Recycled ABS-based composite material and preparation method thereof

Abstract

The invention discloses a recycled ABS (Acrylonitrile Butadiene Styrene)-based composite material and a preparation method thereof, and relates to the technical field of high polymer material regeneration. The recycled ABS-based composite material is prepared from the following raw materials in parts by weight: 100 parts of waste ABS plastic, 2 to 5 parts of bifunctional macromolecular chain extender, 3 to 8 parts of functionalized nano filler, 0.5 to 2 parts of composite deodorant, 0.3 to 1 part of antioxidant, 0.1 to 0.5 part of stearic acid and 0.5 to 2 parts of ethylene glycol bis (3, 4-dihydroxyphenylboronic acid ester). The invention discloses a recycled ABS composite material and a preparation method thereof. Waste ABS is used as a raw material, a plurality of auxiliary agents are used as auxiliary materials, and the material is prepared through pretreatment, blending and other processes. The method has the advantages that the performance of the recycled material is improved, the pollution is reduced, the process is environment-friendly and efficient, the resource recycling is realized, the comprehensive performance of the prepared material is good, and the application field of the recycled ABS is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material regeneration, in particular to a composite material based on recycled ABS and a preparation method thereof. Background Art

[0002] ABS (acrylonitrile-butadiene-styrene copolymer), one of the world's most widely used thermoplastic engineering plastics, is widely used in electronics, automotive components, packaging, and other fields. However, with the surge in its consumption, a large amount of waste ABS plastic is difficult to directly recycle due to problems such as molecular chain breakage, oxidative degradation, and impurity contamination. Traditional landfill or incineration methods not only waste resources but also cause serious environmental pollution.

[0003] In the existing waste ABS recycling technology, patent CN202111560269.1 proposes to repair performance through in-situ chain extension reaction between chain extenders and molecular chain carboxyl functional groups. However, it only repairs the molecular chain for the carboxyl groups generated by aging, and does not fully consider the complex impurities such as oil stains, pigment residues, low molecular weight degradation products that may exist in waste ABS, as well as structural defects other than molecular chain breakage, such as cross-linking and changes in branching degree. Such limitations may lead to insufficient performance stability of recycled materials in special scenarios such as high temperature and high load, making it difficult to meet high-end application requirements. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a composite material based on recycled ABS and a preparation method thereof, which solves the problems of performance degradation, difficulty in removing impurities, obvious odor, uneven filler dispersion and poor interface compatibility in the recycling of waste ABS.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A composite material based on recycled ABS comprises the following raw materials in parts by weight: 100 parts of waste ABS plastic, 2-5 parts of a bifunctional macromolecular chain extender, 3-8 parts of a functionalized nanofiller, 0.5-2 parts of a composite deodorant, 0.3-1 parts of an antioxidant, 0.1-0.5 parts of stearic acid, and 0.5-2 parts of ethylene glycol bis(3,4-dihydroxyphenyl borate); The bifunctional macromolecular chain extender is a mixture of adipic acid dihydrazide (ADP) and ethylene glycol dimethacrylate (EGDMA) in a mass ratio of 1:1.

