A biodegradable environment-friendly plastic material and a preparation method thereof

Abstract

The present application relates to the technical field of plastics, and particularly relates to a biodegradable environment-friendly plastic material and a preparation method thereof. The environment-friendly plastic material comprises the following components in parts by weight: polybutylene succinate 70-80 parts, modified pullulan 6-13 parts, filler 10-20 parts, plasticizer 1-2 parts, compatibilizer 0.5-1 part, and lubricant 0.1-0.5 part. The environment-friendly plastic material has excellent degradation, ultraviolet aging resistance, heat resistance and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, and in particular to a biodegradable and environmentally friendly plastic material and its preparation method. Background Technology

[0002] With the continued rise in global plastic consumption, the "white pollution" problem caused by traditional petroleum-based plastics has become a serious ecological and environmental challenge. These plastics are difficult to degrade in the natural environment, can persist for hundreds of years, causing persistent damage to soil, water, and marine ecosystems, and threatening biological and human health through the food chain. Against this backdrop, the development of biodegradable and environmentally friendly plastics is considered one of the key pathways to alleviate plastic pollution at its source, promote a circular economy, and achieve sustainable development. At the end of their lifespan, these materials can be decomposed by microorganisms into water, carbon dioxide or methane, and biomass under specific environmental conditions (such as composting, soil, and water), returning to the natural cycle.

[0003] However, from laboratory concept to large-scale practical application, biodegradable plastics face multiple performance barriers that must be overcome. The core challenge lies in how to achieve efficient and controllable biodegradation without sacrificing the material's essential performance characteristics. This cannot be encompassed by a simple "degradable" label; rather, it is a complex engineering project involving the systematic balancing and optimization of the material's overall performance.

[0004] First, mechanical properties are fundamental to plastics as structural or packaging materials. Many early bio-based or biodegradable plastics, such as polyhydroxyalkanoates (PHA) and polylactic acid (PLA), often suffer from problems such as high brittleness, insufficient toughness, poor impact resistance, or difficulty in balancing strength and modulus. These poor mechanical properties limit their use in packaging films, daily necessities, and even agricultural mulch films—fields requiring strength and flexibility—making them unable to completely replace traditional polyethylene (PE) and polypropylene (PP). Therefore, significantly improving the tensile strength, elongation at break, tear resistance, and toughness of materials while maintaining biodegradability through copolymerization, blending, nanocompositing, or plasticizing is currently the primary focus of research and development.

[0005] Secondly, UV resistance directly affects the lifespan and reliability of materials in outdoor applications. Whether used for outdoor tableware, agricultural mulch, or exposed to sunlight during storage and transportation, plastic materials are subject to UV radiation from sunlight. UV radiation causes polymer molecular chain breakage (photodegradation) or cross-linking, leading to surface chalking, discoloration, embrittlement, and a sharp decline in mechanical properties. Many biodegradable polyesters (such as PLA and PBS) inherently have weak UV resistance. Without modification, they may prematurely age and break down before fulfilling their intended function, leading not only to failure but also to microplastic contamination due to premature brittleness. Therefore, developing biodegradable systems with excellent UV shielding or stabilization capabilities is a prerequisite for long-term outdoor use.

[0006] Furthermore, heat aging resistance is crucial to a material's stability during processing, storage, and certain usage environments (such as hot filling and short-term high-temperature exposure). For example, PLA has a relatively low glass transition temperature and is prone to deformation at temperatures above 60°C. Its insufficient heat distortion temperature limits its application in heat-resistant applications. Simultaneously, the thermal history during processing (such as melt extrusion and injection molding) can trigger thermal degradation, affecting the performance of the final product. Good thermal stability requires not only a high heat distortion temperature and melt strength in the material itself but also often necessitates the addition of appropriate heat stabilizers to inhibit thermo-oxidative degradation during processing and use, ensuring performance retention.

[0007] To address the aforementioned issues, this invention provides a biodegradable and environmentally friendly plastic material with excellent overall performance. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, the primary objective of this invention is to provide a biodegradable and environmentally friendly plastic material with excellent degradability, UV aging resistance, heat resistance and mechanical properties.

[0009] Another objective of this invention is to provide a simple method for preparing a biodegradable and environmentally friendly plastic material.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A biodegradable and environmentally friendly plastic material.

