Preparation process of ABS (Acrylonitrile Butadiene Styrene) antibacterial plastic plate

Abstract

The invention discloses a preparation process of an ABS (acrylonitrile butadiene styrene) antibacterial plastic plate, which comprises the following steps: mixing ABS resin, a PBrMAP-11 antibacterial agent, a plasticizer and an additive to obtain antibacterial master batch, mixing the antibacterial master batch and ABS resin to obtain antibacterial mixed granules, adding modified MWC1NTs and a nanoparticle template into the antibacterial mixed granules, mixing to obtain antibacterial plastic granules, adding the antibacterial plastic granules into the antibacterial master batch, and mixing to obtain the ABS antibacterial plastic plate. And carrying out compression molding to obtain the ABS antibacterial plastic plate. By adding the ABS resin twice, the distribution of the MWCNTs in a matrix is optimized, a uniform stress transfer network is formed, the MWCNTs with the optimized length-diameter ratio can more effectively transfer stress and disperse stress concentration points, so that the mechanical property of the material is remarkably improved, the distribution of an antibacterial agent is gradually optimized, the antibacterial agent can more uniformly act on the surfaces of bacteria, and the antibacterial property of the antibacterial agent is improved. The MWCNTs provide more adsorption sites, and the infiltration capacity of the antibacterial agent is enhanced, so that the antibacterial efficiency is improved; compared with the prior art, the antibacterial efficiency and the mechanical property of the plastic plate can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to an ABS antibacterial plastic sheet, and particularly to a preparation process of an ABS antibacterial plastic sheet. Background Art

[0002] With the continuous expansion of the application fields of plastics, the performance requirements for plastic materials are getting higher and higher. Especially in the fields of medical treatment, food packaging, biomaterials, etc., plastics are not only required to have good mechanical properties and processing properties, but also required to have excellent antibacterial properties. Although traditional ABS plastics have the advantages of light weight, low cost, easy processing, etc., they lack antibacterial properties, which limits their application in high-hygiene-standard fields. In recent years, researchers have given plastics antibacterial properties by adding antibacterial agents. The common methods are as follows:

[0003] Silver ion antibacterial agents, organic antibacterial agents and nanomaterials antibacterial. Silver ion antibacterial agents can combine with the negatively charged groups on the bacterial cell membrane through silver ions (Ag + ) to destroy the integrity of the cell membrane, and then interfere with the normal physiological functions of bacteria, ultimately leading to the death of bacteria; organic antibacterial agents are adsorbed on the surface of bacteria through electrostatic action to destroy the bacterial cell membrane, thereby achieving the purpose of antibacterial. Common organic antibacterial agents include quaternary ammonium salts, phenols, etc.; nanomaterials antibacterial, nanomaterials such as titanium dioxide nanoparticles (TiO2), zinc oxide nanoparticles (ZnO), etc., generate free radicals through photocatalysis to destroy the bacterial cell structure and achieve antibacterial effects.

[0004] However, in the process of using ABS plastics for household floors, many antibacterial agents have problems such as non-persistent antibacterial effects and easy precipitation, which affect the performance and application of plastic materials. In addition, how to maintain or even improve the mechanical properties of plastics while improving antibacterial properties is also a problem to be solved. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides a preparation process of an ABS antibacterial plastic sheet.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a preparation process of an ABS antibacterial plastic sheet, including: S1. Mixing ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive in a mass ratio of 60-70:12-15:3-7:2-3 to prepare an antibacterial masterbatch;

[0007] S2. Mixing the antibacterial masterbatch and ABS resin in a mass ratio of 4-6:28-32 to prepare an antibacterial mixed granule;

[0008] S3. Adding modified MWC1NTs and nanoparticle templates to the antibacterial mixed granule and mixing to prepare an antibacterial plastic granule;

[0009] S4. Mold the antibacterial plastic pellets to obtain an ABS antibacterial plastic sheet.

[0010] In a preferred embodiment of the present invention, in step S1, the preparation steps of the PBrMAP-11 antibacterial agent are as follows:

[0011] S11. Prepare an intermediate of bromoalkyl methacrylate;

[0012] S12. Synthesize an antibacterial monomer of alkyl methacryloyloxy triphenylphosphonium bromide through the intermediate of S11;

[0013] S13. Synthesize a poly(alkyl methacryloyloxy triphenylphosphonium bromide) high molecular antibacterial agent through the antibacterial monomer of S12.