[0006] Furthermore, the waste ABS plastic has a particle size of ≤1 mm, a moisture content of ≤0.5% after cleaning, and contains 15-20 wt% acrylonitrile, 5-10 wt% butadiene, and 70-75 wt% styrene; the composite deodorant is a mixture of β-cyclodextrin and activated carbon in a mass ratio of 2:1; and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0007] Furthermore, the functionalized nanofiller is prepared in the following specific steps: A1. Dopamine hydrochloride was added to a Tris-HCl buffer solution to prepare a dopamine hydrochloride buffer solution; natural sodium montmorillonite was ground and passed through a 300-mesh sieve, then added to the dopamine hydrochloride buffer solution and stirred at 25°C for 24 hours; after the reaction, the mixture was transferred to a centrifuge tube, centrifuged for 10 minutes, and repeatedly washed with deionized water until the pH value of the washing solution reached 7. Finally, the washed montmorillonite was dried in a vacuum drying oven for 12 hours to obtain dopamine-modified montmorillonite; A2. Tetrabutyl titanate was added dropwise to an ethanol aqueous solution while stirring to form a uniform precursor solution; dopamine-modified montmorillonite was added to the above precursor solution, placed in a constant temperature water bath, and stirred at 60°C for 6 hours; after the reaction, the mixture was cooled to room temperature, centrifuged for 10 minutes, the supernatant was poured out, the precipitate was washed with anhydrous ethanol, and then the sample was placed in a vacuum drying oven and dried for 10 hours to obtain titanium dioxide-loaded montmorillonite; A3. Add silane coupling agent KH-570 to ethanol, then add deionized water, stir evenly, and let stand at room temperature for 30 minutes; add titanium dioxide-supported montmorillonite to the silane coupling agent KH-570 solution, transfer to a three-necked flask, and stir in a 90°C oil bath for 2 hours; after the reaction is completed, naturally cool to room temperature, centrifuge for 10 minutes to separate the modified montmorillonite, wash with ethanol, and finally place the sample in a vacuum drying oven for 8 hours to obtain KH-570-modified montmorillonite; A4. Place the KH-570-modified montmorillonite in a three-necked flask, add toluene as a solvent, and stir and disperse for 30 minutes; dissolve benzoyl peroxide in toluene to prepare an initiator solution, slowly drip it into the three-necked flask, stir in an 80°C oil bath for 30 minutes, add lactide monomer, continue heating to 120°C, and react under nitrogen protection for 4 hours; after the reaction, cool the mixture to room temperature, centrifuge for 10 minutes to remove the solvent, and wash with anhydrous ethanol. Place the product in a vacuum drying oven and dry it for 12 hours to obtain a functionalized nanofiller.

[0008] Furthermore, in step A1, the pH of the Tris-HCl buffer solution is 8.5, the concentration is 0.1 mol / L, and the concentration of the dopamine hydrochloride buffer solution is 2 g / L; the amounts of natural sodium montmorillonite and dopamine hydrochloride buffer solution are 10 g and 150 mL respectively; the reaction stirring speed is 300 r / min, the centrifugal speed is 8000 r / min, and the drying temperature is 60°C.

[0009] Furthermore, in step A2, ethanol and water are mixed in a volume ratio of 1:1; the amounts of tetrabutyl titanate, ethanol aqueous solution, and dopamine-modified montmorillonite are 3 g, 150 mL, and 10 g, respectively; the reaction stirring speed is 250 r / min, the centrifugal speed is 8000 r / min, the reaction mixture is washed three times with anhydrous ethanol, and the drying temperature is 70°C.

[0010] Furthermore, in step A3, the amounts of silane coupling agent KH-570, ethanol, deionized water, and titanium dioxide-loaded montmorillonite are 1.8 mL, 90 mL, 10 mL, and 8 g, respectively; the reaction stirring speed is 200 r / min, the centrifugal speed is 8000 r / min, the ethanol washing is performed 3 times, and the drying temperature is 80°C.

[0011] Furthermore, in step A4, the amounts of KH-570 modified montmorillonite and toluene were 8 g and 80 mL respectively; the amounts of benzoyl peroxide and toluene in the initiator were 0.8 g and 7 mL respectively; and the amount of lactide monomer was 1.6 g; the centrifugal speed was 8000 r / min, the product was washed with anhydrous ethanol three times, and the drying temperature was 60°C.

