Environment-friendly modified high-strength material of gutta-percha and preparation method thereof

Abstract

The application belongs to the technical field of polylactic acid composite materials, and particularly relates to an environment-friendly modified high-strength material of eucommia ulmoides gum and a preparation method thereof. The environment-friendly modified high-strength material of eucommia ulmoides gum comprises the following raw materials in parts by weight: polylactic acid 60-70 parts, polybutylene adipate terephthalate 20-30 parts, eucommia ulmoides gum 10-15 parts, reinforcing agent 1-5 parts, flame-retardant filler 4-7 parts, compatibilizer 1-3 parts, lubricant 2-5 parts, and antioxidant 0.3-0.5 parts. The material has excellent mechanical properties, thermal stability, hydrophobicity, barrier properties and flame-retardant properties.

Description

Technical Field

[0001] This invention belongs to the field of polylactic acid composite material technology, specifically relating to an environmentally friendly high-strength material modified with Eucommia ulmoides gum and its preparation method. Background Technology

[0002] Polylactic acid (PLA) is a biodegradable thermoplastic polyester polymerized from lactic acid. It boasts advantages such as being environmentally friendly, non-toxic, and biocompatible, making it promising for applications in packaging, medical, and automotive fields. However, PLA's inherent brittleness, poor impact resistance, and insufficient thermal stability limit its widespread use in engineering. Polybutylene terephthalate (PBAT) is a flexible, biodegradable polyester that complements PLA's properties; blending the two can improve PLA's flexibility to some extent. However, PLA and PBAT are thermodynamically incompatible systems, and direct blending results in poor interfacial bonding and compatibility, making it difficult to achieve a perfect balance between high strength and high toughness in practical applications.

[0003] To address these issues, researchers explored various modification strategies. On one hand, they improved the interfacial bonding between the PLA / PBAT phases by adding compatibilizers, thereby enhancing the compatibility and mechanical properties of the blend. On the other hand, they modified the PLA / PBAT blend by adding inorganic fillers, which could improve the material's crystallinity and thermal properties to some extent. However, while these methods improve individual properties, they often fail to simultaneously meet the demands for mechanical strength, toughness, flame retardancy, and barrier properties, leaving considerable room for improvement in overall performance.

[0004] Eucommia gum (EUG) is a natural polymer material derived from the Eucommia ulmoides tree, possessing unique dual properties of rubber and plasticity and excellent biodegradability. Current technologies often achieve toughening modification by blending EUG with PLA, but the addition of EUG can affect the mechanical properties and thermal stability of PLA to varying degrees, and there is also a problem of poor compatibility between EUG and PLA. Therefore, how to fully utilize the toughening advantages of EUG while maintaining good mechanical strength and thermal stability is a pressing technical challenge in this field.

[0005] Against this backdrop, developing an environmentally friendly composite material that can simultaneously improve the mechanical properties, flame retardant properties, barrier properties, and thermal stability of PLA / PBAT blends has significant practical implications and market value. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, the first objective of this invention is to provide an environmentally friendly high-strength material modified with Eucommia ulmoides gum, which has excellent mechanical properties, thermal stability, hydrophobicity, barrier properties and flame retardant properties.

[0007] The second objective of this invention is to provide a method for preparing an environmentally friendly high-strength material modified with Eucommia ulmoides gum, which is simple to operate.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An environmentally friendly high-strength material modified with Eucommia ulmoides gum, comprising the following raw materials in parts by weight: 60-70 parts polylactic acid, 20-30 parts polybutylene terephthalate adipate, 10-15 parts Eucommia ulmoides gum, 1-5 parts reinforcing agent, 4-7 parts flame retardant filler, 1-3 parts compatibilizer, 2-5 parts lubricant, and 0.3-0.5 parts antioxidant; The preparation process of the reinforcing agent is as follows: (1) Add jute fiber to an alkaline solution, soak, purify, and obtain alkaline-treated jute fiber; add the alkaline-treated jute fiber to a mixed solution of silane coupling agent and ethanol, stir, purify, and obtain pretreated jute fiber; (2) The pretreated jute fiber is added to N,N-dimethylformamide, and then 1-phenylvinylborate pinacol ester and initiator are added. The mixture is heated and reacted, and then purified to obtain the reinforcing agent.