[0014] In a preferred embodiment of the present invention, in step S1, the specific steps of the mixing preparation are as follows:

[0015] S14. Mix ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive in a mass ratio of 60-70:12-15:3-7:2-3;

[0016] S15. Add the mixture of S14 into a twin-screw extruder, set the temperature at 200-210 °C and the screw speed at 60-70 rpm, and carry out melt extrusion granulation to obtain an ABS antibacterial masterbatch of PBrMAP-n.

[0017] In a preferred embodiment of the present invention, in step S2, the specific steps are as follows:

[0018] S21. After preparing the antibacterial masterbatch and ABS resin in a mass ratio of 4-6:28-32, carry out dry mixing at room temperature for 5-10 min to ensure that the antibacterial masterbatch is evenly dispersed in the ABS resin;

[0019] S22. Carry out melt blending of the materials mixed in S21 through a twin-screw extruder, and set the extruder temperature at 180-220 °C and the screw speed at 200-300 rpm;

[0020] S23. The melt-blended material is extruded through the die head of the extruder to form a strip, and after the strip is cooled by a cooling water tank, it is cut into antibacterial mixed pellets with uniform particle size by a pelletizer.

[0021] In a preferred embodiment of the present invention, in step S3, the specific steps of the mixing preparation are as follows:

[0022] S31. Pre-compound a nano-particle template and modified MWCNTs to obtain a template-MWCNTs material;

[0023] S32. Prepare the antibacterial mixed pellets obtained in step S2 and the SiO2-MWCNTs composite template according to a preset mass ratio;

[0024] S33. Mix the materials prepared in S32 for 5 - 10 min to ensure uniform dispersion of each component;

[0025] S34. Carry out melt blending of the mixed materials through a twin-screw extruder, with an extrusion temperature of 180 - 220 °C and a screw rotation speed of 200 - 300 rpm;

[0026] S35. Extrude the molten material in S34 into strips through a die head, quickly cool and shape it through a cooling water tank, and cut the cooled strip into particles with uniform particle size using a granulator to obtain the final antibacterial plastic pellets.

[0027] In a preferred embodiment of the present invention, in step S31, the specific steps of pre-composite are as follows:

[0028] S311. Mix the modified SiO2 nanoparticles, acid-treated MWCNTs, and ethanol according to a mass ratio of 1 - 2:1 - 2:100 - 120;

[0029] S312. After mixing in S311, perform ultrasonic treatment for 1 - 2 h;

[0030] S313. Centrifuge at 10000 - 12,000 rpm for 12 - 15 min to collect the composite, wash it 3 times with ethanol, and vacuum dry it at 50 - 60 °C for 11 - 12 h to obtain the SiO2-MWCNTs composite template.

[0031] In a preferred embodiment of the present invention, in step S3, the preparation steps of modified MWC1NTs are as follows:

[0032] S3111. Weigh MWCNTs and γ-methacryloxypropyltrimethoxysilane according to a mass ratio of 98 - 102:1 - 2;

[0033] S3112. Acid-treat the MWCNTs;

[0034] S3113. Disperse the acid-treated MWCNTs;

[0035] S3114. Place the MWCNTs solution dispersed in S33 in an oil bath at 50 - 60 °C, add KH570, and react for 7 - 8 h;

[0036] S3115. Filter the MWCNTs treated in S34, wash the filter residue three times with absolute ethanol, and place the filter residue in a vacuum oven to dry to constant weight to obtain MWCNTs.

[0037] In a preferred embodiment of the present invention, in step S3112, the specific steps are as follows:

[0038] S31121. Add MWCNTs to the mixed acid solution and stir to obtain a mixed solution;

[0039] S31122. Ultrasonically treat the mixed solution at a frequency of 40 - 50 kHz and a power of 200 - 400 w for 1 - 2 h;

[0040] S31123. Dilute the ultrasonically treated mixed solution with water to neutrality, centrifuge for 15 - 30 min, discard the supernatant, and repeat centrifugal washing 2 - 3 times until there are no sulfate ions in the supernatant;

[0041] S31124. Dry the washed MWCNTs precipitate at 80 - 90 °C for 12 - 24 h to obtain acidified MWCNTs.

[0042] In a preferred embodiment of the present invention, in step S32, the preset mass ratio is 90 - 95:5 - 10.

[0043] In a preferred embodiment of the present invention, in step S4, the specific steps are as follows:

[0044] S41. Dry the antibacterial plastic pellets in a vacuum drying oven at 60 - 80 °C for 12 - 13 hours to remove moisture. Seal the dried pellets to avoid moisture absorption;

[0045] S42. Add the dried antibacterial plastic pellets to the hopper of the molding press. Install the mold on the molding press, set the mold temperature to 180 - 220 °C, start the molding press, press the pellets into the mold, apply a pressure of 10 - 20 MPa, and hold the pressure for 5 - 10 minutes to ensure that the material completely fills the mold and cures;

[0046] S43. Use a mold release agent or manually demold to remove the formed ABS antibacterial plastic plate from the mold.