[0012] A preparation method based on recycled ABS composite material specifically comprises the following steps: S1. Pretreatment of waste ABS Crushing: Use a low-temperature crusher to crush the waste ABS into particles of 0.5~1mm; Cleaning: ultrasonic cleaning at 80℃ for 30min to remove impurities, centrifugal dehydration and vacuum drying at 70℃ for 6h; Characterization: Use FTIR to detect the absorption peak intensity of surface impurities to ensure the cleaning effect; S2, in-situ chain extension and nanocomposite blending Initial mixing: Mix the pretreated ABS with antioxidant and lubricant in a high-speed mixer at 60°C for 10 minutes to form a basic mixture; Plasma surface modification: Place the base mixture in a low-temperature plasma treatment device, using argon as the working gas, and treat for 3 to 5 minutes; Chain extension reaction: Add bifunctional macromolecular chain extender and dynamic covalent bond chain extender, transfer to the modified twin-screw extruder, set up a pressure-bearing closed cavity in the reaction section, and inject supercritical carbon dioxide (SC-CO2) at a pressure of 5-8 MPa through a high-pressure pump during the chain extension reaction. Set a temperature gradient and the material residence time is 3-5 minutes; Nanofiller and deodorant blending: Functionalized nanofiller and composite deodorant are injected simultaneously into the side feed port in the middle of the extruder, and nanoscale dispersion is achieved through the shear force of the screw; 3D gradient structure construction: The blended materials are injected into a mold with a gradient temperature field control. The mold temperature is gradually reduced by 5-10°C from the inlet to the outlet. At the same time, a pressure of 0.5-1 MPa is applied to orient the montmorillonite nanofillers and form a composite material body with a 3D gradient structure. S3, post-processing and performance optimization Microwave-assisted post-treatment: Place the green body in a special microwave drying device for 1-2 hours to achieve rapid drying and dynamic covalent bond rearrangement; Extrusion granulation: The pellet diameter is 2~3mm. After cooling, it is vacuum dried at 80℃ for 4h to remove residual moisture and unreacted small molecules to obtain recycled ABS products.

[0013] Furthermore, in the step S1, the pulverization temperature is ≤30°C; and the ultrasonic power is 300W.

[0014] Furthermore, in the step S2, the mixer speed is 800 r / min; the plasma treatment equipment power is 100~200 W; the screw extruder L / D is ≥30, the temperature gradient is: 180℃ / 195℃ / 210℃ / 220℃ / 215℃; the screw torque fluctuation is ≤±5Nm; in the step S3, the microwave power is 500~800 W.

[0015] Bifunctional macromolecular chain extender reaction: ABS molecular chains break at high temperature to produce carboxyl groups, and ADP hydrazide groups condense with carboxyl groups to form amide bonds, connecting the broken molecular chains and increasing the weight-average molecular weight.

[0016] Dynamic covalent chain extender reaction: In SC-CO2 medium, the borate ester bond reacts reversibly with the hydroxyl group on the ABS chain: At high temperatures, the bonds break reversibly, allowing the molecular chains to slip and reducing the melt viscosity; after cooling, the bonds are fixed to form a dynamic cross-linked network, which increases the elastic modulus of the material.

[0017] Synergistic effect of ADP and EGDMA: ADP preferentially repairs broken chains, restores the original chain structure of ABS, and reduces melt viscosity; EGDMA further extends the chain length and introduces cross-linking points, enhancing mechanical strength and thermal stability; the combination of the two realizes a "repair-extension-cross-linking" multi-stage reaction, taking into account both mechanical and processing properties.

[0018] The present invention provides a composite material based on recycled ABS and a preparation method thereof, which has the following beneficial effects: 1. Improved mechanical properties: Through the bifunctional macromolecular chain extender and supercritical carbon dioxide assisted chain extension reaction, the ABS molecular chain breakage defects are repaired. Combined with the 3D gradient structure formed by the directional arrangement of functional nanofillers, the tensile strength, impact toughness and heat resistance of the composite material are significantly improved, approaching the level of native ABS.

[0019] 2. High-efficiency deodorization and purification: The composite deodorizer effectively removes volatile organic compounds and odorous substances generated during the recycling process of waste ABS through physical adsorption and inclusion complexation, improves the odor of the material, and meets environmental protection standards and food contact grade application requirements.

[0020] 3. Enhanced compatibility and dispersibility: Low-temperature plasma surface modification pretreatment of ABS, combined with multi-layer modification of functionalized nanofillers, significantly improves the interfacial compatibility between the filler and the ABS matrix by introducing polar groups and polymer grafting, achieving nanoscale uniform dispersion and avoiding performance degradation caused by agglomeration.

