ABS (Acrylonitrile Butadiene Styrene) material for electronic product shell and preparation method of ABS material

Abstract

The invention provides an ABS (Acrylonitrile Butadiene Styrene) material for an electronic product shell and a preparation method of the ABS material, and belongs to the field of ABS materials. The composite material is prepared from the following raw materials in parts by weight: 70 to 85 parts of ABS (Acrylonitrile Butadiene Styrene) resin, 5 to 15 parts of a structured toughening agent, 1 to 5 parts of butadiene functionalized graphite nanosheet filler, 2 to 8 parts of a hyperbranched dynamic cross-linking agent, 0.5 to 3 parts of a styrene-maleic anhydride copolymer, 0.1 to 1 part of diphenyl disulfide, 0.5 to 1.5 parts of a lubricating agent and 0.1 to 0.5 part of an antioxidant. Through precise component selection and structural design, a multi-mechanism collaborative system is constructed, and the strength, toughness and self-repairing performance of the ABS material are synchronously improved.

Description

Technical Field

[0001] This application relates to the field of ABS material technology, and in particular to an ABS material for electronic product casings and a method for preparing the same. Background Technology

[0002] Acrylonitrile-butadiene-styrene copolymer (ABS) is widely used in the manufacture of electronic product casings due to its excellent comprehensive mechanical properties, processing fluidity, and surface gloss. However, as electronic products develop towards high-end, thinner, and more durable products, traditional ABS materials face severe challenges in terms of performance, and the inherent balance between strength, toughness, and functionality is becoming increasingly prominent.

[0003] First, there is an inherent contradiction between strength and toughness in ABS materials. Its toughness primarily originates from the polybutadiene rubber phase dispersed in the SAN resin matrix, which absorbs impact energy by inducing crazes and shear bands. However, this toughening mechanism usually comes at the cost of sacrificing the material's rigidity, tensile strength, and heat distortion temperature. Increasing the rigidity of the SAN phase or adding rigid fillers to improve strength often leads to a sharp decrease in toughness, making the material brittle. Therefore, how to significantly improve the material's strength while maintaining or even enhancing its toughness has long been a technical bottleneck. Second, traditional ABS, as a thermoplastic material, lacks inherent damage repair capabilities. During daily use, the casing is prone to microcracks due to scratches and impacts. These damages gradually expand, affecting not only the appearance but also becoming stress concentration points, ultimately leading to component failure and shortening product lifespan. Imparting self-healing capabilities to automatically repair microscopic damage is an ideal way to improve the reliability and durability of electronic products, but this poses a significant challenge for conventional ABS systems. Therefore, developing an innovative ABS composite material that fundamentally resolves the contradiction between strength and toughness while simultaneously integrating efficient self-healing capabilities has become an inevitable technological direction to meet the demanding performance requirements of next-generation high-end electronic product casings. Summary of the Invention

[0004] This application provides an ABS material for electronic product casings and a method for preparing the same, in order to solve the following technical problem: how to simultaneously improve the strength, toughness, and self-healing properties of ABS materials.

[0005] In a first aspect, embodiments of this application provide an ABS composite material for electronic product housings, wherein the composite material, by weight, is composed of the following raw materials: ABS resin: 70-85 parts, structural toughening agent: 5-15 parts, butadiene-functionalized graphite nanosheet filler: 1-5 parts, hyperbranched dynamic crosslinking agent: 2-8 parts, styrene-maleic anhydride copolymer: 0.5-3 parts, diphenyl disulfide: 0.1-1 parts, lubricant: 0.5-1.5 parts, antioxidant: 0.1-0.5 parts; The structured toughening agent is a core-shell structured polybutadiene rubber particle, wherein the core layer of the core-shell structured polybutadiene rubber particle is polybutadiene rubber, the transition layer is a butadiene-styrene-acrylonitrile terpolymer, and the shell layer is a styrene-acrylonitrile copolymer rich in epoxy functional groups. The hyperbranched dynamic crosslinking agent is a hyperbranched polyester with end groups simultaneously modified with furan groups and thiol groups.

[0006] Optionally, the preparation method of the structured toughening agent includes the following steps: S101. Add water to polybutadiene rubber latex, and then keep it at 65-75℃ for 30-60 minutes to obtain seed latex solution. S102. Add an emulsifier and a first initiator to the seed latex, then add a first mixed monomer composed of butadiene, styrene and acrylonitrile dropwise, and continue the reaction at 70-80°C for 3-6 hours to obtain an intermediate latex. S103. Adjust the temperature of the intermediate latex to 70-85°C, then add dropwise a second mixed monomer composed of styrene, acrylonitrile and glycidyl methacrylate, and add a second initiator. After the dropwise addition is complete, raise the temperature to 80-90°C and mature for 2-4 hours. After coagulation, washing and drying, the structured toughening agent is obtained.

[0007] Optionally, the solid content of the seed latex is 10-25%; The mass ratio of butadiene, styrene and acrylonitrile is (40-60):(30-50):(10-20); The emulsifier is a complex of potassium oleate and disproportionated rosin soap, wherein the mass ratio of potassium oleate to disproportionated rosin soap is 1:(0.5-2), and the mass of the emulsifier is 0.4-1.0% of the total mass of the first mixed monomers. The first initiator is potassium persulfate, and the mass of the first initiator is 0.2% to 0.5% of the total mass of the first mixed monomers. The mass ratio of styrene, acrylonitrile and glycidyl methacrylate is (70-85):(15-25):(5-10); The second initiator is potassium persulfate, and the mass of the second initiator is 0.1 to 0.3% of the total mass of the second mixed monomers.

[0008] Optionally, the preparation method of the butadiene-functionalized graphite nanosheet filler includes the following steps: S201. Add graphite nanosheets to a mixed acid solution and stir the reaction at 30-50°C for 4-12 hours. After post-treatment, obtain graphite oxide nanosheets. S202. The graphene oxide nanosheets are dispersed in thionyl chloride, and then N,N-dimethylformamide is added. The mixture is refluxed at 60-80°C for 12-24 hours. Excess thionyl chloride is removed by vacuum distillation to obtain acyl chloride graphene nanosheets with acyl chloride groups on the surface. S203. Under an inert atmosphere, the acyl chloride graphite nanosheets, the third initiator, the catalyst and the solvent are mixed and activated at 50-70°C for 0.5-2 hours. Then, butadiene monomer is added and surface-initiated atom transfer radical polymerization is carried out at 60-80°C for 6-24 hours. After post-treatment, the butadiene functionalized graphite nanosheet filler is obtained.

[0009] Optionally, the volume of the N,N-dimethylformamide is 0.5% to 5% of the volume of the thionyl chloride; The third initiator is 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide, and the molar ratio of the butadiene monomer to the third initiator is (50-300):1; The catalyst is a complex of cuprous bromide and pentamethyldiethylenetriamine, wherein the molar ratio of pentamethyldiethylenetriamine to cuprous bromide is (1.5-3):1, and the molar ratio of cuprous bromide to the third initiator is (1-2):1.

[0010] Optionally, the preparation method of the hyperbranched dynamic crosslinking agent includes the following steps: S301. Mix pyromellitic anhydride, trimethylolpropane and p-toluenesulfonic acid, and then carry out melt polycondensation reaction at 120-160℃ for 4-10h to obtain hyperbranched polyester with hydroxyl end groups. S302. The hyperbranched polyester is dissolved in an organic solvent, and then 2-furan carboxylic acid, mercaptoacetic acid, 4-dimethylaminopyridine and dicyclohexylcarbodiimide are added in sequence. The mixture is reacted at 40-80°C for 12-36 hours. After post-treatment, the hyperbranched polyester with end groups simultaneously modified with furan groups and thiol groups is obtained.

[0011] Optionally, the molar ratio of the pyromellitic anhydride to the trimethylolpropane is 1:(1.05-1.3); The mass of the p-toluenesulfonic acid is 0.5% to 1.5% of the total mass of the pyromellitic anhydride and the trimethylolpropane. The molar ratio of the terminal hydroxyl groups of the hyperbranched polyester, the 2-furan carboxylic acid, and the mercaptoacetic acid is 1:(0.4-0.6):(0.4-0.6). The molar ratio of the total carboxyl groups of the dicyclohexylcarbodiimide to that of the 2-furan carboxylic acid and the mercaptoacetic acid is (1-1.2):1; The molar ratio of the total carboxyl groups of the 4-dimethylaminopyridine to the 2-furan carboxylic acid and the mercaptoacetic acid is (0.05-0.15):1.

[0012] Optionally, the lubricant is zinc stearate; The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0013] Secondly, embodiments of this application provide a method for preparing ABS composite material for electronic product housings as described in any one of the first aspects, the method comprising the following steps: S1. The ABS resin, the structured toughening agent, the butadiene-functionalized graphite nanosheet filler, the styrene-maleic anhydride copolymer, the lubricant and the antioxidant are premixed to obtain a premixed material. S2. The premixed material is added to the twin-screw extruder through the main feed port. At the same time, the hyperbranched dynamic crosslinking agent is mixed with diphenyl disulfide and injected into the rear section of the melting section of the twin-screw extruder through the side feed port. After melt blending, extrusion, cooling and pelletizing, the ABS composite material is obtained.

[0014] Optionally, the melt blending temperature is 190–200°C; The screw speed of the twin-screw extruder is 250~350 r / min, and the side feed rate of the hyperbranched dynamic crosslinking agent and diphenyl disulfide is 0.8~1.2 g / min.

[0015] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides an ABS composite material for electronic product housings. Through precise component selection and structural design, a multi-mechanism synergistic system is constructed to simultaneously improve the strength, toughness, and self-healing properties of ABS materials.