[0012] By weight, it includes the following components: 70-80 parts of polybutylene terephthalate, 6-13 parts of modified pullulan, 10-20 parts of filler, 1-2 parts of plasticizer, 0.5-1 part of compatibilizer, and 0.1-0.5 parts of lubricant;

[0013] The preparation process of the modified pullulan is as follows:

[0014] (1) Add pullulan to water, heat and hydrate to obtain pullulan solution;

[0015] (2) Chicoric acid was added to the pullulan polysaccharide solution in step (1), and the reaction was carried out under the action of 4-dimethylaminopyridine to obtain the modified pullulan polysaccharide.

[0016] Preferably, the heating temperature in step (1) is 50-60℃ and the heating time is 0.5-1h; the hydration time is 3-5h.

[0017] Preferably, the mass ratio of pullulan, chicoric acid, and 4-dimethylaminopyridine in step (2) is 1:(0.1-0.3):(0.05-0.08).

[0018] Preferably, the reaction in step (2) is carried out at a temperature of 40-50°C for 1-2 hours.

[0019] Preferably, the preparation process of the filler is as follows:

[0020] Talc powder was added to an aqueous solution of silane coupling agent, heated to react, and then decanoic acid was added and stirred to obtain the filler.

[0021] Preferably, the mass ratio of talc, silane coupling agent, and decanoic acid is 1:(0.1-0.4):(0.01-0.05); the concentration of the aqueous solution of the silane coupling agent is 15-20 wt%; and the silane coupling agent is KH-550.

[0022] Preferably, the heating reaction temperature is 70-80℃ and the time is 1-2h; the stirring temperature is 80-90℃ and the time is 1-2h.

[0023] Preferably, the plasticizer is tributyl citrate or polycaprolactone diol; the compatibilizer is maleic anhydride-grafted poly(1,2-propanediol adipate) or maleic anhydride-grafted polylactic acid; and the lubricant is zinc stearate or ethylene bis-stearamide.

[0024] The preparation method of the above-mentioned biodegradable and environmentally friendly plastic material includes the following steps:

[0025] The raw materials are mixed evenly according to the stated weight proportions, and then melt-granulated, blown into film, and made into bags.

[0026] Preferably, the temperature of the twin-screw extruder during the melt granulation process is 140-180°C.

[0027] The present invention has the following advantages over the prior art:

[0028] 1. The environmentally friendly plastic material of this invention comprises the following components: polybutylene terephthalate, modified pullulan, filler, plasticizer, compatibilizer, and lubricant. Experimental results show that this environmentally friendly plastic material has excellent degradability, UV aging resistance, heat resistance, and mechanical properties.

[0029] 2. This invention improves the degradability, UV aging resistance, and mechanical properties of materials by adding modified pullulan. Specifically, the modified pullulan prepared by reacting the hydroxyl groups in pullulan with the carboxyl groups in chicoric acid effectively improves the UV aging resistance of materials. This is because the phenolic hydroxyl groups and double bonds of chicoric acid have free radical scavenging capabilities, which can capture oxygen free radicals generated during the processing or use of plastic materials, inhibiting the oxidative degradation of molecular chains; at the same time, the phenolic hydroxyl groups can absorb ultraviolet light, reducing the photo-aging damage of plastics caused by ultraviolet light. The aromatic ring of chicoric acid undergoes π-π stacking with the terephthalate segment in polybutylene terephthalate (PBST), enhancing the interfacial bonding force and improving the mechanical properties of plastic products. In addition, pullulan has strong hydrophilicity and poor compatibility with PBST; after modification, its hydrophilicity is reduced, improving its compatibility with PBST. Moreover, pullulan is a natural biodegradable polysaccharide that can be degraded and utilized by microorganisms in the soil. It can provide a penetration pathway for microorganisms, accelerate the erosion of microbial plastic materials, shorten the biodegradation cycle of plastics, and is more environmentally friendly.

[0030] 3. This invention improves the heat resistance and mechanical properties of materials by adding fillers. Specifically, after talc powder is modified with a silane coupling agent and decanoic acid, its dispersibility in plastic materials is better. The long-chain alkyl groups of decanoic acid reduce the friction between talc powder and polybutylene terephthalate melt, reducing powder agglomeration. The hydrophobic coating layer formed by decanoic acid avoids melt bubble defects caused by water absorption by talc powder, effectively improving the heat resistance and mechanical properties of plastic materials. Attached Figure Description

[0031] Figure 1 The image shows the infrared spectrum of the modified pullulan obtained in Example 1. Curve a is the infrared spectrum of the modified pullulan, and curve b is the infrared spectrum of the pullulan.