[0009] The reinforcing agent of this invention achieves highly efficient functional modification of jute fibers through a multi-step synergistic effect. Specifically, firstly, the jute fibers are treated with alkali to remove surface pectin, wax, and some hemicellulose, exposing a large number of hydroxyl active sites and improving surface roughness. Then, the alkali-treated jute fibers undergo hydrolysis and condensation reactions with a silane coupling agent in an ethanol system, forming stable Si-O-cellulose covalent bonds on the hydroxyl groups of the jute fiber surface, completing fiber surface activation and introducing polymerizable double bonds. Finally, under the action of an initiator, 1-phenylvinylborate pinacol ester undergoes a free radical copolymerization grafting reaction with the double bonds introduced by the silane coupling agent, grafting hydrophobic groups containing benzene rings and borate ester functional groups onto the surface of the jute fibers.

[0010] Preferably, in step (1), the ratio of jute fiber, alkaline solution, silane coupling agent, and ethanol is 1g:(20-25)mL:(0.4-1)mL:(18-20)mL; the alkaline solution is a 15-20wt% sodium hydroxide aqueous solution; the silane coupling agent is vinyltriethoxysilane; the soaking temperature is 60-70℃ and the time is 3-5h; the stirring time is 3-5h.

[0011] Preferably, in step (2), the mass ratio of the pretreated jute fiber, 1-phenylvinylborate pinacol ester, and initiator is 1:(0.1-0.2):(0.005-0.01); the initiator is azobisisobutyronitrile; the heating reaction temperature is 80-90℃, and the time is 1-3h.

[0012] Preferably, the preparation process of the flame-retardant filler is as follows: (a) Pretreated montmorillonite was added to anhydrous ethanol, and then 2-methylthio-4,6-diaminopyrimidine was added. The mixture was stirred and purified to obtain amino-modified montmorillonite. (b) The amino-modified montmorillonite was added to N,N-dimethylformamide, followed by the addition of mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. After stirring and heating, the flame-retardant filler was obtained after purification.

[0013] The flame-retardant filler of the present invention is prepared by the following method: First, montmorillonite is pretreated to expand the interlayer spacing and reduce hydrophilicity. Then, 2-methylthio-4,6-diaminopyrimidine is loaded onto the surface of the pretreated montmorillonite using hydrogen bonding and electrostatic adsorption. Under the catalysis of triethylamine, the carboxyl groups of mercaptosuccinic acid undergo an amidation reaction with the amino groups on the surface of montmorillonite to form stable amide bonds, thereby constructing a multifunctional synergistic structure of "layered inorganic framework-nitrogen-sulfur heterocycle-thiol group" on the surface of montmorillonite.

[0014] Preferably, in step (a), the mass ratio of 2-methylthio-4,6-diaminopyrimidine to pretreated montmorillonite is 1:(20-30); the stirring temperature is 40-50℃ and the stirring time is 3-5h.

[0015] Preferably, the pretreated montmorillonite is prepared by adding montmorillonite to deionized water, then adding octadecyltrimethylammonium chloride, heating to react, and purifying to obtain the final product.

[0016] Preferably, the mass ratio of montmorillonite to octadecyltrimethylammonium chloride is 1:(0.01-0.05); the heating reaction temperature is 80-90℃ and the time is 1-2h.

[0017] Preferably, in step (b), the mass ratio of amino-modified montmorillonite, mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide is 1:(0.1-0.2):(0.4-0.5):(0.02-0.05):(0.01-0.04); the stirring time is 0.5-1 h; and the heating reaction temperature is 50-60 °C for 3-5 h.

[0018] Preferably, the weight-average molecular weight of the Eucommia ulmoides gum is (1.5-2) × 10⁻⁶. 5 Da; the polylactic acid is poly-L-lactic acid or poly-D-lactic acid; the compatibilizer is maleic anhydride or glycidyl methacrylate; the lubricant is ethylene bis-stearamide or oleamide; the antioxidant is antioxidant 168 or antioxidant 1098.

[0019] The preparation method of the above-mentioned environmentally friendly eucommia gum modified high-strength material includes the following steps: The raw materials are mixed evenly, and then melt-extruded, granulated, dried, blown into film, shaped, and wound up to obtain the final product.