[0021] 4. Environmentally friendly process and resource recycling: Energy-saving processes such as low-temperature crushing and microwave-assisted drying are used to reduce thermal degradation and energy consumption. No complex pretreatment equipment is required and it is compatible with existing twin-screw extrusion production lines, with lower energy consumption than traditional processes. Supercritical carbon dioxide is used as a green reaction medium and can be recycled and reused to reduce pollution. Recycling waste ABS can reduce the harm of plastic waste to the environment and promote the development of a circular economy for polymer materials. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] Example 1: Preparation of a composite material based on recycled ABS. The specific preparation steps are as follows: S1. Pretreatment of waste ABS Crushing: Use a low-temperature crusher at a temperature of ≤30°C to crush the waste ABS into particles of 0.5mm; Cleaning: Ultrasonic cleaning at 300W power and 80℃ hot water for 30min to remove impurities, centrifugal dehydration and vacuum drying at 70℃ for 6h; Characterization: Use FTIR to detect the absorption peak intensity of surface impurities to ensure the cleaning effect; S2, in-situ chain extension and nanocomposite blending Initial mixing: 100 parts of pretreated ABS, 0.3 parts of antioxidant, and 0.1 parts of stearic acid were mixed in a high-speed mixer at 800 r / min and 60°C for 10 minutes to form a basic mixture; Plasma surface modification: Place the base mixture in a low-temperature plasma treatment device, using argon as the working gas, a power of 100W, and treat for 3 minutes; Chain extension reaction: Add 2 parts of bifunctional macromolecular chain extender and 0.5 parts of ethylene glycol bis(3,4-dihydroxyphenyl borate), and transfer to a modified twin-screw extruder with a screw extruder L / D ≥ 30. The screw configuration is as follows: conveying section → shearing section → reaction section → devolatilization section. A pressure-bearing closed cavity is set in the reaction section. During the chain extension reaction, supercritical carbon dioxide is injected at a pressure of 5 MPa through a high-pressure pump. The temperature gradient is set at 180°C / 195°C / 210°C / 220°C / 215°C, and the material residence time is 3 minutes. Nanofiller and deodorant blending: 3 parts of functionalized nanofiller and 0.5 parts of composite deodorant are simultaneously injected into the side feed port in the middle of the extruder, and nano-scale dispersion is achieved through the screw shear force with torque fluctuation ≤±5Nm; 3D gradient structure construction: The blended materials are injected into a mold with a gradient temperature field control. The mold temperature is gradually reduced by 5°C from the inlet to the outlet. At the same time, a pressure of 0.5 MPa is applied to orient the montmorillonite nanofillers and form a composite body with a 3D gradient structure. S3, post-processing and performance optimization Microwave-assisted post-treatment: The green body is placed in a special microwave drying equipment with a power of 500W for 1 hour to achieve rapid drying and dynamic covalent bond rearrangement; Extrusion granulation: The pellets have a diameter of 2 mm and are cooled and then vacuum dried at 80°C for 4 h to remove residual moisture and unreacted small molecules to obtain recycled ABS products.