[0016] In terms of strength enhancement, ABS resin serves as the continuous phase matrix, with its styrene-acrylonitrile copolymer hard segments providing basic rigidity and a load-bearing framework. Butadiene-functionalized graphite nanosheets form a rigidity-enhancing network due to their high modulus properties, and the butadiene segments grafted on the surface form segment entanglements with the polybutadiene phase in the ABS matrix, strengthening the interfacial bonding between the filler and the matrix and efficiently transferring stress. The anhydride groups of the styrene-maleic anhydride copolymer react chemically with the epoxy groups of the structured toughening agent shell to construct a strong covalent bond interface, eliminating interfacial defects and further improving the overall structural density and load-bearing capacity.

[0017] The core of toughness optimization lies in the core-shell design of the structured toughening agent: the polybutadiene rubber core layer, as a flexible unit, can initiate and terminate crazing through large deformation, efficiently absorbing impact energy; the butadiene-styrene-acrylonitrile transition layer achieves a smooth modulus transition, avoids stress concentration, and promotes uniform energy dissipation; the strong interface formed by the shell layer rich in epoxy functional groups and the compatibilizer ensures that stress is efficiently transferred from the matrix to the rubber core, giving full play to the toughening effect.

[0018] Self-healing is achieved through a dual dynamic covalent network: the furan and thiol groups at the end of the hyperbranched dynamic crosslinking agent can form a reversible Michael addition network, and the disulfide bond of diphenyl disulfide can undergo a reversible exchange reaction. When the material is damaged, the dynamic bond in the dynamic system constructed by the two will preferentially break and dissipate energy. Subsequently, it can be reorganized under thermal or static conditions to achieve damage repair. At the same time, the flexibility of the dynamic network can also help improve the toughness of the material, ultimately forming a synergistic mechanism of "rigid load-flexible dissipation-dynamic repair", which simultaneously optimizes the three core properties. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic flowchart illustrating a method for preparing ABS material for electronic product casings, as provided in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] This application provides an ABS composite material for electronic product casings. By weight, the composite material is composed of the following raw materials: ABS resin: 70-85 parts; structural toughening agent: 5-15 parts; butadiene-functionalized graphite nanosheet filler: 1-5 parts; hyperbranched dynamic crosslinking agent: 2-8 parts; styrene-maleic anhydride copolymer: 0.5-3 parts; diphenyl disulfide: 0.1-1 parts; lubricant: 0.5-1.5 parts; antioxidant: 0.1-0.5 parts. The structured toughening agent is a core-shell structured polybutadiene rubber particle, wherein the core layer of the core-shell structured polybutadiene rubber particle is polybutadiene rubber, the transition layer is a butadiene-styrene-acrylonitrile terpolymer, and the shell layer is a styrene-acrylonitrile copolymer rich in epoxy functional groups. The hyperbranched dynamic crosslinking agent is a hyperbranched polyester with end groups simultaneously modified with furan groups and thiol groups.

[0024] It should be noted that 'rich in epoxy functional groups' means that the content of epoxy groups provided by glycidyl methacrylate in the shell copolymer is 5~10 wt%; 'simultaneous end group modification' means that 40%~60% of the terminal hydroxyl groups of the hyperbranched polyester are modified by furan groups, and another 40%~60% are modified by thiol groups.

[0025] The ABS composite material system in this application, through meticulous molecular and structural design, constructs a high-performance polymer composite material with multi-level and multi-mechanism synergistic effects. Its superior macroscopic properties are rooted in the well-defined interactions between the components at the molecular and nanoscale, which complement and reinforce each other, forming an organic whole.

[0026] ABS resin: The molecular structure of ABS resin consists of hard segments of styrene-acrylonitrile (SAN) copolymer and soft segments of polybutadiene (PB) rubber. Its functionality is based on the theory of synergistic effects of rigid and flexible segments in polymer chains. In the SAN hard segments, the conjugated structure of the benzene rings endows the molecular chain with rigidity (glass transition temperature 100℃), and the polar interaction of the cyano groups (dipole-dipole forces) enhances the interchain cohesion, providing the material with basic strength, rigidity, and processing fluidity. The PB rubber soft segments (glass transition temperature -80℃) dispersed in the SAN continuous phase have flexible carbon-carbon single bonds that can rotate freely, absorbing a small amount of impact energy through segment slip, laying the foundation for the material's basic toughness. Through the molecular division of labor of "hard segment bearing load - soft segment consuming energy," the two form the basic mechanical framework of the matrix. At the same time, the solubility parameters of the SAN segments match most components in the system, providing a thermodynamic basis for the compatibility of subsequent functional components.

[0027] Structured toughening agents: The core-shell structure design of structured toughening agents relies on the modulus transition theory and the interfacial chemical bonding theory to achieve toughening function. The core layer, composed of long-chain flexible molecules (high double bond content) of PB rubber, can undergo large-scale chain segment deformation and entanglement slip under impact loads. Through the crazing initiation-termination theory, it actively initiates numerous microcrazings and prevents them from developing into cracks, serving as the main energy dissipation unit. The transition layer, composed of butadiene-styrene-acrylonitrile (ABS) terpolymer, ensures a smooth transition of the material modulus from the rubber core (0.1–0.3 GPa) to the plastic shell (2–3 GPa). According to the stress concentration mitigation theory, it avoids interfacial stress caused by abrupt modulus changes. Force concentration ensures uniform diffusion of silver streaks; the epoxy functional groups (-COC-) rich in the shell can undergo an epoxy-anhydride ring-opening reaction with the anhydride groups (-CO-O-CO-) of styrene-maleic anhydride copolymer (SMA) to form stable ester covalent bonds, thus constructing a "chemical anchoring" interface between the rubber particles and the ABS matrix. According to the theory of interfacial stress transfer, this strong interface can achieve efficient transfer of load from the rigid matrix to the flexible rubber particles, forcing the rubber core to fully deform and dissipate energy, while inhibiting interfacial debonding and stress whitening phenomena.

[0028] Butadiene-functionalized graphite nanosheets: The functionality of this filler stems from the synergy of chain segment entanglement theory, π-π conjugation interaction theory, and nanoparticle enhancement theory. The layered structure of the graphite nanosheets is composed of sp... 2 Composed of hybrid carbon atoms, the PB segments grafted onto the surface of the graphite nanosheets have the same chemical structure as the soft PB rubber segments in the ABS matrix. According to the chain entanglement theory, the two can undergo molecular chain interpenetration and entanglement, forming physical cross-linking points. Simultaneously, there is a π-π electron cloud overlap between the benzene ring conjugated system of the graphite sheets and the benzene rings of the SAN segments and the unsaturated double bonds of the PB segments in the ABS resin (binding energy 10–30 kJ / mol), far exceeding ordinary van der Waals forces (0.1–1 kJ / mol). The superposition of these two strong physical interactions creates an "entanglement-conjugation" dual interface between the filler and the matrix, solving the problems of poor dispersibility and weak interfacial bonding in traditional nanofillers. Furthermore, the high modulus (1 TPa) and high aspect ratio of the graphite nanosheets, according to the rigid particle reinforcement theory, can form a "rigid support network" in the matrix, improving the tensile strength, flexural modulus, and barrier properties of the material, while also improving thermal stability through the sheet-like thermal conduction pathway.

[0029] Hyperbranched dynamic crosslinking agent and diphenyl disulfide: The two work together to construct a dual dynamic network, which is based on the dynamic covalent bond theory (the “breakage-recombination” property of reversible chemical bonds). The hyperbranched polyester backbone of the hyperbranched dynamic crosslinking agent has a multi-terminal structure (high functionality). Its end-modified furan groups can undergo a reversible Diels-Alder addition reaction with the maleimide groups of the styrene-maleic anhydride copolymer (SMA) in the system (or unsaturated double bonds contained in the matrix / toughening agent), achieving bond breaking and recombination under thermal / mechanical stimulation to form the first-level dynamic crosslinking network. Its end-modified thiol groups (-SH) can undergo a reversible thiol-disulfide bond exchange reaction with the disulfide bonds of diphenyl disulfide (Ph-SS-Ph), and can also form dynamic thioether bonds with the epoxy functional groups of the structured toughening agent shell, jointly constructing the second-level dynamic crosslinking network. Diphenyl disulfide, as a dynamic bond exchange medium, can promote the uniform distribution and rapid exchange of disulfide bonds within the system, strengthening the synergistic effect of the two dynamic networks. The two dynamic bond networks interweave and synergistically act to form a stable and repairable dynamic crosslinking system. According to the sacrificial bond theory, the bond energies of these two dynamic covalent bonds (Michael addition bond 80-120 kJ / mol, disulfide bond 250-300 kJ / mol) are both lower than those of the C-C main valence bond (348 kJ / mol). Under impact or tensile loads, the dynamic bonds can preferentially break to dissipate a large amount of energy and avoid material failure caused by main chain breakage. Under thermal or static conditions, the broken dynamic bonds can be reassembled, giving the material self-healing ability and reprocessability, achieving the dual function of "toughness enhancement - damage repair".

[0030] Styrene-maleic anhydride copolymer (SMA): The functionality of SMA relies on the theories of solubility parameter matching and interfacial coupling. The solubility parameters of its styrene segments are highly similar to those of the SAN segments in the ABS matrix. According to thermodynamic compatibility theory, the two can achieve molecular-level compatibility, ensuring uniform dispersion of SMA within the matrix. The anhydride groups in its molecular chain exhibit high reactivity. Besides undergoing ring-opening reactions with the epoxy groups in the structured toughening agent shell, they can also undergo esterification reactions with the hydroxyl and carboxyl groups remaining on the surface of butadiene-functionalized graphite nanosheets, or form hydrogen bonds with the hydroxyl groups of the hyperbranched crosslinking agent. Through a molecular design of "one-end compatibility, one-end reaction," SMA constructs "chemical bridges" between components with weak interfacial interactions, such as the ABS matrix, toughening agent, and nanofillers. Based on the theory of enhanced interfacial adhesion, this significantly improves the interfacial adhesion strength of the multiphase system, eliminates interfacial defects, and lays the foundation for efficient stress transfer and synergistic function of each component.