[0020] Preferably, the temperatures of each section of the extruder during melt extrusion are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 175-185℃, and the die head temperature 175-180℃.

[0021] Compared with the prior art, the main advantages of the present invention are as follows: 1. This invention provides an environmentally friendly high-strength material modified with Eucommia ulmoides gum, comprising polylactic acid, polybutylene terephthalate-adipate, Eucommia ulmoides gum, reinforcing agent, flame-retardant filler, compatibilizer, lubricant, and antioxidant. This material possesses excellent mechanical properties, thermal stability, hydrophobicity, barrier properties, and flame-retardant properties.

[0022] 2. This invention improves the mechanical properties and hydrophobicity of the material by adding a reinforcing agent. The reinforcing agent reduces the surface polarity of the fiber and, through the pinacol ester group of phenylboronic acid, forms hydrogen bonds and coordination bonds with the hydroxyl, carboxyl, and ester bonds in the PLA and PBAT molecular chains. This significantly enhances the interfacial bonding between the fiber and the matrix, improves the compatibility of the two phases, and reduces interfacial defects and stress concentration. Simultaneously, the high rigidity and highly oriented structure of jute fiber can effectively withstand external forces, improving the tensile strength, elongation at break, and impact resistance of the material. Furthermore, the surface grafting structure reduces the hydrophilicity of jute fiber, inhibits water absorption and deterioration, and improves the stability of the material.

[0023] 3. This invention improves the flame retardant properties, barrier properties, and thermal stability of materials by adding flame-retardant fillers. The montmorillonite in this flame-retardant filler has a layered structure, forming a dense char layer during combustion, achieving physical barrier against heat, oxygen, and combustible gases. The nitrogen element in the pyrimidine ring releases inert gas upon heating, diluting the concentration of combustible gases and inhibiting the spread of combustion. The disulfide elements in the methylthio and mercapto groups can efficiently capture active free radicals generated during combustion, interrupting the combustion chain reaction. The synergistic effect of these three elements constructs an NS-layered barrier system, achieving highly efficient flame retardancy and effectively solving the problems of easy combustion, easy dripping, and high smoke density of PLA / PBAT, thus improving the flame retardant properties of the material. Furthermore, the improved hydrophobicity of this flame-retardant filler reduces the water absorption rate of the material, and its layered structure simultaneously enhances the material's barrier properties against oxygen and water vapor. The inorganic skeleton and nitrogen-sulfur heterocyclic structure of montmorillonite can inhibit the thermo-oxidative degradation of polyester molecular chains, thereby improving the processing stability of the material. Attached Figure Description

[0024] Figure 1Here is a SEM image of the reinforcing agent obtained in Example 1; Figure 2 This is a SEM image of the flame-retardant filler obtained in Example 4. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to specific embodiments. However, those skilled in the art should understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the reagents or instruments used are all conventional products obtained through commercial channels.

[0026] In the preparation examples of this invention, the diameter of jute fibers is 8-10 μm.

[0027] (a) Preparation example Preparation Example 1 An enhancing agent, prepared as follows: (1) The ratio of jute fiber, sodium hydroxide aqueous solution, vinyltriethoxysilane and ethanol is 1g:22mL:0.7mL:19mL. The jute fiber is added to a sodium hydroxide aqueous solution with a mass fraction of 18wt%, soaked at 65℃ for 4h, taken out, washed and dried to obtain alkali-treated jute fiber; the alkali-treated jute fiber is added to a mixed solution of vinyltriethoxysilane and ethanol, stirred at room temperature for 4h, taken out, washed and dried to obtain pretreated jute fiber; (2) With a mass ratio of pretreated jute fiber, 1-phenylvinylborate pinacol ester, and AIBN of 1:0.15:0.008, the pretreated jute fiber was added to N,N-dimethylformamide (DMF), followed by the addition of 1-phenylvinylborate pinacol ester (CAS: 143825-84-7) and azobisisobutyronitrile (AIBN). The mixture was reacted at 85°C for 2 hours, filtered, washed, and dried to obtain the reinforcing agent. The SEM image of the reinforcing agent is shown below. Figure 1 .