[0024] Example 2: Preparation of a composite material based on recycled ABS. The specific preparation steps are as follows: S1. Pretreatment of waste ABS Crushing: Use a low-temperature crusher at a temperature of ≤30°C to crush the waste ABS into particles of 1mm in size; Cleaning: Ultrasonic cleaning at 300W power and 80℃ hot water for 30min to remove impurities, centrifugal dehydration and vacuum drying at 70℃ for 6h; Characterization: Use FTIR to detect the absorption peak intensity of surface impurities to ensure the cleaning effect; S2, in-situ chain extension and nanocomposite blending Initial mixing: 100 parts of pretreated ABS, 1 part of antioxidant, and 0.5 parts of stearic acid were mixed in a high-speed mixer at 800 r / min and 60°C for 10 minutes to form a basic mixture; Plasma surface modification: Place the base mixture in a low-temperature plasma treatment device, using argon as the working gas, a power of 200W, and treat for 5 minutes; Chain extension reaction: Add 5 parts of bifunctional macromolecular chain extender and 2 parts of ethylene glycol bis(3,4-dihydroxyphenyl borate) and transfer to a modified twin-screw extruder with an L / D ≥ 30 and a screw configuration: conveying section → shearing section → reaction section → devolatilization section. A pressure-bearing closed cavity is set in the reaction section. During the chain extension reaction, supercritical carbon dioxide is injected at a pressure of 8 MPa through a high-pressure pump. The temperature gradient is set at 180°C / 195°C / 210°C / 220°C / 215°C, and the material residence time is 5 minutes. Nanofiller and deodorant blending: 8 parts of functional nanofiller and 2 parts of composite deodorant are simultaneously injected into the side feed port in the middle of the extruder, and nano-scale dispersion is achieved through the screw shear force with torque fluctuation ≤±5Nm; 3D gradient structure construction: The blended materials are injected into a mold with a gradient temperature field control. The mold temperature is gradually reduced by 10°C from the inlet to the outlet. At the same time, a pressure of 1 MPa is applied to align the montmorillonite nanofillers, forming a composite body with a 3D gradient structure. S3, post-processing and performance optimization Microwave-assisted post-treatment: The green body is placed in a special microwave drying equipment with a power of 800W for 2 hours to achieve rapid drying and dynamic covalent bond rearrangement; Extrusion granulation: The pellets have a diameter of 3 mm and are cooled and then vacuum dried at 80°C for 4 h to remove residual moisture and unreacted small molecules to obtain recycled ABS products.

[0025] Example 3: Preparation of a composite material based on recycled ABS. The specific preparation steps are as follows: S1. Pretreatment of waste ABS Crushing: Use a low-temperature crusher at a temperature of ≤30°C to crush the waste ABS into particles of 0.7mm; Cleaning: Ultrasonic cleaning at 300W power and 80℃ hot water for 30min to remove impurities, centrifugal dehydration and vacuum drying at 70℃ for 6h; Characterization: Use FTIR to detect the absorption peak intensity of surface impurities to ensure the cleaning effect; S2, in-situ chain extension and nanocomposite blending Initial mixing: 100 parts of pretreated ABS, 0.6 parts of antioxidant, and 0.3 parts of stearic acid were mixed in a high-speed mixer at 800 r / min and 60°C for 10 minutes to form a basic mixture; Plasma surface modification: Place the base mixture in a low-temperature plasma treatment device, using argon as the working gas, a power of 150W, and treat for 4 minutes; Chain extension reaction: Add 3 parts of bifunctional macromolecular chain extender and 1 part of dynamic covalent bond chain extender ethylene glycol bis(3,4-dihydroxyphenyl borate), and transfer to a modified twin-screw extruder with a screw extruder L / D ≥ 30. The screw configuration is as follows: conveying section → shearing section → reaction section → devolatilization section. A pressure-bearing closed cavity is set in the reaction section. During the chain extension reaction, supercritical carbon dioxide is injected at a pressure of 6 MPa through a high-pressure pump. The temperature gradient is set at 180°C / 195°C / 210°C / 220°C / 215°C, and the material residence time is 4 minutes. Nanofiller and deodorant blending: 5 parts of functionalized nanofiller and 1 part of composite deodorant are injected simultaneously into the side feed port in the middle of the extruder, and nano-scale dispersion is achieved through the screw shear force with torque fluctuation ≤±5Nm; 3D gradient structure construction: The blended materials are injected into a mold with a gradient temperature field control. The mold temperature is gradually reduced by 7°C from the inlet to the outlet. At the same time, a pressure of 0.7 MPa is applied to align the montmorillonite nanofillers, forming a composite body with a 3D gradient structure. S3, post-processing and performance optimization Microwave-assisted post-treatment: The green body is placed in a special microwave drying equipment with a power of 650W for 1.5 hours to achieve rapid drying and dynamic covalent bond rearrangement; Extrusion granulation: The pellets have a diameter of 2 mm and are cooled and then vacuum dried at 80°C for 4 h to remove residual moisture and unreacted small molecules to obtain recycled ABS products.