[0031] Lubricants and antioxidants: The role of lubricants (zinc stearate) is based on the interfacial lubrication theory. The long-chain alkyl (non-polar) molecules in their molecular structure can insert between polymer chains, reducing the inter-chain friction coefficient. At the same time, they migrate to the material surface during processing to form a lubricating film, reducing the adhesion of the melt to the equipment and improving processing fluidity. Antioxidants (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) are based on the free radical capture theory. The phenolic hydroxyl groups in their molecules can capture polymer free radicals generated during processing or use, terminating the free radical chain reaction through proton transfer, inhibiting the oxidative degradation and cross-linking aging of polymer chains, and ensuring the long-term stability of the material's molecular structure.

[0032] More importantly, the synergistic effect among the components in the ABS composite system constitutes the core of the performance leap.

[0033] Synergistic effect of rigidity and flexibility and stress transfer: The SAN hard segments of the ABS matrix, the rigid framework of graphite nanosheets, and the dynamic cross-linking network constitute a "rigid load-bearing system," while the PB soft core of the structured toughening agent and the PB soft segments in ABS constitute a "flexible dissipation system." Through the chemical bridging bonds constructed by SMA and the transition layer of the toughening agent, according to the stress transfer theory, external loads can be efficiently and smoothly transferred from the rigid system to the flexible system: the rigid system provides load-bearing capacity to maintain the material's shape and strength, while the flexible system dissipates energy through chain segment deformation, crazing, and other mechanisms, achieving a unified mechanical property of "high strength and high toughness," avoiding the contradiction of "the trade-off between rigidity and toughness" in traditional materials.

[0034] Interface synergy and dispersion synergy: The "chemically bonded interfaces" (toughening agent-matrix, SMA-filler) and "strong physical interaction interfaces" (filler-matrix π-π interaction, chain segment entanglement) formed in the system jointly construct a defect-free continuous interface network based on the multiphase interface strengthening theory. On the one hand, chemical bonding and strong physical interaction inhibit filler agglomeration and rubber particle migration, ensuring that each functional component is uniformly dispersed in the matrix. On the other hand, the continuous interface network enables stress to be transferred between the multiphases without loss, avoiding interface debonding or stress concentration at defects, and simultaneously improving the reinforcement efficiency and toughening effect of the material, achieving a positive synergy of "dispersion uniformity-interface strength-mechanical properties".

[0035] Synergistic Dynamic-Static Network and Energy Dissipation: The static covalent backbone and dynamic cross-linked network of the ABS matrix form a "static-dynamic dual-network structure." Based on the multi-mechanism energy dissipation theory, the two work together to achieve efficient energy dissipation: When the material is subjected to external force, the reversible bonds (Michael addition bonds, disulfide bonds) in the dynamic network break preferentially as "sacrificial bonds," dissipating a large amount of energy. If the external force continues to increase, the structured toughening agent induces crazes and entanglement slippage of PB segments, further dissipating energy. Finally, the static backbone and graphite filler bear the remaining load, preventing material fracture. This "multi-level energy dissipation" mechanism enables the material to dissipate energy through corresponding mechanisms when subjected to loads of different intensities. At the same time, the reorganization ability of the dynamic bonds endows the material with self-healing properties, achieving a synergistic improvement in "impact resistance, self-healing, and durability."

[0036] Processing-Performance Synergy: The system's component design and processing technology are highly matched. Based on the theory of polymer processing rheology, the compatibility of SMA and the lubrication of the lubricant reduce the melt viscosity, ensuring good fluidity of the material at processing temperatures of 190-200℃. The hyperbranched dynamic crosslinking agent is injected through a side-feeding method, avoiding the sudden increase in melt viscosity caused by premature crosslinking and ensuring smooth processing. The dynamic network and interfacial chemical bonds formed during processing are transformed into excellent mechanical properties and self-healing properties after the material is formed, achieving a synergistic unity of "processing fluidity-forming quality-final performance" and meeting the dual requirements of material processing precision and performance for electronic product casings.

[0037] In summary, this material system, by constructing a multi-scale synergistic system based on strong interfacial chemical bonding, using structural toughening and nanofiller reinforcement, and featuring a dynamic reversible covalent network, achieves efficient energy dissipation and uniform stress distribution at the molecular level. This results in a comprehensive macroscopic balance of high strength, ultra-high toughness, self-healing properties, and good processability, perfectly meeting the stringent performance requirements of high-end electronic product casings.

[0038] In some embodiments, the method for preparing the structured toughening agent includes the following steps: S101. Add water to polybutadiene rubber latex, and then keep it at 65-75℃ for 30-60 minutes to obtain seed latex solution. S102. Add an emulsifier and a first initiator to the seed latex, then add a first mixed monomer composed of butadiene, styrene and acrylonitrile dropwise, and continue the reaction at 70-80°C for 3-6 hours to obtain an intermediate latex. S103. Adjust the temperature of the intermediate latex to 70-85°C, then add dropwise a second mixed monomer composed of styrene, acrylonitrile and glycidyl methacrylate, and add a second initiator. After the dropwise addition is complete, raise the temperature to 80-90°C and mature for 2-4 hours. After coagulation, washing and drying, the structured toughening agent is obtained.

[0039] In some embodiments, the solid content of the seed latex is 10-25%; The mass ratio of butadiene, styrene and acrylonitrile is (40-60):(30-50):(10-20); The emulsifier is a complex of potassium oleate and disproportionated rosin soap, wherein the mass ratio of potassium oleate to disproportionated rosin soap is 1:(0.5-2), and the mass of the emulsifier is 0.4-1.0% of the total mass of the first mixed monomers. The first initiator is potassium persulfate, and the mass of the first initiator is 0.2% to 0.5% of the total mass of the first mixed monomers. The mass ratio of styrene, acrylonitrile and glycidyl methacrylate is (70-85):(15-25):(5-10); The second initiator is potassium persulfate, and the mass of the second initiator is 0.1 to 0.3% of the total mass of the second mixed monomers.

[0040] It should be noted that the structured toughening agent is prepared using a multi-step seed emulsion polymerization method. The overall process follows the "particle nucleation-layer-by-layer growth" principle of emulsion polymerization. By precisely controlling the reaction conditions at each stage, the orderly construction from rubber seeds to core-shell structures is achieved. The role and principle of each step and parameter are as follows: Step S101 is the pretreatment stage of the seed latex solution. Water is added to the polybutadiene rubber latex and the mixture is kept at 65–75°C for 30–60 minutes. The core function is to adjust the commercial rubber latex into a seed system suitable for subsequent graft polymerization. The seed latex solution with a solid content of 10–25% formed after dilution with water provides sufficient space for subsequent monomer diffusion and polymerization, while ensuring the dispersion stability of latex particles and preventing particle aggregation. The holding temperature of 65–75°C allows the latex particles to reach a thermodynamically stable state, laying a uniform reaction base for subsequent graft polymerization.

[0041] Step S102 is the construction stage of the transition layer. An emulsifier and a first initiator are added to the seed latex, followed by the dropwise addition of a butadiene-styrene-acrylonitrile first mixed monomer. The reaction is carried out at 70–80°C for 3–6 hours to obtain an intermediate latex. This step relies on the "grafting onto the surface of rubber particles" principle of latex polymerization to grow a modulus transition layer on the surface of the rubber seed. The mass ratio of butadiene, styrene, and acrylonitrile (40-60):(30-50):(10-20) allows the transition layer polymer to possess both compatibility with the rubber core and modulus for transitioning to the plastic shell. The high butadiene content ensures elastic bonding, while the introduction of styrene and acrylonitrile gradually increases the modulus. The emulsifier, a mixture of potassium oleate and disproportionated rosin soap at a ratio of 1:(0.5-2), used at 0.4-1.0% of the total mass of the first mixed monomers, synergistically enhances the mechanical and chemical stability of the emulsion, stabilizing the newly formed polymer latex particles. The potassium persulfate initiator, accounting for 0.2-0.5% of the total mass of the first mixed monomers, can continuously decompose in the aqueous phase to generate free radicals, driving the monomers to polymerize stably on the surface of the particles and controlling the polymerization rate and product molecular weight. The reaction temperature of 70-80℃ and the reaction time of 3-6h are adapted to the polymerization kinetics of the ternary monomers, ensuring that the transition layer is uniformly coated on the surface of the seed particles.

[0042] Step S103 is the grafting stage of the reactive shell. The intermediate latex is adjusted to 70–85°C, and then a second mixed monomer of styrene-acrylonitrile-glycidyl methacrylate is added dropwise along with a second initiator. After the addition, the temperature is raised to 80–90°C and cured for 2–4 hours. The target toughening agent is obtained after post-treatment. This step utilizes the principle of "shell monomer directional polymerization" to construct a reactive hard shell outside the transition layer. The mass ratio of styrene, acrylonitrile, and glycidyl methacrylate (70–85):(15–25):(5–10) ensures that the shell layer is a SAN plastic phase compatible with the ABS matrix, while also introducing sufficient and uniform epoxy reaction sites through 5–10% glycidyl methacrylate. The potassium persulfate initiator, comprising 0.1–0.3% of the total mass of the second mixed monomers, adapts to the polymerization environment on the particle surface, enabling precise grafting of the shell monomers and avoiding the formation of free homopolymer particles. The dropping temperature of 70–85°C, the curing temperature of 80–90°C, and the curing time of 2–4 hours ensure complete polymerization of the shell monomers while maintaining the structural integrity of the epoxy groups, providing an active basis for subsequent interfacial chemical bonding.

[0043] In some embodiments, the preparation method of the butadiene-functionalized graphite nanosheet filler includes the following steps: S201. Add graphite nanosheets to a mixed acid solution and stir the reaction at 30-50°C for 4-12 hours. After post-treatment, obtain graphite oxide nanosheets. S202. The graphene oxide nanosheets are dispersed in thionyl chloride, and then N,N-dimethylformamide is added. The mixture is refluxed at 60-80°C for 12-24 hours. Excess thionyl chloride is removed by vacuum distillation to obtain acyl chloride graphene nanosheets with acyl chloride groups on the surface. S203. Under an inert atmosphere, the acyl chloride graphite nanosheets, the third initiator, the catalyst and the solvent are mixed and activated at 50-70°C for 0.5-2 hours. Then, butadiene monomer is added and surface-initiated atom transfer radical polymerization is carried out at 60-80°C for 6-24 hours. After post-treatment, the butadiene functionalized graphite nanosheet filler is obtained.