[0032] Figure 2 This is a SEM image of the packing material prepared in Example 4 of the present invention. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field. Test methods in the following embodiments that do not specify specific experimental conditions are generally performed according to conventional experimental conditions or experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention are commercially available.

[0034] Example 1

[0035] A modified pullulan polysaccharide is prepared as follows:

[0036] (1) Add pullulan to water, heat at 55°C for 0.7 h, and then hydrate at room temperature for 4 h to obtain pullulan solution;

[0037] (2) Chicoric acid and DMAP were added to the pullulan polysaccharide solution in step (1) with a mass ratio of pullulan polysaccharide, chicoric acid and 4-dimethylaminopyridine (DMAP) of 1:0.2:0.07. The reaction was carried out under a nitrogen atmosphere at 45°C for 1.5 h. After the reaction was completed, the mixture was dialyzed for 72 h. The weight-average molecular weight cutoff of the dialysis bag was 10,000. The mixture was then freeze-dried to obtain the modified pullulan polysaccharide.

[0038] Example 2

[0039] A modified pullulan polysaccharide is prepared as follows:

[0040] (1) Add pullulan to water, heat at 50°C for 1 hour, and then hydrate at room temperature for 3 hours to obtain pullulan solution;

[0041] (2) Chicoric acid and DMAP were added to the pullulan polysaccharide solution in step (1) with a mass ratio of pullulan polysaccharide, chicoric acid and DMAP of 1:0.1:0.05. The reaction was carried out at 40°C for 2 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was dialyzed for 72 hours. The weight-average molecular weight cutoff of the dialysis bag was 10,000. The mixture was then freeze-dried to obtain the modified pullulan polysaccharide.

[0042] Example 3

[0043] A modified pullulan polysaccharide is prepared as follows:

[0044] (1) Add pullulan to water, heat at 60°C for 0.5 h, and then hydrate at room temperature for 5 h to obtain pullulan solution;

[0045] (2) The mass ratio of pullulan, chicoric acid, and DMAP was 1:0.3:0.08.

[0046] Chicoric acid and DMAP were added to the pullulan polysaccharide solution in step (1), and the reaction was carried out at 50°C for 1 hour under a nitrogen atmosphere. After the reaction was completed, the solution was dialyzed for 72 hours. The weight-average molecular weight cutoff of the dialysis bag was 10,000. The solution was then freeze-dried to obtain the modified pullulan polysaccharide.

[0047] Example 4

[0048] A filler, prepared by the following method:

[0049] Talc powder, silane coupling agent, and decanoic acid were added to an 18wt% KH-550 aqueous solution at a mass ratio of 1:0.3:0.02. The reaction was carried out at 75℃ for 1.5h. After the reaction was completed, decanoic acid was added, the temperature was raised to 85℃ and stirred for 1.5h. The filler was obtained after filtration, washing and drying.

[0050] Example 5

[0051] A filler, prepared by the following method:

[0052] Talc powder, silane coupling agent, and decanoic acid were added to a 15wt% KH-550 aqueous solution at a mass ratio of 1:0.1:0.01. The reaction was carried out at 70℃ for 2 hours. After the reaction was completed, decanoic acid was added, the temperature was raised to 80℃ and stirred for 2 hours. The filler was obtained after filtration, washing and drying.

[0053] Example 6

[0054] A filler, prepared by the following method:

[0055] The filler was prepared by adding talc powder, silane coupling agent, and decanoic acid in a mass ratio of 1:0.4:0.05 to a 20wt% KH-550 aqueous solution and reacting at 80℃ for 1 hour. After the reaction was completed, decanoic acid was added, and the mixture was heated to 90℃ and stirred for 1 hour. The filler was then obtained by filtration, washing, and drying.

[0056] Example 7

[0057] A biodegradable and environmentally friendly plastic material, by weight, comprises the following components: 73 parts of polybutylene terephthalate, 9 parts of modified pullulan from Example 1, 15 parts of filler from Example 4, 1.5 parts of tributyl citrate, 0.8 parts of maleic anhydride-grafted poly(1,2-propanediol adipate), and 0.4 parts of zinc stearate.