[0026] Example 4: Preparation of functionalized nanofillers. The specific preparation steps are as follows: A1. Dopamine hydrochloride was added to a Tris-HCl buffer solution with a pH of 8.5 and a concentration of 0.1 mol / L to prepare a dopamine hydrochloride buffer solution with a concentration of 2 g / L. Natural sodium montmorillonite was ground and passed through a 300-mesh sieve. 10 g of the solution was added to 150 mL of the dopamine hydrochloride buffer solution, and the mixture was stirred at 300 r / min at 25°C for 24 h. After the reaction, the mixture was transferred to a centrifuge tube, centrifuged at 8000 r / min for 10 min, and repeatedly washed with deionized water until the pH value of the washing solution reached 7. Finally, the washed montmorillonite was dried in a vacuum drying oven at 60°C for 12 h to obtain dopamine-modified montmorillonite. A2. Solution preparation: ethanol and water were mixed in a volume ratio of 1:1 to prepare an ethanol-water solution. 3 g of tetrabutyl titanate was added dropwise to 150 mL of the ethanol-water solution while stirring to form a uniform precursor solution. 10 g of dopamine-modified montmorillonite was added to 150 mL of the above precursor solution, placed in a constant temperature water bath, and stirred at 60 ° C at 250 r / min for 6 h. After the reaction, the mixture was cooled to room temperature, centrifuged at 8000 r / min for 10 min for solid-liquid separation, washed with anhydrous ethanol 3 times, and then the sample was placed in a vacuum drying oven at 70 ° C for 10 h to obtain titanium dioxide-loaded montmorillonite. A3. Add 1.8 mL of silane coupling agent KH-570 to 90 mL of ethanol, then add 10 mL of deionized water, stir evenly, and let stand at room temperature for 30 min; add 8 g of titanium dioxide-loaded montmorillonite to the silane coupling agent KH-570 solution, transfer to a three-necked flask, and stir in a 90°C oil bath at 200 r / min for 2 h; after the reaction is completed, cool naturally to room temperature, separate the modified montmorillonite by centrifugation at 8000 r / min for 10 min, wash three times with ethanol, and finally dry the sample in a vacuum drying oven at 80°C for 8 h to obtain KH-570 modified nanofiller; A4. Place 8g of KH-570-modified montmorillonite in a three-necked flask, add 80mL of toluene as a solvent, and stir and disperse for 30 minutes; dissolve 0.8g of benzoyl peroxide in 7mL of toluene to prepare an initiator solution, slowly drip it into the three-necked flask, stir in an 80℃ oil bath for 30 minutes, add 1.6g of lactide monomer, continue heating to 120℃, and react for 4 hours under nitrogen protection; after the reaction, cool the mixture to room temperature, centrifuge at 8000r / min for 10 minutes to remove the solvent, and wash with anhydrous ethanol three times. Place the product in a vacuum drying oven at 60℃ and dry it for 12 hours to obtain a functionalized nanofiller.

[0027] Comparative Example 1: Preparation of a composite material based on recycled ABS. The specific preparation steps are as follows: The remaining steps remained unchanged, except that the functionalized nanofiller of Example 3 was replaced by nano-montmorillonite without any treatment to prepare a composite material based on recycled ABS.

[0028] Comparative Example 2: Preparation of a composite material based on recycled ABS. The specific preparation steps are as follows: Q1. Pretreatment of waste ABS: Use traditional room temperature crushing to reduce the particle size to ≤1mm, and dry at 70℃ to reduce the moisture content to ≤1%; Q2. Blending and extrusion: The pretreated waste ABS and common chain extender diethylene oxide are directly added into a single-screw extruder. The extrusion temperature is kept constant at 200°C and the screw speed is 200 r / min for extrusion granulation.

[0029] Performance Testing Test items Test standards Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Izod notched impact strength (kJ / m²) GB / T1843-2008 22 24 26 20 15 Tensile strength (MPa) GB / T1040.1-2018 45 46 48 38 30 Flexural strength (MPa) GB / T9341-2008 58 60 63 50 40 Melt flow rate (230℃, 2.16kg) (g / 10min) ISO1133 15 17 20 10 7 The test results show that the recycled ABS composite materials in Examples 1-3, to which functionalized nanofillers are added and optimized processes are used, have significantly better Izod notched impact strength, tensile strength, flexural strength and melt flow rate performance indicators than the untreated nano-montmorillonite in Comparative Example 1 and the traditional process in Comparative Example 2, indicating that functionalized nanofillers and optimized processes have a significant effect on improving the performance of recycled ABS composite materials.