[0028] Preparation Example 2 An enhancing agent, prepared as follows: (1) The ratio of jute fiber, sodium hydroxide aqueous solution, vinyltriethoxysilane and ethanol is 1g:20mL:0.4mL:18mL. The jute fiber is added to a sodium hydroxide aqueous solution with a mass fraction of 15wt%, soaked at 60℃ for 5h, taken out, washed and dried to obtain alkali-treated jute fiber; The alkali-treated jute fiber is added to a mixed solution of vinyltriethoxysilane and ethanol, stirred at room temperature for 3h, taken out, washed and dried to obtain pretreated jute fiber; (2) The pretreated jute fiber, 1-phenylvinylborate pinacol ester, and AIBN were added to DMF in a mass ratio of 1:0.1:0.005. Then, 1-phenylvinylborate pinacol ester and AIBN were added. The mixture was reacted at 80°C for 3 hours, filtered, washed, and dried to obtain the reinforcing agent.

[0029] Preparation Example 3 An enhancing agent, prepared as follows: (1) Jute fiber, sodium hydroxide aqueous solution, vinyltriethoxysilane and ethanol were used in a ratio of 1g:25mL:1mL:20mL. Jute fiber was added to a sodium hydroxide aqueous solution with a mass fraction of 20wt%, soaked at 70℃ for 3h, removed, washed and dried to obtain alkali-treated jute fiber; the alkali-treated jute fiber was added to a mixed solution of vinyltriethoxysilane and ethanol, stirred at room temperature for 5h, removed, washed and dried to obtain pretreated jute fiber; (2) The pretreated jute fiber, 1-phenylvinylborate pinacol ester, and AIBN were added to DMF in a mass ratio of 1:0.2:0.01. Then, 1-phenylvinylborate pinacol ester and AIBN were added. The mixture was reacted at 90°C for 1 hour, filtered, washed, and dried to obtain the reinforcing agent.

[0030] Preparation Example 4 A flame-retardant filler, the preparation process of which is as follows: (a) Montmorillonite and octadecyltrimethylammonium chloride were added to deionized water at a mass ratio of 1:0.03, followed by the addition of octadecyltrimethylammonium chloride. The mixture was reacted at 85°C for 1.5 h, filtered, washed, and dried to obtain pretreated montmorillonite. Pretreated montmorillonite was added to anhydrous ethanol at a mass ratio of 1:25, followed by the addition of 2-methylthio-4,6-diaminopyrimidine. The mixture was stirred at 45°C for 4 h, filtered, washed, and dried to obtain amino-modified montmorillonite. (b) The amino-modified montmorillonite, mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide were added to DMF in a mass ratio of 1:0.15:0.45:0.04:0.03. Mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide were then added. After stirring for 0.7 h, the mixture was reacted at 55 °C for 4 h. The mixture was then filtered, washed, and dried to obtain the flame-retardant filler. The SEM image of the flame-retardant filler is shown below. Figure 2 .

[0031] Preparation Example 5 A flame-retardant filler, the preparation process of which is as follows: (a) Montmorillonite and octadecyltrimethylammonium chloride were added to deionized water at a mass ratio of 1:0.01, followed by the addition of octadecyltrimethylammonium chloride. The mixture was reacted at 80°C for 2 hours, filtered, washed, and dried to obtain pretreated montmorillonite. Pretreated montmorillonite was added to anhydrous ethanol at a mass ratio of 1:20, followed by the addition of 2-methylthio-4,6-diaminopyrimidine. The mixture was stirred at 40°C for 5 hours, filtered, washed, and dried to obtain amino-modified montmorillonite. (b) The amino-modified montmorillonite, mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide were added to DMF in a mass ratio of 1:0.1:0.4:0.02:0.01. Mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were then added. After stirring for 0.5 h, the mixture was reacted at 50 °C for 5 h. The mixture was then filtered, washed, and dried to obtain the flame-retardant filler.

