxyl groups of lignin are at 3419 cm⁻¹. -1 There is a broad stretching vibration peak at 823 cm⁻¹, and the absorption peak of the epoxy groups in epoxidized soybean oil is at 823 cm⁻¹.-1 and 724cm -1 It can be observed that the absorption peaks of epoxy groups and hydroxyl groups in PBSeT / lignin disappear, proving that the epoxy groups and hydroxyl groups have undergone a chemical reaction to form a PBSeT-compatibilizer-lignin microbranched structure.

[0044] Example 2:

[0045] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0046] (2) Mixing of raw materials: Add 70 parts of the dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 2 parts of epoxidized soybean oil, 0 parts of KH560 coupling agent, and 0.05 parts of erucamide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0047] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 12 rpm, the screw speed is 120 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0048] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch is placed in an extrusion casting machine. The temperatures of each zone are controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed is 60 rpm, and the traction rate is 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film is obtained with a thickness of 90 μm. The tensile strength is 13 MPa, and the elongation at break can reach 1050%.

[0049] Example 3:

[0050] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0051] (2) Mixing of raw materials: Add 70 parts of the dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 1 part of epoxidized soybean oil, 1 part of KH550 coupling agent, and 0.05 parts of erucamide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0052] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 11 rpm, the screw speed is 110 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0053] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 73 μm. The tensile strength of the film was measured to be 15 MPa, and the elongation at break reached 1149%.

[0054] Example 4:

[0055] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0056] (2) Mixing of raw materials: Add 70 parts of dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 4 parts of epoxidized soybean oil, 1 part of KH560 coupling agent, and 0.05 parts of erucamide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0057] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 11 rpm, the screw speed is 110 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0058] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 86 μm. The tensile strength of the film was measured to be 14 MPa, and the elongation at break reached 1187%.

[0059] Example 5:

[0060] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0061] (2) Mixing of raw materials: Add 70 parts of the dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 1 part of epoxidized soybean oil, 3 parts of KH550 coupling agent, and 0.05 parts of erucamide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0062] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 13 rpm, the screw speed is 130 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0063] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 102 μm. The tensile strength of the film was measured to be 13 MPa, and the elongation at break reached 1008%.

[0064] Example 6:

[0065] (1) Pretreatment of raw materials: 70 parts of PBSeT and 30 parts of enzymatically hydrolyzed lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0066] (2) Mixing of raw materials: Add 70 parts of the dried PBSeT, 30 parts of enzymatically hydrolyzed lignin, 2 parts of epoxidized soybean oil, 1 part of KH560 coupling agent, and 0.05 parts of erucamide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0067] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 12 rpm, the screw speed is 120 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0068] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 45 μm. The tensile strength of the film was measured to be 18 MPa, and the elongation at break reached 1159%.

[0069] Example 7:

[0070] (1) Pretreatment of raw materials: Place 80 parts of PBSeT and 20 parts of enzymatically hydrolyzed lignin in a forced-air drying oven and dry at 70°C for 20 hours to remove moisture from the raw materials.

[0071] (2) Mixing of raw materials: Add 80 parts of the dried PBSeT, 20 parts of enzymatically hydrolyzed lignin, 4 parts of ADR-4468 compatibilizer, 2 parts of KH570 coupling agent, and 0.1 parts of oleic amide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0072] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 11 rpm, the screw speed is 110 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0073] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 70 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 130 μm. The tensile strength of the film was measured to be 11 MPa, and the elongation at break reached 1092%.

[0074] Example 8:

[0075] (1) Pretreatment of raw materials: 80 parts of PBSeT and 20 parts of alkali lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0076] (2) Mixing of raw materials: Add 80 parts of the dried PBSeT, 20 parts of alkali lignin, 1 part of ADR-4400 compatibilizer, 2 parts of KH570 coupling agent, and 0.1 parts of oleic amide to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0077] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 12 rpm, the screw speed is 120 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0078] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 127 μm. The tensile strength of the film was measured to be 11 MPa, and the elongation at break reached 1124%.

[0079] Example 9:

[0080] (1) Pretreatment of raw materials: 90 parts of PBSeT and 10 parts of alkali lignin were placed in a forced-air drying oven and dried at 70°C for 20 hours to remove moisture from the raw materials.

[0081] (2) Mixing of raw materials: Add the above-mentioned dried PBSeT90 parts, alkali lignin 10 parts, ADR-4468 compatibilizer 2 parts, KH590 coupling agent 1 part, oleic amide 0.1 parts to a high-speed mixer and mix evenly to obtain a premix. The speed is 1600 r / min and the mixing time is 15 min.

[0082] (3) Extrusion granulation: The premixed material is added to a twin-screw extruder. The twin-screw extruder screws rotate in the same direction, with a length-to-diameter ratio of 40:1. The feeding speed is 12 rpm, the screw speed is 120 rpm, and the temperature of each zone is controlled at: Zone 1 115℃, Zone 2 150℃, Zone 3 155℃, Zone 4 155℃, Zone 5 155℃, Zone 6 150℃, and Zone 7 145℃. The material is effectively melted and mixed by the shearing action of the twin-screw extruder before extrusion granulation to obtain PBSeT / lignin composite material masterbatch.