Claims

1. A composite material based on recycled ABS, characterized by: The invention comprises the following raw materials in parts by weight: 100 parts of waste ABS plastic, 2-5 parts of bifunctional macromolecular chain extender, 3-8 parts of functionalized nanofiller, 0.5-2 parts of composite deodorant, 0.3-1 parts of antioxidant, 0.1-0.5 parts of stearic acid, and 0.5-2 parts of ethylene glycol bis(3,4-dihydroxyphenyl borate); The bifunctional macromolecular chain extender is a mixture of adipic acid dihydrazide and ethylene glycol dimethacrylate in a mass ratio of 1:

1.

2. The composite material based on recycled ABS according to claim 1, characterized in that: The waste ABS plastic has a particle size of ≤1 mm and a moisture content of ≤0.5% after cleaning, and contains 15-20 wt% acrylonitrile, 5-10 wt% butadiene, and 70-75 wt% styrene; the composite deodorant is a mixture of β-cyclodextrin and activated carbon in a mass ratio of 2:1; and the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1.

3. The composite material based on recycled ABS according to claim 1, characterized in that: The functionalized nanofiller is specifically prepared in the following steps: A1. Dopamine hydrochloride was added to a Tris-HCl buffer solution to prepare a dopamine hydrochloride buffer solution; natural sodium montmorillonite was ground and passed through a 300-mesh sieve, then added to the dopamine hydrochloride buffer solution and stirred at 25°C for 24 hours; after the reaction, the mixture was transferred to a centrifuge tube, centrifuged for 10 minutes, and repeatedly washed with deionized water until the pH value of the washing solution reached 7. Finally, the washed montmorillonite was dried in a vacuum drying oven for 12 hours to obtain dopamine-modified montmorillonite; A2. Tetrabutyl titanate was added dropwise to an ethanol aqueous solution while stirring to form a uniform precursor solution; dopamine-modified montmorillonite was added to the above precursor solution, placed in a constant temperature water bath, and stirred at 60°C for 6 hours; after the reaction, the mixture was cooled to room temperature, centrifuged for 10 minutes, the supernatant was poured out, the precipitate was washed with anhydrous ethanol, and then the sample was placed in a vacuum drying oven and dried for 10 hours to obtain titanium dioxide-loaded montmorillonite; A3. Add silane coupling agent KH-570 to ethanol, then add deionized water, stir evenly, and let stand at room temperature for 30 minutes; add titanium dioxide-supported montmorillonite to the silane coupling agent KH-570 solution, transfer to a three-necked flask, and stir in a 90°C oil bath for 2 hours; after the reaction is completed, naturally cool to room temperature, centrifuge for 10 minutes to separate the modified montmorillonite, wash with ethanol, and finally place the sample in a vacuum drying oven for 8 hours to obtain KH-570-modified montmorillonite; A4. Place the KH-570-modified montmorillonite in a three-necked flask, add toluene as a solvent, and stir and disperse for 30 minutes; dissolve benzoyl peroxide in toluene to prepare an initiator solution, slowly drip it into the three-necked flask, stir in an 80°C oil bath for 30 minutes, add lactide monomer, continue heating to 120°C, and react under nitrogen protection for 4 hours; after the reaction, cool the mixture to room temperature, centrifuge for 10 minutes to remove the solvent, and wash with anhydrous ethanol. Place the product in a vacuum drying oven and dry it for 12 hours to obtain a functionalized nanofiller.

4. The recycled ABS composite material according to claim 3, characterized in that: In step A1, the pH of the Tris-HCl buffer solution is 8.5, the concentration is 0.1 mol / L, and the concentration of the dopamine hydrochloride buffer solution is 2 g / L; the amounts of natural sodium montmorillonite and dopamine hydrochloride buffer solution are 10 g and 150 mL respectively; the reaction stirring speed is 300 r / min, the centrifugal speed is 8000 r / min, and the drying temperature is 60°C.