[0058] The preparation method of the above-mentioned biodegradable and environmentally friendly plastic material includes the following steps:

[0059] According to the stated weight proportions, the raw materials are mixed evenly in a high-speed mixer, and then transferred to a twin-screw extruder for melt granulation at 140-180℃, followed by film blowing and bag making.

[0060] Example 8

[0061] A biodegradable and environmentally friendly plastic material, by weight, comprises the following components: 70 parts of polybutylene terephthalate, 6 parts of modified pullulan polysaccharide of Example 2, 10 parts of filler of Example 5, 1 part of polycaprolactone diol, 0.5 parts of maleic anhydride-grafted polylactic acid, and 0.1 parts of ethylene bis-stearamide.

[0062] The preparation method of the above-mentioned biodegradable and environmentally friendly plastic material includes the following steps:

[0063] According to the stated weight proportions, the raw materials are mixed evenly in a high-speed mixer, and then transferred to a twin-screw extruder for melt granulation at 140-180℃, followed by film blowing and bag making.

[0064] Example 9

[0065] A biodegradable and environmentally friendly plastic material, by weight, comprises the following components: 80 parts of polybutylene terephthalate, 13 parts of modified pullulan polysaccharide of Example 3, 20 parts of filler of Example 6, 2 parts of tributyl citrate, 1 part of maleic anhydride-grafted poly(1,2-propanediol adipate), and 0.5 parts of zinc stearate.

[0066] The preparation method of the above-mentioned biodegradable and environmentally friendly plastic material includes the following steps:

[0067] According to the stated weight proportions, the raw materials are mixed evenly in a high-speed mixer, and then transferred to a twin-screw extruder for melt granulation at 140-180℃, followed by film blowing and bag making.

[0068] Comparative Example 1

[0069] Based on Example 7, pullulan was used to replace the modified pullulan in Example 1 to form Comparative Example 1.

[0070] Comparative Example 2

[0071] Based on Example 7, talc powder was used to replace the filler in Example 4 to form Comparative Example 2.

[0072] Experimental Example 1

[0073] The modified pullulan polysaccharide obtained in Example 1 was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 1 As shown.

[0074] Figure 1This is the infrared spectrum of the modified pullulan obtained in Example 1. Curve a represents the infrared spectrum of the modified pullulan, and curve b represents the infrared spectrum of the pullulan. Compared to regular pullulan, the modified pullulan exhibits a higher infrared spectrum at 1730 cm⁻¹. -1 The characteristic peak of the C=O stretching vibration of the ester bond appears; at 1600 cm⁻¹ -1 1510 cm -1 The presence of an aromatic ring absorption peak indicates that the modification was successful, as it is a vibrational peak of the benzene ring skeleton of chicoric acid.

[0075] The packing material prepared in Example 4 was tested by scanning electron microscopy (SEM), and the results are as follows: Figure 2 As shown.

[0076] Experiment Example 2

[0077] The properties of the materials prepared in the examples and comparative examples were tested, and the specific test indicators are as follows:

[0078] The degradability of the materials prepared in the examples and comparative examples was tested in accordance with GB / T20197-2006, as shown in Table 1.

[0079] The tensile strength and elongation at break of the materials prepared in the examples and comparative examples were tested according to GB / T 1040.3-2006 at a tensile rate of 2 mm / min, as shown in Table 1.

[0080] The heat resistance performance was measured by the retention rate of tensile strength after the heat resistance test. The heat resistance test conditions were: 55℃±2℃, 75% relative humidity, and 400h. The tensile strength change rate was calculated as (tensile strength after heat aging treatment / original tensile strength of the specimen) × 100%, as shown in Table 1.

[0081] The UV aging resistance was measured by the retention rate of tensile strength after UV aging test. The UV aging test conditions were: irradiation with xenon arc lamp for 72 hours, and the tensile strength change rate was calculated as (tensile strength after UV aging treatment / original tensile strength of the sample) × 100%, as shown in Table 1.