[0032] Preparation Example 6 A flame-retardant filler, the preparation process of which is as follows: (a) Montmorillonite and octadecyltrimethylammonium chloride were added to deionized water at a mass ratio of 1:0.05, followed by the addition of octadecyltrimethylammonium chloride. The mixture was reacted at 90°C for 1 h, filtered, washed, and dried to obtain pretreated montmorillonite. Pretreated montmorillonite was added to anhydrous ethanol at a mass ratio of 1:30, followed by the addition of 2-methylthio-4,6-diaminopyrimidine. The mixture was stirred at 50°C for 3 h, filtered, washed, and dried to obtain amino-modified montmorillonite. (b) The amino-modified montmorillonite, mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide were added to DMF in a mass ratio of 1:0.2:0.5:0.05:0.04. Mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were then added. After stirring for 1 h, the mixture was reacted at 60 °C for 3 h. The mixture was then filtered, washed, and dried to obtain the flame-retardant filler.

[0033] (II) Implementation Examples Example 1 An environmentally friendly high-strength material modified with Eucommia ulmoides gum, comprising the following raw materials in parts by weight: 64 parts poly-L-lactic acid, 21 parts polybutylene terephthalate-adipate, and Eucommia ulmoides gum (Mw=2×10). 515 parts of Da, 1 part of the reinforcing agent of Preparation Example 1, 4 parts of the flame retardant filler of Preparation Example 4, 2 parts of glycidyl methacrylate, 3 parts of ethylene bis-stearamide, and 0.4 parts of antioxidant 168.

[0034] The preparation method of the above-mentioned environmentally friendly eucommia gum modified high-strength material includes the following steps: According to the stated weight proportions, the raw materials are added to a high-speed mixer and mixed at 400 rpm for 8 minutes at room temperature. Then, the mixture is transferred to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 175-185℃, and the die head temperature 175-180℃. The screw speed is 200 rpm. After granulation, the mixture is dried at 70℃ for 6 hours and then blown into a film. The blown film temperature is set at 170℃, the blow-up ratio is 3, and the traction ratio is 5. After cooling and setting, the mixture is wound up to obtain the final product.

[0035] Example 2 An environmentally friendly high-strength material modified with Eucommia ulmoides gum comprises the following raw materials in parts by weight: 60 parts poly-D-lactic acid, 20 parts polybutylene terephthalate-adipate, and Eucommia ulmoides gum (Mw=1.8×10). 5 12 parts of Da, 3 parts of the reinforcing agent of Preparation Example 2, 6 parts of the flame retardant filler of Preparation Example 5, 1 part of maleic anhydride, 2 parts of oleic amide, and 0.3 parts of antioxidant 1098.

[0036] The preparation method of the above-mentioned environmentally friendly eucommia gum modified high-strength material includes the following steps: According to the stated weight proportions, the raw materials are added to a high-speed mixer and mixed at 300 rpm for 10 minutes at room temperature. Then, the mixture is transferred to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 175-185℃, and the die head temperature 175-180℃. The screw speed is 150 rpm. After granulation, the mixture is dried at 60℃ for 8 hours and then blown into a film. The blown film temperature is set at 170℃, the blow-up ratio is 3, and the traction ratio is 5. After cooling and setting, the mixture is wound up to obtain the final product.

[0037] Example 3 An environmentally friendly high-strength material modified with Eucommia ulmoides gum comprises the following raw materials in parts by weight: 70 parts poly-D-lactic acid, 30 parts polybutylene terephthalate-adipate, and Eucommia ulmoides gum (Mw=1.5×10). 5 10 parts of Da, 5 parts of the reinforcing agent of Preparation Example 3, 7 parts of the flame retardant filler of Preparation Example 6, 3 parts of glycidyl methacrylate, 5 parts of oleamide, and 0.5 parts of antioxidant 168.

[0038] The preparation method of the above-mentioned environmentally friendly eucommia gum modified high-strength material includes the following steps: According to the stated weight proportions, the raw materials are added to a high-speed mixer and mixed at 500 rpm for 5 minutes at room temperature. Then, the mixture is transferred to a twin-screw extruder for melt extrusion. The temperatures of each section of the extruder are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 175-185℃, and the die head temperature 175-180℃. The screw speed is 250 rpm. After granulation, the mixture is dried at 70℃ for 5 hours and then blown into a film. The blown film temperature is set at 170℃, the blow-up ratio is 3, and the traction ratio is 5. After cooling and setting, the mixture is wound up to obtain the final product.

[0039] (III) Comparative Example Comparative Example 1 The difference between this comparative example and Example 1 is that the pretreated jute fiber from Example 1 is used instead of the reinforcing agent.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that the pretreated montmorillonite from Preparation Example 4 is used instead of the flame-retardant filler.