[0044] In some embodiments, the volume of the N,N-dimethylformamide is 0.5% to 5% of the volume of the thionyl chloride; The third initiator is 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide, and the molar ratio of the butadiene monomer to the third initiator is (50-300):1; The catalyst is a complex of cuprous bromide and pentamethyldiethylenetriamine, wherein the molar ratio of pentamethyldiethylenetriamine to cuprous bromide is (1.5-3):1, and the molar ratio of cuprous bromide to the third initiator is (1-2):1.

[0045] It should be noted that butadiene-functionalized graphite nanosheets were prepared via a three-step method of "oxidative activation-acyl chloride enhancement-ATRP grafting". This method relies on surface chemical modification and controlled free radical polymerization to achieve interfacial compatibility between the graphite nanosheets and the polymer matrix. The role and principle of each step and parameter are as follows: Step S201 is the oxidation activation stage, in which graphite nanosheets are placed in a mixed acid solution and stirred at 30–50°C for 4–12 hours. After post-treatment, oxidized graphite nanosheets are obtained. This step is based on the principle of "strong acid oxidation etching," introducing oxygen-containing active sites such as carboxyl and hydroxyl groups at the edges and defects of the graphite sheets. The reaction temperature of 30–50°C and the reaction time of 4–12 hours allow for controlled oxidation of the graphite sheets, introducing sufficient active functional groups as anchor points for subsequent reactions while maintaining the basic structural integrity of the graphite sheets, preserving their inherent rigidity and thermal conductivity.

[0046] Step S202 is the acyl chloride enhancement stage. Graphite oxide nanosheets are dispersed in thionyl chloride and N,N-dimethylformamide is added. The mixture is refluxed at 60–80°C for 12–24 hours, and then distilled under reduced pressure to obtain acyl chloride graphite nanosheets. This step follows the principle of "carboxyl acyl chloride modification," converting surface oxygen-containing groups into highly reactive acyl chloride groups. N,N-dimethylformamide, at 0.5–5% by volume of thionyl chloride, acts as a catalyst, significantly improving the reaction efficiency between thionyl chloride and carboxyl groups, ensuring complete conversion of the carboxyl groups. The reflux temperature of 60–80°C and the reaction time of 12–24 hours provide sufficient energy and reaction time for the acyl chloride reaction, guaranteeing the complete conversion of the active groups.

[0047] Step S203 is the ATRP grafting stage. Under an inert atmosphere, acyl chloride graphite nanosheets, a third initiator, a catalyst, and a solvent are mixed and activated at 50–70°C for 0.5–2 hours. Then, butadiene monomer is added, and surface-initiated atom transfer radical polymerization is carried out at 60–80°C for 6–24 hours. After post-treatment, the target filler is obtained. This step relies on the principle of "surface-initiated living polymerization" to controllably graft polybutadiene segments onto the filler surface. Among them, 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide is selected as the third initiator, which can be anchored to the hydroxyl groups on the filler surface through the siloxane end; the molar ratio of butadiene monomer to the third initiator (50-300):1 can flexibly control the degree of polymerization of the grafted chain and achieve precise customization of the grafted chain length; the complexing catalyst of cuprous bromide and pentamethyldiethylenetriamine in a molar ratio of 1.5-3:1, and the molar ratio of copper salt to initiator in a molar ratio of 1-2:1 can provide highly active and controllable catalytic centers for ATRP polymerization, ensuring that the molecular weight distribution of the grafted chain is narrow and the chain length is uniform; the activation temperature of 50-70℃ and the activation time of 0.5-2h can complete the anchoring of the initiator and the pre-assembly of the catalytic system; the polymerization temperature of 60-80℃ and the polymerization time of 6-24h are adapted to the ATRP polymerization kinetics of butadiene monomer to achieve uniform grafting of chain segments.

[0048] In some embodiments, the preparation method of the hyperbranched dynamic crosslinking agent includes the following steps: S301. Mix pyromellitic anhydride, trimethylolpropane and p-toluenesulfonic acid, and then carry out melt polycondensation reaction at 120-160℃ for 4-10h to obtain hyperbranched polyester with hydroxyl end groups. S302. The hyperbranched polyester is dissolved in an organic solvent, and then 2-furan carboxylic acid, mercaptoacetic acid, 4-dimethylaminopyridine and dicyclohexylcarbodiimide are added in sequence. The mixture is reacted at 40-80°C for 12-36 hours. After post-treatment, the hyperbranched polyester with end groups simultaneously modified with furan groups and thiol groups is obtained.

[0049] In some embodiments, the molar ratio of the pyromellitic anhydride to the trimethylolpropane is 1:(1.05-1.3); The mass of the p-toluenesulfonic acid is 0.5% to 1.5% of the total mass of the pyromellitic anhydride and the trimethylolpropane. The molar ratio of the terminal hydroxyl groups of the hyperbranched polyester, the 2-furan carboxylic acid, and the mercaptoacetic acid is 1:(0.4-0.6):(0.4-0.6). The molar ratio of the total carboxyl groups of the dicyclohexylcarbodiimide to that of the 2-furan carboxylic acid and the mercaptoacetic acid is (1-1.2):1; The molar ratio of the total carboxyl groups of the 4-dimethylaminopyridine to the 2-furan carboxylic acid and the mercaptoacetic acid is (0.05-0.15):1.

[0050] The hyperbranched dynamic crosslinking agent is prepared using a two-step method of "melt polycondensation into a framework - end-group functionalization modification". Following the principle of stepwise polycondensation and esterification modification, it achieves precise grafting of dual dynamic groups. The role and principle of each step and parameter are as follows: Step S301 is the synthesis stage of the hyperbranched polyester backbone. Pyromellitic anhydride, trimethylolpropane, and p-toluenesulfonic acid are mixed and melt-polymerized at 120–160°C for 4–10 hours to obtain a hydroxyl-terminated hyperbranched polyester. This step is based on the principle of "multi-component monomer melt polycondensation" to construct a highly branched polymer backbone with hydroxyl-terminated groups. Specifically, the molar ratio of pyromellitic anhydride to trimethylolpropane is 1:(1.05–1.3), with a slight excess of trimethylolpropane, ensuring complete polycondensation and hydroxyl-terminated products, providing reaction sites for subsequent functionalization. P-Toluenesulfonic acid, accounting for 0.5–1.5% of the total monomer mass, efficiently catalyzes the esterification polycondensation reaction, accelerating the polymerization process. The melting temperature of 120–160°C ensures the reactants form a homogeneous melt, guaranteeing the uniformity of the polymerization reaction. The reaction time of 4–10 hours promotes high conversion rates, forming a hyperbranched polymer with the target molecular weight.

[0051] Step S302 is the end-group dual functionalization stage. After dissolving the hyperbranched polyester, 2-furan carboxylic acid, mercaptoacetic acid, 4-dimethylaminopyridine, and dicyclohexylcarbodiimide are added sequentially, and the reaction is carried out at 40–80°C for 12–36 hours to obtain the target crosslinking agent. This step relies on the principle of "esterification coupling," grafting furan and thiol dual dynamic groups onto the hydroxyl groups at the backbone end. The molar ratio of hyperbranched polyester terminal hydroxyl groups, 2-furan carboxylic acid, and mercaptoacetic acid (1:(0.4–0.6):(0.4–0.6)) enables balanced grafting of the two dynamic groups, allowing each hyperbranched molecule to carry approximately the same number of furan and thiol groups, laying the foundation for constructing a uniform dual-dynamic network. The molar ratio of dicyclohexylcarbodiimide to total carboxyl groups (1–1.2:1) allows for efficient forward esterification by using equimolar or slightly excess dehydrating agents, ensuring complete reaction of the carboxylic acid feedstock. The molar ratio of 4-dimethylaminopyridine to total carboxyl groups (0.05–0.15:1) enables efficient acylation catalysis at low dosages, balancing catalytic efficiency and purification convenience. A reaction temperature of 40–80°C and a reaction time of 12–36 h ensure the completeness of the esterification reaction while preventing thermal decomposition of furan groups at high temperatures, thus ensuring the structural stability of the dual-dynamic groups.

[0052] In some embodiments, the lubricant is zinc stearate; The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

[0053] Figure 1 This is a schematic flowchart illustrating a method for preparing ABS material for electronic product casings, as provided in an embodiment of this application.

[0054] Based on a general inventive concept, such as Figure 1 As shown in the figure, this application provides a method for preparing ABS composite material for electronic product housings as described in any one of the above-mentioned embodiments, the method comprising the following steps: S1. The ABS resin, the structured toughening agent, the butadiene-functionalized graphite nanosheet filler, the styrene-maleic anhydride copolymer, the lubricant and the antioxidant are premixed to obtain a premixed material. S2. The premixed material is added to the twin-screw extruder through the main feed port. At the same time, the hyperbranched dynamic crosslinking agent is mixed with diphenyl disulfide and injected into the rear section of the melting section of the twin-screw extruder through the side feed port. After melt blending, extrusion, cooling and pelletizing, the ABS composite material is obtained.

[0055] In some embodiments, the melt blending temperature is 190–200°C; The screw speed of the twin-screw extruder is 250~350 r / min, and the side feed rate of the hyperbranched dynamic crosslinking agent and diphenyl disulfide is 0.8~1.2 g / min.