[0082] Table 1

[0083]

[0084] As shown in Table 1, compared with Comparative Example 1, the material prepared in Example 7 exhibits superior degradability, UV aging resistance, and mechanical properties. The above experimental results demonstrate that the addition of modified pullulan polysaccharide in this invention can improve the degradability, UV aging resistance, and mechanical properties of the material. Specific analysis is as follows:

[0085] Modified pullulan, prepared by reacting the hydroxyl groups in pullulan with the carboxyl groups in chicoric acid, can effectively improve the UV aging resistance of materials. This is because the phenolic hydroxyl groups and double bonds of chicoric acid have free radical scavenging capabilities, which can capture oxygen free radicals generated during the processing or use of plastic materials, inhibiting the oxidative degradation of molecular chains; at the same time, the phenolic hydroxyl groups can absorb ultraviolet light, reducing the photo-aging damage of plastics caused by ultraviolet light. The aromatic ring of chicoric acid undergoes π-π stacking with the terephthalate segment in polybutylene terephthalate (PBST), enhancing interfacial bonding and improving the mechanical properties of plastic products. In addition, pullulan is highly hydrophilic and has poor compatibility with PBST; after modification, its hydrophilicity is reduced, improving its compatibility with PBST. Moreover, pullulan is a natural biodegradable polysaccharide that can be degraded and utilized by microorganisms in the soil, providing a penetration pathway for microorganisms, accelerating the erosion of microbial plastic materials, shortening the biodegradation cycle of plastics, and making it more environmentally friendly.

[0086] Compared with Comparative Example 2, the material obtained in Example 7 exhibits superior heat resistance and mechanical properties. The above experimental results demonstrate that the addition of fillers in this invention can improve the heat resistance and mechanical properties of the material. Specific analysis is as follows: Talc powder, after modification with a silane coupling agent and decanoic acid, shows better dispersibility in plastic materials. The long-chain alkyl groups of decanoic acid reduce the friction between talc powder and the polybutylene terephthalate melt, reducing powder agglomeration. The hydrophobic coating layer formed by decanoic acid avoids melt bubble defects caused by water absorption by talc powder, effectively improving the heat resistance and mechanical properties of the plastic material.

[0087] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A biodegradable and environmentally friendly plastic material, characterized in that, By weight, it includes the following components: 70-80 parts of polybutylene terephthalate, 6-13 parts of modified pullulan, 10-20 parts of filler, 1-2 parts of plasticizer, 0.5-1 part of compatibilizer, and 0.1-0.5 parts of lubricant; The preparation process of the modified pullulan is as follows: (1) Add pullulan to water, heat and hydrate to obtain pullulan solution; (2) Add chicoric acid to the pullulan polysaccharide solution from step (1) and react under the action of 4-dimethylaminopyridine to obtain the modified pullulan polysaccharide; The mass ratio of pullulan, chicoric acid, and 4-dimethylaminopyridine in step (2) is 1:(0.1-0.3):(0.05-0.08). The preparation process of the filler is as follows: Talc powder was added to an aqueous solution of silane coupling agent, heated to react, and then decanoic acid was added and stirred to obtain the filler.

2. The biodegradable and environmentally friendly plastic material according to claim 1, characterized in that, The heating temperature in step (1) is 50-60℃ and the time is 0.5-1h; the hydration time is 3-5h.

3. The biodegradable and environmentally friendly plastic material according to claim 1, characterized in that, The reaction in step (2) is carried out at a temperature of 40-50℃ for 1-2 hours.

4. The biodegradable and environmentally friendly plastic material according to claim 1, characterized in that, The mass ratio of talc, silane coupling agent, and decanoic acid is 1:(0.1-0.4):(0.01-0.05); the concentration of the aqueous solution of the silane coupling agent is 15-20 wt%; and the silane coupling agent is KH-550.

5. The biodegradable and environmentally friendly plastic material according to claim 1, characterized in that, The heating reaction is carried out at a temperature of 70-80℃ for 1-2 hours; the stirring is carried out at a temperature of 80-90℃ for 1-2 hours.

6. The biodegradable and environmentally friendly plastic material according to claim 1, characterized in that, The plasticizer is tributyl citrate or polycaprolactone diol; the compatibilizer is maleic anhydride-grafted poly(1,2-propanediol adipate) or maleic anhydride-grafted polylactic acid; the lubricant is zinc stearate or ethylene bis-stearamide.

7. A method for preparing a biodegradable and environmentally friendly plastic material according to any one of claims 1-6, characterized in that, Includes the following steps: The raw materials are mixed evenly according to the stated weight proportions, and then melt-granulated, blown into film, and made into bags.

8. The method for preparing the biodegradable and environmentally friendly plastic material according to claim 7, characterized in that, The temperature of the twin-screw extruder during the melt granulation process is 140-180℃.

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