[0041] (iv) Test Cases Experimental Example 1 The reinforcing agent obtained in Preparation Example 1 and the flame-retardant filler obtained in Preparation Example 4 were characterized by scanning electron microscopy (SEM). The microstructure results are as follows: Figures 1-2 As shown.

[0042] Figure 1 This is a SEM image of the reinforcing agent obtained in Example 1. Observation shows that after alkali treatment, activation with a silane coupling agent, and graft modification with 1-phenylvinylborate pinacol ester, the fiber surface is coated with an organic modified layer.

[0043] Figure 2 This is a SEM image of the flame-retardant filler obtained in Example 4. Observation shows that after cationic surfactant intercalation, aminopyrimidine loading, and mercaptosuccinic acid amidation modification, a large amount of modified active components are attached to the surface of the montmorillonite sheets.

[0044] Experimental Example 2 Tensile strength and elongation at break: Tested according to GB / T1040.3-2006 "Determination of tensile properties of plastics - Part 3: Test conditions for films and sheets", and the results are shown in Table 1; Impact strength: Each material was cut into rectangular strips of 1cm×8cm, and a 2mm deep notch was punched on the side. The test was conducted at room temperature using an XJUD-digital display pendulum impact tester. The results are shown in Table 1. Thermogravimetric analysis: Thermogravimetric analysis was performed on each material using a thermogravimetric analyzer. The weight of each material was 8 mg. The test conditions were: under a nitrogen atmosphere, the temperature was raised from room temperature to 600℃ at a heating rate of 20℃ / min, and the initial decomposition temperature was recorded. The results are shown in Table 1. Water vapor transmission rate: Water vapor barrier performance was tested according to GB / T 1037-2021, and the results are shown in Table 1; Oxygen permeability: Oxygen barrier performance was tested according to GB / T 1038.1-2022, and the results are shown in Table 1; Flame retardant performance: The limiting oxygen index (LOI) was tested according to GB / T 2406.2-2009 "Determination of flammability of plastics by oxygen index method - Part 2: Room temperature test", and the results are shown in Table 1. Contact angle: The contact angle of the samples was measured using the seat drop method: At room temperature, the material (10 mm × 20 mm) of the example or comparative example was fixed on the sample stage of the contact angle meter. Deionized water (10 μL) was slowly and vertically dropped onto the material using a microsyringe and the contact angle image was taken. After 50 seconds, the contact angle was recorded at room temperature using a contact angle analyzer. Two independent measurements were performed on each material, and the average value was calculated. The results are shown in Table 1.

[0045] Table 1 As shown in Table 1, the tensile strength, elongation at break, and impact strength of Examples 1-3 are significantly higher than those of Comparative Example 1, indicating that the reinforcing agent of the present invention can significantly improve the mechanical properties of the material after grafting modification.

[0046] The initial decomposition temperatures of Examples 1-3 were significantly higher than those of Comparative Example 2, indicating that the flame-retardant filler of the present invention, after modification with nitrogen-sulfur heterocyclic rings, can effectively inhibit the thermo-oxidative degradation of polyester molecular chains and improve the thermal stability of the material. The water vapor permeability and oxygen permeability of Examples 1-3 were significantly lower than those of Comparative Example 2, indicating that unmodified montmorillonite cannot construct an effective "maze effect," and its poor dispersibility leads to a significant reduction in barrier performance.

[0047] The contact angles of Examples 1-3 are significantly higher than those of Comparative Examples 1 and 2, indicating that the reinforcing agent and flame-retardant filler of the present invention can synergistically improve the surface hydrophobicity of the membrane material.