[0083] (4) Extrusion Casting Film Formation: The PBSeT / lignin composite masterbatch was placed in an extrusion casting machine. The temperatures of each zone were controlled as follows: Zone 1 115℃, Zone 2 135℃, Zone 3 155℃, Zone 4 155℃, Zone 5 160℃, Zone 6 160℃, Zone 7 170℃, and Zone 8 170℃. The screw speed was 60 rpm, and the traction rate was 0.75 m / min. After cooling and curling, the PBSeT-based biodegradable film was obtained with a thickness of 125 μm. The tensile strength of the film was measured to be 12 MPa, and the elongation at break reached 1136%.

[0084] Comparative Example 1

[0085] The comparative example is a blend containing starch and PBAT disclosed in Chinese Patent CN113396039A, in which the maximum elongation at break in the disclosed example reaches 539%. The optimized tensile strength and elongation at break of the PBSeT / lignin composite materials prepared in Examples 1-10 of the present invention can reach 18 MPa and 1159%, respectively. The elongation at break of the blend in Comparative Example 1 is much lower than that of the present invention.

[0086] Comparative Example 2

[0087] The comparative example is a tear-resistant PBSeT / PP / HDPE composite material disclosed in Chinese patent CN114456488A. The elongation at break of the prepared material is 357.65%, which is much lower than that of Examples 1 to 10 of the present invention. Moreover, the PP and HDPE used are non-degradable materials, while the PBSeT and lignin selected in the present invention are degradable.

[0088] Comparative Example 3

[0089] In Comparative Example 3, a PBSeT / lignin composite material without compatibilizer and coupling agent was prepared using the same method as in Example 1. The tensile strength and elongation at break were 11 MPa and 997%, respectively. Compared with the material without compatibilizer, the PBSeT / lignin composite material with compatibilizer and coupling agent in Example 1 showed better performance.

Claims

1. A PBSeT / lignin composite material, comprising a mixture of PBSeT, lignin compounds, compatibilizers, and / or their reaction products, wherein the compatibilizers are selected from organic compounds containing epoxy functional groups; the PBSeT / lignin composite material further comprises at least one of a coupling agent and an opening agent, wherein the coupling agent is selected from at least one of silane coupling agents, and the opening agent is selected from fatty amide compounds.

2. The PBSeT / lignin composite material according to claim 1, characterized in that, The lignin compounds are selected from at least one of alkali lignin, enzymatically hydrolyzed lignin, and lignin sulfonates; and / or, The compatibilizer is selected from at least one of epoxidized soybean oil and copolymers containing epoxy functional groups.

3. The PBSeT / lignin composite material according to claim 2, characterized in that, The opening agent is selected from at least one of erucamide and oleamide; and / or, Based on a total weight of 100 parts by weight of the PBSeT and lignin compounds, the coupling agent comprises 0-5 parts and the opening agent comprises 0-1 parts.

4. The PBSeT / lignin composite material according to claim 3, characterized in that, Based on a total weight of 100 parts by weight of the PBSeT and lignin compounds, the coupling agent comprises 0 to 3 parts, and the opening agent comprises 0.05 to 0.5 parts.

5. The PBSeT / lignin composite material according to claim 1, characterized in that, Based on a total weight of 100 parts by weight of PBSeT and lignin compounds, the PBSeT comprises 50-99 parts, the lignin compounds comprise 1-50 parts, and the compatibilizer comprises 0.1-12 parts.

6. The PBSeT / lignin composite material according to claim 5, characterized in that, Based on a total weight of 100 parts by weight of PBSeT and lignin compounds, PBSeT comprises 70-90 parts, lignin compounds comprise 10-30 parts, and compatibilizer comprises 1-10 parts.

7. A process for the preparation of the PBSeT / lignin composite of any one of claims 1 to 6, comprising: The components, including PBSeT, lignin compounds, and compatibilizers, are premixed, melt-extruded, and granulated to obtain the PBSeT / lignin composite material.

8. The preparation method according to claim 7, characterized in that, The PBSeT and lignin compounds mentioned above require prior drying treatment; and / or, At least one of a coupling agent and an opening agent is added during the premixing process.

9. The preparation method according to claim 8, characterized in that, The drying conditions are 60~70℃ for 20~24 hours.

10. The preparation method according to claim 7, characterized in that, The melt extrusion is carried out on a twin-screw extruder; and / or, the melt extrusion is performed on a twin-screw extruder. The temperature of the melt extrusion is 100~180℃.

11. The preparation method according to claim 10, characterized in that, The screw speed is 100~140 rpm; and / or, The temperature of the melt extrusion is 110~170℃.

12. A PBSeT-based biodegradable film, prepared from the PBSeT / lignin composite material according to any one of claims 1 to 6 or the PBSeT / lignin composite material obtained by the preparation method according to any one of claims 7 to 11.

13. A method for preparing the PBSeT-based biodegradable film of claim 12, comprising the step of extruding and casting the PBSeT / lignin composite material into a film.

14. The method of claim 13, wherein, The conditions for the extrusion casting are as follows: The temperature is 100~180℃; and / or, The screw speed is 40~80 rpm; and / or, The traction speed is 0.1~2.5m / min.

15. The method of claim 14, wherein, The conditions for the extrusion casting are as follows: The temperature is 110~170℃; and / or, The screw speed is 40~80 rpm; and / or, The traction speed is 0.1~2.5m / min.

16. The application of a PBSeT / lignin composite material according to any one of claims 1 to 6 or a PBSeT-based biodegradable film according to claim 12 in agricultural mulch films and packaging materials.

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