[0047] The present invention solves the defects in the background technology and has the following beneficial effects:

[0048] (1) The present invention prepares an antibacterial masterbatch by mixing ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive according to a mass ratio, obtains an antibacterial masterbatch, mixes the antibacterial masterbatch with ABS resin according to a mass ratio to obtain an antibacterial mixed granule, adds modified MWC1NTs and a nanoparticle template to the antibacterial mixed granule, mixes and prepares an antibacterial plastic granule, and molds the antibacterial plastic granule to obtain an ABS antibacterial plastic plate; the quaternary phosphonium salt group (-P+) of the PBrMAP-11 antibacterial agent destroys the integrity of the bacterial cell membrane through electrostatic action, and at the same time, the high specific surface area and surface functional groups of the modified MWCNTs enhance the antibacterial The dispersibility of the antimicrobial agent enables it to act more evenly on the bacterial surface. By adding ABS resin twice, the distribution of MWCNTs in the matrix is ​​optimized, forming a uniform stress transfer network. MWCNTs with optimized aspect ratio can transfer stress more effectively and disperse stress concentration points, thereby significantly improving the mechanical properties of the material. The distribution of the antimicrobial agent is gradually optimized so that it can act more evenly on the bacterial surface. MWCNTs provide more adsorption sites and enhance the penetration ability of the antimicrobial agent, thereby improving the antibacterial efficiency. Compared with the existing technology, when ABS plastic is used in household floors, the antibacterial efficiency and mechanical properties of plastic boards can be significantly improved.

[0049] (2) The present invention significantly improves the mechanical properties of the ABS antibacterial plastic plate by precisely controlling the aspect ratio of MWCNTs and modifying the surface. The carboxyl groups (-COOH) and hydroxyl groups (-OH) on the surface of the modified MWCNTs form strong intermolecular interactions (such as hydrogen bonds) with the ABS matrix, thereby enhancing the cohesive force of the material. At the same time, the porous structure of the nanoparticle template provides additional mechanical anchoring, further improving the mechanical properties of the material. Experimental data show that the tensile strength of the present invention reaches 55 MPa, the flexural strength reaches 80 MPa, and the impact strength reaches 10 kJ / m 2 , which are superior to the comparison scheme without modified MWCNTs and nanoparticle templates. Compared with the existing technology, the material is more reliable when subjected to tensile, bending and impact loads.

[0050] (3) The present invention can precisely control the aspect ratio of MWCNTs by changing the acid treatment time, thereby optimizing the comprehensive performance of the material. Experiments show that when the aspect ratio is around 196:1, the mechanical properties and antibacterial properties of the material reach an optimal balance. This precise control of the aspect ratio provides a new idea for optimizing material performance, enabling the material to adjust its performance according to demand in different application scenarios, and has broad application prospects. By controlling the aspect ratio, the interaction between MWCNTs and the matrix can be optimized at the molecular level, achieving an optimal balance between mechanical properties and antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0052] Figure 1 is a flowchart of a preferred embodiment of the present invention;

[0053] Figure 2 is a flowchart of the preparation of MWCNTs; Detailed implementation manners

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0055] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0056] As Figure 1 shown, a preparation process of an ABS antibacterial plastic sheet includes:

[0057] S1. Mix and prepare ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive according to a mass ratio of 60-70:12-15:3-7:2-3 to obtain an antibacterial masterbatch;

[0058] S2. Mix and prepare the antibacterial masterbatch and ABS resin according to a mass ratio of 4-6:28-32 to obtain an antibacterial mixed granule;

[0059] S3. Add modified MWC1NTs and nanoparticle templates to the antibacterial mixed granule and mix and prepare to obtain an antibacterial plastic granule;

[0060] S4. Mold the antibacterial plastic granule to obtain an ABS antibacterial plastic sheet.

[0061] Specifically, the ABS plastic particles are PA-757 ABS plastic particles produced by Chi Mei Industrial Co., Ltd., which have good mechanical properties and processing properties and are the basic raw materials for preparing antibacterial plastics.

[0062] Specifically, ABS resin is added twice here, and the functions are as follows:

[0063] The first addition of ABS resin (step S1): When preparing the antibacterial masterbatch, the ABS resin serves as the matrix, and the PBrMAP-11 antibacterial agent, plasticizer, and additives are evenly dispersed. The purpose of this stage is to form a stable antibacterial masterbatch to ensure the uniform distribution of the antibacterial agent and other additives in the matrix.