[0048] In summary, the dual functionalization of the reinforcing agent and flame-retardant filler in this invention, combined with the synergistic effect of Eucommia ulmoides gum toughening and PBAT flexible matrix, achieves a comprehensive improvement in the material's mechanical properties, thermal stability, hydrophobicity, barrier properties, and flame-retardant properties. It solves the problems of difficulty in achieving both high strength and good toughness, and insufficient flame-retardant and barrier properties in the prior art, and has a significant synergistic effect.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. An environmentally friendly high-strength material modified with Eucommia ulmoides gum, characterized in that, The raw materials include the following parts by weight: 60-70 parts of polylactic acid, 20-30 parts of polybutylene terephthalate-adipate, 10-15 parts of eucommia gum, 1-5 parts of reinforcing agent, 4-7 parts of flame retardant filler, 1-3 parts of compatibilizer, 2-5 parts of lubricant, and 0.3-0.5 parts of antioxidant. The preparation process of the reinforcing agent is as follows: (1) Add jute fiber to an alkaline solution, soak, purify, and obtain alkaline-treated jute fiber; add the alkaline-treated jute fiber to a mixed solution of silane coupling agent and ethanol, stir, purify, and obtain pretreated jute fiber; (2) The pretreated jute fiber is added to N,N-dimethylformamide, and then 1-phenylvinylborate pinacol ester and initiator are added. The mixture is heated and reacted, and then purified to obtain the reinforcing agent.

2. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 1, characterized in that, In step (1), the ratio of jute fiber, alkaline solution, silane coupling agent, and ethanol is 1g:(20-25)mL:(0.4-1)mL:(18-20)mL; the alkaline solution is a 15-20wt% sodium hydroxide aqueous solution; the silane coupling agent is vinyltriethoxysilane; the soaking temperature is 60-70℃ and the time is 3-5h; the stirring time is 3-5h.

3. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 1, characterized in that, In step (2), the mass ratio of the pretreated jute fiber, 1-phenylvinylborate pinacol ester, and initiator is 1:(0.1-0.2):(0.005-0.01); the initiator is azobisisobutyronitrile; the heating reaction temperature is 80-90℃ and the time is 1-3h.

4. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 1, characterized in that, The preparation process of the flame-retardant filler is as follows: (a) Pretreated montmorillonite was added to anhydrous ethanol, and then 2-methylthio-4,6-diaminopyrimidine was added. The mixture was stirred and purified to obtain amino-modified montmorillonite. (b) The amino-modified montmorillonite was added to N,N-dimethylformamide, followed by the addition of mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. After stirring and heating, the flame-retardant filler was obtained after purification.

5. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 4, characterized in that, In step (a), the mass ratio of 2-methylthio-4,6-diaminopyrimidine to pretreated montmorillonite is 1:(20-30); the stirring temperature is 40-50℃ and the stirring time is 3-5h.

6. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 5, characterized in that, The pretreated montmorillonite is prepared by adding montmorillonite to deionized water, then adding octadecyltrimethylammonium chloride, heating to react, and purifying to obtain the final product.

7. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 6, characterized in that, The mass ratio of montmorillonite to octadecyltrimethylammonium chloride is 1:(0.01-0.05); the heating reaction temperature is 80-90℃ and the time is 1-2h.

8. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 4, characterized in that, In step (b), the mass ratio of amino-modified montmorillonite, mercaptosuccinic acid, triethylamine, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, and N-hydroxysuccinimide is 1:(0.1-0.2):(0.4-0.5):(0.02-0.05):(0.01-0.04); the stirring time is 0.5-1 h; and the heating reaction temperature is 50-60 °C for 3-5 h.

9. The environmentally friendly high-strength material modified with Eucommia ulmoides gum according to claim 1, characterized in that, The weight-average molecular weight of the Eucommia ulmoides gum is (1.5-2)×10. 5 Da; the polylactic acid is poly-L-lactic acid or poly-D-lactic acid; the compatibilizer is maleic anhydride or glycidyl methacrylate; the lubricant is ethylene bis-stearamide or oleamide; the antioxidant is antioxidant 168 or antioxidant 1098.

10. A method for preparing an environmentally friendly high-strength material modified with Eucommia ulmoides gum according to any one of claims 1-9, characterized in that, Includes the following steps: The raw materials are mixed evenly, and then melt-extruded, granulated, dried, blown into film, shaped, and wound up to obtain the final product. During melt extrusion, the temperatures of each section of the extruder are set as follows: Zone 1 150-160℃, Zone 2 160-170℃, Zone 3 170-180℃, Zone 4 175-185℃, and the die head temperature 175-180℃, with a screw speed of 150-250 rpm. The drying temperature is 60-70℃, and the time is 5-8 hours; The blown film temperature is 170°C, the blow-up ratio is 3, and the traction ratio is 5.

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