[0056] It should be noted that the premixing step follows the theory of polymer dry mixing and predispersion. Mechanical stirring breaks up the initial agglomeration of non-crosslinked raw materials such as ABS resin, structured toughening agent, and butadiene-functionalized graphite nanosheets, ensuring that the solid components adhere uniformly to the resin surface. Simultaneously, it promotes the initial wetting of the styrene-maleic anhydride copolymer with the ABS matrix, laying a foundation for uniform dispersion in subsequent melt blending. Stepwise melt blending relies on the stepwise reaction control theory of polymer melt blending. The premix added at the main feed port gradually melts in the twin-screw extruder to form a continuous phase, achieving secondary dispersion through screw shearing. A mixture of hyperbranched dynamic crosslinking agent and diphenyl disulfide is injected into the later part of the melting section at the side feed port to prevent premature crosslinking, ensuring processing fluidity and uniform construction of the dynamic network. Finally, the composite material is shaped through extrusion, cooling, and pelletizing.

[0057] The melt blending temperature is 190–200℃, synergistically adapting to the rheology and dynamic functional group reaction kinetics of ABS processing. This ensures complete resin melting, efficient filler dispersion, and activation of dynamic cross-linking reactions. Under these process conditions, all raw materials remain stable. The thermal decomposition temperatures of ABS resin, toughening agent, functionalized graphite nanosheets, copolymers, etc., are all higher than the processing temperature, resulting only in controllable interfacial reactions or dynamic cross-linking. Lubricants and antioxidants also function stably without significant decomposition.

[0058] The rotational speed of the twin-screw extruder is controlled in the range of 250~350 r / min, which can achieve a balance between "shear dispersion and uniform crosslinking": when the rotational speed is below 250 r / min, the melt shear force is insufficient, butadiene functionalized graphite nanosheets are prone to agglomeration, and the dynamic crosslinking agent cannot be uniformly dispersed, resulting in uneven distribution of the dynamic network; when the rotational speed is above 350 r / min, strong shear will destroy the gradient core-shell structure of the structured toughening agent, and at the same time trigger excessive crosslinking of dynamic bonds, resulting in a sharp drop in melt fluidity and fluctuations in the mechanical properties of the product.

[0059] In summary, the primary advantage of this application lies in its precise molecular structure design and synergistic innovation of components. By custom-synthesizing a core-shell structured toughening agent, butadiene-functionalized graphite nanosheets, and a hyperbranched dynamic crosslinking agent with end groups simultaneously modified with furan and thiol groups, the structural characteristics of each functional component were specifically optimized. Combined with the interfacial bridging effect of the styrene-maleic anhydride copolymer, a multi-component system with strong interactions, including chemical bonding, segment entanglement, and π-π conjugation, was constructed. This design breaks through the bottleneck of traditional ABS materials, which struggle to balance strength and toughness, rigidity and repairability, at the molecular level. It achieves a synergistic integration of reinforcement, toughening, and dynamic self-healing functions, forming a structurally stable and performance-balanced multiphase composite material system.

[0060] Secondly, this application possesses the advantages of a scientifically sound and rationally designed preparation process. It employs a melt blending process of "premixing + stepwise side feeding," which achieves preliminary uniform dispersion of non-crosslinked components through premixing, and simultaneously injects dynamically crosslinking-related components in the later stages of the melting process via side feeding. This effectively avoids processing difficulties caused by premature crosslinking, balancing processing flowability and product structural uniformity. The entire process is precisely adapted to the thermal stability and reactivity of each raw material, ensuring the stable existence and full functionality of each component during processing, without ineffective decomposition or side reactions. This guarantees the continuity and stability of the production process while accurately replicating the designed microstructure, achieving efficient transformation from formulation to product performance.

[0061] Finally, the advantages of this application also lie in its high adaptability to performance and application scenarios. Through the synergistic effect of multiple scales and mechanisms, the material ultimately achieves an organic unity of high strength, high toughness, self-healing properties, and good processability, perfectly meeting the stringent requirements of high-end electronic product casings for material mechanical properties, durability, and molding precision. Compared to traditional ABS materials, it has more comprehensive functions, superior performance, and significant technological innovation, providing an efficient solution for upgrading electronic product casing materials and possessing broad application prospects and practical value.

[0062] The ABS composite material described in this application, with its organic combination of high strength, high toughness, self-healing properties, and good processability, can be widely used in the casings and structural components of various high-end electronic products. It is suitable for molding casings of mainstream consumer electronics such as smartphones, tablets, and laptops, and can withstand the impacts and wear of daily use, extending product lifespan. It is also suitable for casings of wearable devices such as smartwatches and wireless headphones, as well as casings of small electronic devices such as routers and power banks. Through precise processing, it can meet the complex shape requirements of different products, balancing aesthetics and durability, providing a high-performance, multi-functional material solution for electronic product casings.

[0063] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards / industry standards / the disclosure herein; if there are no corresponding national standards / industry standards / the disclosure herein, they are performed according to generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer.

[0064] Example 1 The embodiment provides an ABS composite material for electronic product housings, which, by weight, is composed of the following raw materials: 75 parts ABS resin (CAS No. 9003-56-9), 10 parts structured toughening agent (core-shell polybutadiene rubber particles), 2 parts butadiene-functionalized graphite nanosheet filler, 3 parts hyperbranched dynamic crosslinking agent (hyperbranched polyester with end-group modified furan and thiol groups), 1.5 parts styrene-maleic anhydride copolymer (SMA, number average molecular weight ~10000, maleic anhydride content ~20%, CAS No. 26636-24-2), 1.0 part zinc stearate (CAS No. 557-05-1), 0.3 parts antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, CAS No. 6683-19-8), and 0.3 parts diphenyl disulfide (DPDS, CAS No. 882-33-7).

[0065] The preparation method of the structured toughening agent includes the following steps: Step S101 (Preparation of seed latex): Take 250g of commercial polybutadiene rubber (CAS No. 9003-17-2) latex with a solid content of 40% (equivalent to 100g of dry rubber), add 350g of deionized water, stir and keep warm at 70℃ for 45min to obtain a seed latex with a solid content of 15%.

[0066] Step S102 (Preparation of intermediate latex): Add 0.3g potassium oleate (CAS No. 143-18-0) and 0.46g potassium disproportionated rosinate (chemical formula C) to the above seed latex. 19 H 27 A composite emulsifier consisting of COOK (mass ratio 1:1.5) was added, along with 0.38 g of potassium persulfate (CAS No. 7727-21-1) as the first initiator. The system temperature was maintained at 75℃, and the first mixed monomer (45 g of butadiene (CAS No. 106-99-0), 35 g of styrene (CAS No. 100-42-5), and 15 g of acrylonitrile (CAS No. 107-13-1, mass ratio 45:35:15, total mass 95 g) was added dropwise simultaneously and at a constant rate over 4 h using a constant flow pump. After the addition was complete, the reaction was continued at 75℃ for 4.5 h to obtain the intermediate latex.

[0067] Step S103 (Core-shell polymerization and post-treatment): Adjust the temperature of the intermediate latex to 75°C, and add the second mixed monomer emulsion (38g of styrene (CAS No. 100-42-5), 10g of acrylonitrile (CAS No. 107-13-1), and 4g of glycidyl methacrylate (CAS No. 106-91-2, with a mass ratio of 76:20:4 and a total mass of 52g) dropwise at a uniform rate over 3 hours, and simultaneously add 0.08g of potassium persulfate (CAS No. 7727-21-1) as the second initiator; after the dropwise addition is completed, heat the system to 85°C and mature for 3 hours, then use a 5% aluminum sulfate (CAS No. 10043-01-3) solution for coagulation treatment, wash with water, filter, and vacuum dry at 60°C for 24 hours to finally obtain a white powdery structured toughening agent.

[0068] The preparation method of butadiene-functionalized graphite nanosheet filler includes the following steps: Step S201 (Preparation of graphite oxide nanosheets): 5.0 g of graphite nanosheets (CAS No. 7440-44-0, the thickness of the graphite nanosheets is 50 nm, and the number of layers is less than 100) were added to a mixed acid solution composed of 200 mL of concentrated sulfuric acid (CAS No. 7664-93-9) and 50 mL of concentrated nitric acid (CAS No. 7697-37-2). The mixture was stirred vigorously at 40 °C for 8 h. After the reaction was completed, the mixture was poured into a large amount of ice water for dilution. After multiple centrifugations and washing with water until the system was neutral, the mixture was freeze-dried to obtain graphite oxide nanosheets.

[0069] Step S202 (Preparation of acyl chloride graphite nanosheets): 3.0 g of the above-mentioned graphite oxide nanosheets were dispersed in 150 mL of thionyl chloride (CAS No. 7719-09-7), and 1.5 mL of N,N-dimethylformamide (DMF, CAS No. 68-12-2) (1% of the volume of thionyl chloride) was added. The mixture was refluxed at 70 °C for 18 h. After the reaction was completed, excess thionyl chloride was removed by vacuum distillation using a rotary evaporator to obtain acyl chloride graphite nanosheets with acyl chloride groups on the surface.

[0070] Step S203 (Butadiene Grafting Modification): Under an argon atmosphere, 1.0 g of acyl chloride graphite nanosheets, 0.8 g of 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide (CAS No. 908595-77-7) (third initiator), 0.34 g of cuprous bromide (CuBr, CAS No. 7787-70-4), 0.65 g of pentamethyldiethylenetriamine (PMDETA, CAS No. 3030-47-5) (CuBr to PMDETA molar ratio 1:2) and 80 mL of anhydrous toluene (CAS No. 108-88) were added. -3) Add to the reaction flask and activate at 60℃ for 1h; then inject 15g of freshly distilled butadiene (CAS No. 106-99-0) monomer (butadiene to third initiator molar ratio 100:1) through a syringe, and carry out surface-initiated atom transfer radical polymerization at 70℃ for 18h; after the reaction, pour the product into methanol (CAS No. 67-56-1) to precipitate, filter, and then Soxhlet extract with tetrahydrofuran (THF, CAS No. 109-99-9) for 48h to remove free homopolymer. After vacuum drying, black powdered butadiene functionalized graphite nanosheet filler is obtained.