5. The composite material based on recycled ABS according to claim 3, characterized in that: In step A2, ethanol and water are mixed in a volume ratio of 1:1; the amounts of tetrabutyl titanate, ethanol aqueous solution, and dopamine-modified montmorillonite are 3 g, 150 mL, and 10 g, respectively; the reaction stirring speed is 250 r / min, the centrifugal speed is 8000 r / min, the reaction is washed three times with anhydrous ethanol, and the drying temperature is 70°C.

6. The composite material based on recycled ABS according to claim 3, characterized in that: In step A3, the amounts of silane coupling agent KH-570, ethanol, deionized water, and titanium dioxide-loaded montmorillonite are 1.8 mL, 90 mL, 10 mL, and 8 g, respectively; the reaction stirring speed is 200 r / min, the centrifugal speed is 8000 r / min, the ethanol washing is performed three times, and the drying temperature is 80°C.

7. The composite material based on recycled ABS according to claim 3, characterized in that: In step A4, the amounts of KH-570 modified montmorillonite and toluene were 8 g and 80 mL respectively; the amounts of benzoyl peroxide and toluene in the initiator were 0.8 g and 7 mL respectively; and the amount of lactide monomer was 1.6 g; the centrifugal speed was 8000 r / min, the mixture was washed with anhydrous ethanol three times, and the drying temperature was 60°C.

8. A method for preparing a recycled ABS composite material, characterized in that: The specific steps include: S1. Pretreatment of waste ABS Crushing: Use a low-temperature crusher to crush the waste ABS into particles of 0.5~1mm; Cleaning: ultrasonic cleaning at 80℃ for 30min to remove impurities, centrifugal dehydration and vacuum drying at 70℃ for 6h; Characterization: Use FTIR to detect the absorption peak intensity of surface impurities to ensure the cleaning effect; S2, in-situ chain extension and nanocomposite blending Initial mixing: Mix the pretreated ABS with antioxidant and lubricant in a high-speed mixer at 60°C for 10 minutes to form a basic mixture; Plasma surface modification: Place the base mixture in a low-temperature plasma treatment device, using argon as the working gas, and treat for 3 to 5 minutes; Chain extension reaction: Add bifunctional macromolecular chain extender and dynamic covalent bond chain extender, transfer to the modified twin-screw extruder, set up a pressure-bearing closed cavity in the reaction section, and inject supercritical carbon dioxide at a pressure of 5-8 MPa through a high-pressure pump during the chain extension reaction. Set a temperature gradient and the material residence time is 3-5 minutes; Nanofiller and deodorant blending: Functionalized nanofiller and composite deodorant are injected simultaneously into the side feed port in the middle of the extruder, and nanoscale dispersion is achieved through the shear force of the screw; 3D gradient structure construction: The blended materials are injected into a mold with a gradient temperature field control. The mold temperature is gradually reduced by 5-10°C from the inlet to the outlet. At the same time, a pressure of 0.5-1 MPa is applied to orient the montmorillonite nanofillers and form a composite material body with a 3D gradient structure. S3, post-processing and performance optimization Microwave-assisted post-treatment: Place the green body in a special microwave drying device for 1-2 hours to achieve rapid drying and dynamic covalent bond rearrangement; Extrusion granulation: The pellets have a diameter of 2~3mm. After cooling, they are vacuum dried at 80℃ for 4h to remove residual moisture and unreacted small molecules to obtain recycled ABS products.

9. The method for preparing a recycled ABS composite material according to claim 8, wherein: In the step S1, the pulverization temperature is ≤30°C; and the ultrasonic power is 300W.

10. The method for preparing a composite material based on recycled ABS according to claim 8, characterized in that: In the step S2, the mixer speed is 800 r / min; the plasma treatment equipment power is 100~200 W; the screw extruder L / D is ≥30, the temperature gradient is: 180℃ / 195℃ / 210℃ / 220℃ / 215℃; the screw torque fluctuation is ≤±5Nm; in the step S3, the microwave power is 500~800 W.