[0071] The preparation method of hyperbranched dynamic crosslinking agent includes the following steps: Step S301 (Preparation of hydroxyl-terminated hyperbranched polyester): In a three-necked reaction flask equipped with a stirrer, a water separator, and a nitrogen inlet tube, 21.8 g (0.10 mol) of pyromellitic anhydride (CAS No. 89-32-7) and 14.7 g (0.11 mol) of trimethylolpropane (CAS No. 77-99-6) (molar ratio 1:1.1) were added, along with 0.18 g of p-toluenesulfonic acid (CAS No. 104-15-4) (0.5% of the total monomer mass) as a catalyst. Under nitrogen protection, the temperature was gradually raised to 140 °C, and a melt polycondensation reaction was carried out for 6 h. During the reaction, the generated water was removed through the water separator. After the reaction, a pale yellow viscous hydroxyl-terminated hyperbranched polyester was obtained.

[0072] Step S302 (End-group bifunctional modification): Take 10.0 g (containing 0.03 mol of terminal hydroxyl groups) of the above-mentioned hydroxyl-terminated hyperbranched polyester and dissolve it in 80 mL of anhydrous N,N-dimethylformamide; add 1.68 g (0.015 mol) of 2-furanoic acid (CAS No. 88-14-2), 1.38 g (0.015 mol) of mercaptoacetic acid (CAS No. 68-11-1) to the system sequentially (the molar ratio of terminal hydroxyl groups, 2-furanoic acid, and mercaptoacetic acid is 1:0.5:0.5), and 0.37 g (0. 0.03 mol) of 4-dimethylaminopyridine (DMAP, CAS No. 1122-58-3) and 6.18 g (0.03 mol) of dicyclohexylcarbodiimide (DCC, CAS No. 538-75-0) (DCC to total carboxyl molar ratio 1:1) were reacted at 50 °C for 24 h. After the reaction was completed, the generated dicyclohexylurea was removed by filtration, and the filtrate was added dropwise to a large amount of ice-cold diethyl ether for precipitation. The precipitate was washed three times with diethyl ether and then dried under vacuum at 40 °C to constant weight to obtain a light brown solid, which is the hyperbranched dynamic crosslinking agent.

[0073] Based on the raw material composition of the ABS composite material described above, this embodiment also provides a method for preparing the ABS composite material, the specific steps of which are as follows: Step S1 (premixing): Add ABS resin, structured toughening agent, butadiene functionalized graphite nanosheets, styrene-maleic anhydride copolymer, zinc stearate, and antioxidant 1010 to a high-speed mixer and mix for 5 minutes at room temperature to obtain the premixed material.

[0074] Step S2 (Mel Blending and Dynamic Crosslinking): The above premixed material is added from the main feed port of a twin-screw extruder (screw diameter 35mm, length-to-diameter ratio 40:1). The temperatures of each section of the extruder are set as follows: Zone 1 175℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, Zone 5 200℃, Zone 6 195℃, and Die Head 190℃. The hyperbranched dynamic crosslinking agent and diphenyl disulfide are stirred evenly and injected into the system in Zone 4 (middle and rear of the melt section) of the extruder through a side feed pump. The screw speed of the twin-screw extruder is set to 300r / min, and the side feed rate is 1.0g / min. After melt blending, extrusion, water cooling, and pelletizing, ABS composite material pellets are obtained.

[0075] Example 2 This embodiment provides an ABS composite material for electronic product housings. By weight, the composite material is composed of the following raw materials: 80 parts ABS resin, 8 parts structured toughening agent, 3 parts butadiene functionalized graphite nanosheet filler, 4 parts hyperbranched dynamic crosslinking agent, 2.0 parts styrene-maleic anhydride copolymer, 1.2 parts zinc stearate, 0.4 parts antioxidant 1010, and 0.5 parts diphenyl disulfide.

[0076] The preparation method of the structured toughening agent includes the following steps: Step S101: Take 200g of commercial polybutadiene rubber latex with a solid content of 40%, add 320g of deionized water, stir and keep warm at 72℃ for 50min to obtain seed latex solution with a solid content of 13%.

[0077] Step S102: Add a composite emulsifier consisting of 0.35g potassium oleate and 0.53g potassium disproportionated rosinate to the above seed latex, and simultaneously add 0.49g potassium persulfate as the first initiator; maintain the system temperature at 73℃, and simultaneously and uniformly add the first mixed monomer (40g butadiene, 40g styrene, and 18g acrylonitrile in a mass ratio of 40:40:18, total mass 98g) over 3.5h using a constant flow pump; after the addition is complete, continue the reaction at 73℃ for 5h to obtain the intermediate latex.

[0078] Step S103: Adjust the temperature of the intermediate latex to 73℃, and add the second mixed monomer emulsion (35g styrene, 12g acrylonitrile, 5g glycidyl methacrylate, mass ratio 70:24:6, total mass 52g) dropwise at a uniform rate over 2.5h, while simultaneously adding 0.07g potassium persulfate as the second initiator; after the addition is complete, heat the system to 83℃ and mature for 2.5h, then use a 5% aluminum sulfate solution for coagulation treatment, wash with water, filter, and vacuum dry at 62℃ for 20h to finally obtain a white powdery structured toughening agent.

[0079] The preparation method of butadiene-functionalized graphite nanosheet filler includes the following steps: Step S201: Add 4.5g of graphite nanosheets to a mixed acid solution consisting of 180mL of concentrated sulfuric acid and 45mL of concentrated nitric acid, and stir vigorously at 38℃ for 7h. After the reaction is completed, pour the mixture into a large amount of ice water to dilute it. After multiple centrifugations and washing with water until the system is neutral, freeze-dry to obtain graphite oxide nanosheets.

[0080] Step S202: Disperse 2.8g of the above-mentioned graphene oxide nanosheets in 140mL of thionyl chloride, add 1.2mL of N,N-dimethylformamide, and reflux at 68℃ for 20h; after the reaction is completed, remove excess thionyl chloride by vacuum distillation using a rotary evaporator to obtain acyl chloride graphene nanosheets with acyl chloride groups on the surface.

[0081] Step S203: Under an argon atmosphere, 0.9 g of acyl chloride graphite nanosheets, 0.7 g of 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide, 0.30 g of cuprous bromide, 0.6 g of pentamethyldiethylenetriamine, and 75 mL of anhydrous toluene were added to a reaction flask and activated at 58 °C for 1.2 h. Subsequently, 14 g of freshly distilled butadiene monomer was injected through a syringe, and surface-initiated atom transfer radical polymerization was carried out at 68 °C for 16 h. After the reaction, the product was poured into methanol to precipitate, filtered, and then extracted with tetrahydrofuran using a Soxhlet extractor for 40 h to remove free homopolymer. After vacuum drying, black powdered butadiene functionalized graphite nanosheet filler was obtained.

[0082] The preparation method of hyperbranched dynamic crosslinking agent includes the following steps: Step S301: In a three-necked reaction flask equipped with a stirrer, a water separator, and a nitrogen inlet tube, add 21.8 g of pyromellitic anhydride, 15.3 g of trimethylolpropane, and 0.2 g of p-toluenesulfonic acid as a catalyst; under nitrogen protection, gradually raise the temperature to 138 °C and carry out a melt polycondensation reaction for 7 h. During the reaction, remove the generated water through the water separator. After the reaction, a pale yellow viscous terminal hydroxyl hyperbranched polyester is obtained.

[0083] Step S302: Take 11.0 g of the above-mentioned hydroxyl-terminated hyperbranched polyester (containing 0.033 mol of hydroxyl-terminated molecules) and dissolve it in 85 mL of anhydrous N,N-dimethylformamide; add 2.02 g of 2-furanic acid, 1.66 g of mercaptoacetic acid, 0.4 g of 4-dimethylaminopyridine and 7.42 g of dicyclohexylcarbodiimide to the system in sequence; react at 52 °C for 22 h; after the reaction is completed, filter to remove the generated dicyclohexylurea, and add the filtrate dropwise to a large amount of ice-cold diethyl ether for precipitation; wash the precipitate three times with diethyl ether and dry it under vacuum at 42 °C to constant weight to obtain a light brown solid, which is the hyperbranched dynamic crosslinking agent.

[0084] Based on the raw material composition of the ABS composite material described above, this embodiment also provides a method for preparing the ABS composite material, the specific steps of which are as follows: Step S1: Add ABS resin, structured toughening agent, butadiene functionalized graphite nanosheets, styrene-maleic anhydride copolymer, zinc stearate, and antioxidant 1010 to a high-speed mixer and mix for 5 minutes at room temperature to obtain a premixed material.

[0085] Step S2: Add the above premixed material through the main feed port of the twin-screw extruder. Set the temperatures of each section of the extruder as follows: Zone 1 170℃, Zone 2 180℃, Zone 3 190℃, Zone 4 195℃, Zone 5 195℃, Zone 6 190℃, and Die Head 185℃. Mix the hyperbranched dynamic crosslinking agent and diphenyl disulfide evenly and inject the mixture into the fourth zone of the extruder through a side feed pump. Set the screw speed of the twin-screw extruder to 320 r / min and the side feed rate to 1.2 g / min. After melt blending, extrusion, water cooling, and pelletizing, the material is used to obtain ABS composite material pellets.

[0086] Example 3 This embodiment provides an ABS composite material for electronic product housings. By weight, the composite material is composed of the following raw materials: 72 parts ABS resin, 12 parts structured toughening agent, 1.5 parts butadiene functionalized graphite nanosheet filler, 2.5 parts hyperbranched dynamic crosslinking agent, 1.0 part styrene-maleic anhydride copolymer, 0.8 parts zinc stearate, 0.2 parts antioxidant 1010, and 0.2 parts diphenyl disulfide.

[0087] The preparation method of the structured toughening agent includes the following steps: Step S101: Take 300g of commercial polybutadiene rubber latex with a solid content of 40%, add 380g of deionized water, stir and keep warm at 68℃ for 40min to obtain seed latex solution with a solid content of 16%.

[0088] Step S102: Add a composite emulsifier consisting of 0.27g potassium oleate and 0.4g potassium disproportionate to the above seed latex, and simultaneously add 0.29g potassium persulfate as the first initiator; maintain the system temperature at 77℃, and simultaneously and uniformly add the first mixed monomer (50g butadiene, 32g styrene, and 13g acrylonitrile in a mass ratio of 50:32:13, total mass 95g) over 4.5h using a constant flow pump; after the addition is complete, continue the reaction at 77℃ for 4h to obtain the intermediate latex.

[0089] Step S103: Adjust the temperature of the intermediate latex to 77℃, and add the second mixed monomer emulsion (40g styrene, 9g acrylonitrile, 3g glycidyl methacrylate, mass ratio 80:18:6, total mass 52g) dropwise at a uniform rate over 3.5h, while simultaneously adding 0.09g potassium persulfate as the second initiator; after the addition is complete, heat the system to 87℃ and mature for 3.5h, then use a 5% aluminum sulfate solution for coagulation treatment, wash with water, filter, and vacuum dry at 58℃ for 26h to finally obtain a white powdery structured toughening agent.

[0090] The preparation method of butadiene-functionalized graphite nanosheet filler includes the following steps: Step S201: Add 5.5g of graphite nanosheets to a mixed acid solution consisting of 220mL of concentrated sulfuric acid and 55mL of concentrated nitric acid, and stir vigorously at 42℃ for 9h. After the reaction is completed, pour the mixture into a large amount of ice water to dilute it. After multiple centrifugations and washing with water until the system is neutral, freeze-dry to obtain graphite oxide nanosheets.

[0091] Step S202: Disperse 3.2g of the above-mentioned graphene oxide nanosheets in 160mL of thionyl chloride, add 1.8mL of N,N-dimethylformamide, and reflux at 72℃ for 16h; after the reaction is completed, remove excess thionyl chloride by vacuum distillation using a rotary evaporator to obtain acyl chloride graphene nanosheets with acyl chloride groups on the surface.

[0092] Step S203: Under an argon atmosphere, 1.1 g of acyl chloride graphite nanosheets, 0.9 g of 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide, 0.37 g of cuprous bromide, 0.7 g of pentamethyldiethylenetriamine, and 85 mL of anhydrous toluene were added to a reaction flask and activated at 62 °C for 0.8 h. Subsequently, 16 g of freshly distilled butadiene monomer was injected through a syringe, and surface-initiated atom transfer radical polymerization was carried out at 72 °C for 20 h. After the reaction, the product was poured into methanol to precipitate, filtered, and then extracted with tetrahydrofuran using a Soxhlet extractor for 52 h to remove free homopolymer. After vacuum drying, black powdered butadiene functionalized graphite nanosheet filler was obtained.

[0093] The preparation method of hyperbranched dynamic crosslinking agent includes the following steps: Step S301: In a three-necked reaction flask equipped with a stirrer, a water separator, and a nitrogen inlet tube, add 21.8 g of pyromellitic anhydride, 14.1 g of trimethylolpropane, and 0.18 g of p-toluenesulfonic acid as a catalyst; under nitrogen protection, gradually raise the temperature to 142 °C and carry out a melt polycondensation reaction for 5 h. During the reaction, remove the generated water through the water separator. After the reaction, a pale yellow viscous terminal hydroxyl hyperbranched polyester is obtained.

[0094] Step S302: Take 9.0 g of the above-mentioned hydroxyl-terminated hyperbranched polyester (containing 0.027 mol of hydroxyl-terminated molecules) and dissolve it in 75 mL of anhydrous N,N-dimethylformamide; add 1.38 g of 2-furanic acid, 1.10 g of mercaptoacetic acid, 0.33 g of 4-dimethylaminopyridine and 5.6 g of dicyclohexylcarbodiimide to the system in sequence; react at 48 °C for 26 h; after the reaction is completed, filter to remove the generated dicyclohexylurea, and add the filtrate dropwise to a large amount of ice-cold diethyl ether for precipitation; wash the precipitate three times with diethyl ether and dry it under vacuum at 38 °C to constant weight to obtain a light brown solid, which is the hyperbranched dynamic crosslinking agent.

[0095] Based on the raw material composition of the ABS composite material described above, this embodiment also provides a method for preparing the ABS composite material, the specific steps of which are as follows: Step S1: Add ABS resin, structured toughening agent, butadiene functionalized graphite nanosheets, styrene-maleic anhydride copolymer, zinc stearate, and antioxidant 1010 to a high-speed mixer and mix for 5 minutes at room temperature to obtain a premixed material.

[0096] Step S2: Add the above premixed material through the main feed port of the twin-screw extruder. Set the temperatures of each section of the extruder as follows: Zone 1 180℃, Zone 2 190℃, Zone 3 200℃, Zone 4 200℃, Zone 5 200℃, Zone 6 200℃, and Die head 195℃. Mix the hyperbranched dynamic crosslinking agent and diphenyl disulfide evenly and inject the mixture into the fourth zone of the extruder through a side feed pump. Set the screw speed of the twin-screw extruder to 280 r / min and the side feed rate to 0.8 g / min. After melt blending, extrusion, water cooling, and pelletizing, the material is used to obtain ABS composite material pellets.

[0097] Comparative Example 1 This comparative example is modified from the one disclosed in Example 1 as follows: The raw materials of ABS composite materials do not contain structural toughening agents.

[0098] Comparative Example 2 This comparative example is modified from the one disclosed in Example 1 as follows: The raw materials of ABS composite materials do not contain butadiene-functionalized graphite nanosheet fillers.

[0099] Comparative Example 3 This comparative example is modified from the one disclosed in Example 1 as follows: The raw materials of ABS composite materials do not contain hyperbranched dynamic crosslinking agents.

[0100] Comparative Example 4 This comparative example is modified from the one disclosed in Example 1 as follows: The raw materials of ABS composite materials do not contain styrene-maleic anhydride copolymer.

[0101] Comparative Example 5 This comparative example is modified from the one disclosed in Example 1 as follows: The raw materials of ABS composite materials do not contain diphenyl disulfide.

[0102] The performance of the ABS composite materials obtained in Examples 1-3 and Comparative Examples 1-5 was measured, and the performance data are shown in Table 1.

[0103] Before testing, all samples were injection molded into specimens of specified dimensions according to standard methods and conditioned for no less than 48 hours in a standard environment at 23±2℃ and 50±10% relative humidity. Specific test items and methods are as follows: Tensile properties: Tested according to standard ISO 527-1:2019. A universal testing machine was used, with type 1A dumbbell specimens and a tensile speed of 50 mm / min. Tensile strength (maximum stress) and elongation at break were recorded.

[0104] Bending performance: Tested according to standard ISO 178:2019. The three-point bending method was used, with a specimen size of 80mm × 10mm × 4mm, a span of 64mm, and a test speed of 2mm / min. Bending strength and flexural modulus were recorded.

[0105] Impact performance: Tested according to standard ISO179-1:2010. The simple supported beam impact test was adopted, and the specimen was a V-notch specimen (dimensions 80mm×10mm×4mm), and its notched impact strength was tested at 23℃.

[0106] Heat distortion temperature: Tested according to standard ISO 75-1 2020. The specimen was placed flat, with a load of 1.80 MPa and a heating rate of 120℃ / h. The temperature at which the specimen's bending deformation reached 0.34 mm was recorded as the heat distortion temperature.

[0107] Melt flow rate: Tested according to standard ISO 1133-1 2011. Under standard conditions of 220℃ and 10.00 kg load, the mass of melt passing through a standard die every 10 minutes was measured, in g / 10min.

[0108] Surface hardness: Tested according to standard ASTM D785-08 (2015). A Rockwell hardness tester was used, with the R scale.

[0109] Self-healing efficiency assessment: To quantify the self-healing ability of materials, the following experiment was designed: First, tensile specimens were prepared according to ISO 527 standards. Using a custom-made fixture equipped with a thickness gauge and a standard blade, a single through-crack with a length of 10.0 ± 0.5 mm and a depth of 0.50 ± 0.05 mm (i.e., 50% of the specimen thickness) was pre-cut on the specimen surface. Then, the cracked specimen was placed in an 80°C forced-air drying oven and left to stand for 2 hours. After repair, its tensile strength was tested again according to ISO 527 standards. The self-healing efficiency was calculated as the ratio of the tensile strength before and after repair, using the formula: Self-healing efficiency (%) = (σ... r / σ i )×100%, where σ i σ represents the initial tensile strength of the undamaged spline.r This represents the tensile strength of the repaired spline.

[0110] Table 1. Properties of ABS composite materials in Examples 1-3 and Comparative Examples 1-5

[0111] As shown in Table 1, Examples 1-3, as ABS composite materials for electronic product casings with synergistic modification of all components, exhibit superior core properties compared to their comparative counterparts. Specifically, Examples 1-3 show tensile strength ranging from 51.3 to 57.8 MPa, elongation at break ranging from 28.5% to 42.1%, flexural strength ranging from 78.4 to 86.3 MPa, flexural modulus ranging from 2.68 to 3.02 GPa, and notched impact strength of simply supported beams ranging from 50.5 to 65.1 kJ / m². 2 The heat distortion temperature (1.8MPa) ranges from 98.8 to 103.2℃, the melt flow rate (220℃ / 10kg) ranges from 10.8 to 14.2 g / 10min, the Rockwell hardness (R scale) ranges from 110.8 to 114.2 HRR, and the self-healing efficiency ranges from 82.5 to 85.3%.

[0112] Comparative Example 1 (without structured toughening agent) showed severe deterioration in impact toughness and plasticity. The most significant feature of this data set was a sharp drop in notched impact strength to 22.7 kJ / m. 2 The elongation at break decreased to 15.8%, the lowest among all groups. This directly proves that the structured toughening agent is the core energy absorption and toughening unit of this material system, and its core-shell structure can efficiently initiate and terminate creasing. Its self-healing efficiency was only 22.5%, which is not due to dynamic network failure, but rather because cracks generated in the brittle matrix are difficult to effectively repair through interfacial bonding, reflecting the indirect correlation between toughness and repair effect.

[0113] Comparative Example 2 (butadiene-free functionalized graphite nanosheets) showed a significant decrease in rigidity, strength, and heat resistance. This group exhibited obvious shortcomings in flexural strength (71.8 MPa), flexural modulus (2.55 GPa), and heat distortion temperature (92.3 °C). This confirms the core role of functionalized graphite nanosheets as a "rigid framework": they efficiently transfer stress through strong interfacial bonding (π-π conjugation and segment entanglement), thereby improving rigidity and heat resistance. Its self-healing efficiency reached 78.0%, indicating that the dynamic network was not fundamentally affected. The slight decrease in performance after repair may be related to the reduced overall load-bearing capacity caused by filler deficiency.

[0114] Comparative Example 3 (without hyperbranched dynamic crosslinking agent) completely lost its self-healing function, and all mechanical properties of this group (such as impact strength 49.8 kJ / m) were also affected. 2Although the self-healing efficiency decreased compared to the previous example, it was still considered good, indicating that the basic mechanical framework remained intact. However, its self-healing efficiency was marked as "--" (undetectable), indicating a complete and undeniable loss of self-healing ability. This irrefutably proves that the hyperbranched dynamic crosslinking agent is the only chemical source that endows the material with self-healing properties, and the dynamic covalent network it constructs is the cornerstone for realizing the mechanism of "sacrificial bond" breakage and recombination.

[0115] Comparative Example 4 (styrene-maleic anhydride copolymer without SMA) showed a weakening of interfacial synergy, leading to a comprehensive decline in performance. This set of data exhibited a comprehensive but not extreme decrease: impact strength (40.5 kJ / m²) 2 The flexural strength (74.1 MPa), modulus (2.62 GPa), and self-healing efficiency (65.4%) all showed significant decreases. This highlights the crucial role of SMA as a "molecular bridge": it strengthens the interfacial bond between the toughening agent, filler, and ABS matrix through chemical reactions. Its absence leads to decreased stress transfer efficiency and makes the interface prone to becoming a defect point, thereby weakening the synergy of reinforcement, toughening, and repair effects.

[0116] Comparative Example 5 (without diphenyl disulfide, DPDS) showed severe damage to its self-healing network, resulting in decreased mechanical properties (e.g., impact strength 56.1 kJ / m). 2 The results are very similar to those in Example 1, indicating that the skeletal function of the dynamic crosslinking agent and the toughening system remain effective. However, its self-healing efficiency plummeted to 32.6%. This proves that DPDS is not a simple additive, but an indispensable "crosslinking regulator" and "exchange medium" for the dynamic crosslinking network. Its absence severely hinders the full progress of the disulfide bond exchange reaction, greatly reducing the reorganization ability of the dynamic network and resulting in low repair efficiency.

[0117] The ABS composite material of this application successfully solves the technical problem of the difficulty in achieving strength, toughness, heat resistance and functionalization in traditional materials through the multi-component design and precise synergy of structured toughening agent (dominant toughening), butadiene functionalized graphite nanosheets (dominant reinforcement and heat resistance), hyperbranched dynamic crosslinking agent and DPDS (jointly dominant self-healing), and SMA (dominant interface synergy).

[0118] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1 to 6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship. Proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional expression, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0119] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An ABS composite material for electronic product housings, characterized in that, The composite material, by weight, is composed of the following raw materials: ABS resin: 70-85 parts, structural toughening agent: 5-15 parts, butadiene-functionalized graphite nanosheet filler: 1-5 parts, hyperbranched dynamic crosslinking agent: 2-8 parts, styrene-maleic anhydride copolymer: 0.5-3 parts, diphenyl disulfide: 0.1-1 parts, lubricant: 0.5-1.5 parts, antioxidant: 0.1-0.5 parts; The structured toughening agent is a core-shell structured polybutadiene rubber particle, wherein the core layer of the core-shell structured polybutadiene rubber particle is polybutadiene rubber, the transition layer is a butadiene-styrene-acrylonitrile terpolymer, and the shell layer is a styrene-acrylonitrile copolymer rich in epoxy functional groups. The hyperbranched dynamic crosslinking agent is a hyperbranched polyester with end groups simultaneously modified with furan groups and thiol groups.

2. The ABS composite material for electronic product housings according to claim 1, characterized in that, The method for preparing the structured toughening agent includes the following steps: S101. Add water to polybutadiene rubber latex, and then keep it at 65-75℃ for 30-60 minutes to obtain seed latex solution. S102. Add an emulsifier and a first initiator to the seed latex, then add a first mixed monomer composed of butadiene, styrene and acrylonitrile dropwise, and continue the reaction at 70-80°C for 3-6 hours to obtain an intermediate latex. S103. Adjust the temperature of the intermediate latex to 70-85°C, then add dropwise a second mixed monomer composed of styrene, acrylonitrile and glycidyl methacrylate, and add a second initiator. After the dropwise addition is complete, raise the temperature to 80-90°C and mature for 2-4 hours. After coagulation, washing and drying, the structured toughening agent is obtained.

3. The ABS composite material for electronic product housings according to claim 2, characterized in that, The solid content of the seed latex is 10-25%; The mass ratio of butadiene, styrene and acrylonitrile is (40-60):(30-50):(10-20); The emulsifier is a complex of potassium oleate and disproportionated rosin soap, wherein the mass ratio of potassium oleate to disproportionated rosin soap is 1:(0.5-2), and the mass of the emulsifier is 0.4-1.0% of the total mass of the first mixed monomers. The first initiator is potassium persulfate, and the mass of the first initiator is 0.2% to 0.5% of the total mass of the first mixed monomers. The mass ratio of styrene, acrylonitrile and glycidyl methacrylate is (70-85):(15-25):(5-10); The second initiator is potassium persulfate, and the mass of the second initiator is 0.1 to 0.3% of the total mass of the second mixed monomers.

4. The ABS composite material for electronic product housings according to claim 1, characterized in that, The preparation method of the butadiene-functionalized graphite nanosheet filler includes the following steps: S201. Add graphite nanosheets to a mixed acid solution and stir the reaction at 30-50°C for 4-12 hours. After post-treatment, obtain graphite oxide nanosheets. S202. The graphene oxide nanosheets are dispersed in thionyl chloride, and then N,N-dimethylformamide is added. The mixture is refluxed at 60-80°C for 12-24 hours. Excess thionyl chloride is removed by vacuum distillation to obtain acyl chloride graphene nanosheets with acyl chloride groups on the surface. S203. Under an inert atmosphere, the acyl chloride graphite nanosheets, the third initiator, the catalyst and the solvent are mixed and activated at 50-70°C for 0.5-2 hours. Then, butadiene monomer is added and surface-initiated atom transfer radical polymerization is carried out at 60-80°C for 6-24 hours. After post-treatment, the butadiene functionalized graphite nanosheet filler is obtained.

5. The ABS composite material for electronic product housings according to claim 4, characterized in that, The volume of the N,N-dimethylformamide is 0.5% to 5% of the volume of the thionyl chloride; The third initiator is 2-bromo-2-methyl-N-(3-(triethoxysilyl)propyl)propionamide, and the molar ratio of the butadiene monomer to the third initiator is (50-300):1; The catalyst is a complex of cuprous bromide and pentamethyldiethylenetriamine, wherein the molar ratio of pentamethyldiethylenetriamine to cuprous bromide is (1.5-3):1, and the molar ratio of cuprous bromide to the third initiator is (1-2):

1.

6. The ABS composite material for electronic product housings according to claim 1, characterized in that, The preparation method of the hyperbranched dynamic crosslinking agent includes the following steps: S301. Mix pyromellitic anhydride, trimethylolpropane and p-toluenesulfonic acid, and then carry out melt polycondensation reaction at 120-160℃ for 4-10h to obtain hyperbranched polyester with hydroxyl end groups. S302. The hyperbranched polyester is dissolved in an organic solvent, and then 2-furan carboxylic acid, mercaptoacetic acid, 4-dimethylaminopyridine and dicyclohexylcarbodiimide are added in sequence. The mixture is reacted at 40-80°C for 12-36 hours. After post-treatment, the hyperbranched polyester with end groups modified with furan groups and thiol groups is obtained.

7. The ABS composite material for electronic product housings according to claim 6, characterized in that, The molar ratio of the pyromellitic anhydride to the trimethylolpropane is 1:(1.05-1.3); The mass of the p-toluenesulfonic acid is 0.5% to 1.5% of the total mass of the pyromellitic anhydride and the trimethylolpropane. The molar ratio of the terminal hydroxyl groups of the hyperbranched polyester, the 2-furan carboxylic acid, and the mercaptoacetic acid is 1:(0.4-0.6):(0.4-0.6). The molar ratio of the total carboxyl groups of the dicyclohexylcarbodiimide to that of the 2-furan carboxylic acid and the mercaptoacetic acid is (1-1.2):1; The molar ratio of the total carboxyl groups of the 4-dimethylaminopyridine to the 2-furan carboxylic acid and the mercaptoacetic acid is (0.05-0.15):

1.

8. The ABS composite material for electronic product housings according to claim 1, characterized in that, The lubricant is zinc stearate; The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid].

9. A method for preparing an ABS composite material for electronic product housing according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1. The ABS resin, the structured toughening agent, the butadiene-functionalized graphite nanosheet filler, the styrene-maleic anhydride copolymer, the lubricant and the antioxidant are premixed to obtain a premixed material. S2. The premixed material is added to the twin-screw extruder through the main feed port. At the same time, the hyperbranched dynamic crosslinking agent is mixed with diphenyl disulfide and injected into the rear section of the melting section of the twin-screw extruder through the side feed port. After melt blending, extrusion, cooling and pelletizing, the ABS composite material is obtained.

10. The method for preparing ABS composite material for electronic product housings according to claim 9, characterized in that, The melt blending temperature is 190–200°C; The screw speed of the twin-screw extruder is 250~350 r / min, and the side feed rate of the hyperbranched dynamic crosslinking agent and diphenyl disulfide is 0.8~1.2 g / min.

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