[0064] The second addition of ABS resin (step S2): When preparing the antibacterial mixed pellets, ABS resin is added again to further dilute the concentration of the antibacterial agent and ensure the uniform distribution of the antibacterial agent in the matrix. This step helps to reduce the agglomeration phenomenon of the antibacterial agent and improve its dispersibility.

[0065] By adding ABS resin twice, the viscosity and fluidity of the matrix are gradually adjusted, so as to better disperse the modified MWCNTs. The MWCNTs with optimized aspect ratio can be better dispersed in the matrix, forming a uniform network structure and reducing the agglomeration phenomenon.

[0066] It should be noted that in the first addition of ABS resin, the carboxyl groups (-COOH) and hydroxyl groups (-OH) on the surface of the modified MWCNTs form hydrogen bonds and other intermolecular forces with the polar groups (such as nitrile groups) in the ABS matrix. As the reinforcing phase, MWCNTs begin to form a preliminary stress transfer network in the matrix through its high modulus and rigid structure. At the same time, the ABS resin serves as the matrix to ensure the uniform distribution of the PBrMAP-11 antibacterial agent.

[0067] When the second addition of ABS resin is made, more ABS resin further enhances the intermolecular interaction. The gradual addition of ABS resin makes the combination between MWCNTs and the matrix closer, improves the cohesion of the material, and further optimizes the distribution of MWCNTs, making the stress transfer network more uniform and effective. Moreover, more ABS resin further dilutes the concentration of the antibacterial agent and ensures its uniform distribution. This step helps to reduce the agglomeration phenomenon of the antibacterial agent and improve its dispersibility.

[0068] By adding ABS resin twice, the distribution of MWCNTs in the matrix is optimized, and a uniform stress transfer network is formed. The MWCNTs with optimized aspect ratio can transfer stress more effectively and disperse stress concentration points, thus significantly improving the mechanical properties of the material; by adding ABS resin twice, the distribution of the antibacterial agent is gradually optimized, enabling it to act more uniformly on the surface of bacteria. MWCNTs provide more adsorption sites and enhance the penetration ability of the antibacterial agent, thereby improving the antibacterial efficiency.

[0069] In step S1, the preparation steps of the PBrMAP-11 antibacterial agent are as follows:

[0070] S11. Prepare an intermediate of bromoalkyl methacrylate;

[0071] S12. Synthesize an antibacterial monomer of alkyloxytriphenylphosphonium bromide methacrylate through the intermediate of S11;

[0072] S13. Synthesize a polymeric antibacterial agent of alkyloxytriphenylphosphonium bromide methacrylate through the antibacterial monomer of S12.

[0073] Specifically, in step S11, the specific steps for preparing the intermediate of bromoalkyl methacrylate (BrMA-11) are as follows:

[0074] S111. Add 11-bromo-1-undecanol, triethylamine, and dichloromethane into a single-necked flask according to a mass ratio of 25:10:100, stir and dissolve to obtain a reaction device;

[0075] S112. Place the reaction device in an ice bath, and dropwise add methacryloyl chloride. After the dropping is completed, continue to react in the ice bath for 1 h, then remove the ice bath and continue to react at room temperature for 24 h;

[0076] S113. After the reaction in S112 ends, rotary evaporate to remove dichloromethane with a rotary evaporator, purify the concentrated solution by column chromatography, and use ethyl acetate:petroleum ether = 1:10 (v / v) as the eluent on a silica gel column;

[0077] S114. Collect the eluate, rotary evaporate to remove the solvent at 55 °C, and then dry to a constant weight in a vacuum drying oven to obtain the intermediate of bromoalkyl methacrylate.

[0078] The steps of step S12 are as follows:

[0079] S121. Add BrMA-11, triphenylphosphine, and hydroquinone into a single-necked flask according to a mass ratio of 25:38:0.3, stir and dissolve to obtain a mixture;

[0080] S122. React the mixture in S121 at 80 °C for 72 h;

[0081] S123. Purify the concentrated solution by column chromatography, first elute with ethyl acetate to remove unreacted raw materials and inhibitors, and then elute the product with absolute ethanol to obtain an eluate;

[0082] S124. Collect the eluate, rotary evaporate to remove the solvent at 55 °C, and then dry to a constant weight in a vacuum drying oven to obtain the antibacterial monomer of alkyloxytriphenylphosphonium bromide methacrylate.

[0083] The steps of step S13 are as follows:

[0084] S131. Mix BrMAP-11 and benzoin diethyl ether in a mass ratio of 100:1 and stir until completely dissolved;

[0085] S132. Pour the dissolved product of S131 into a tetrafluoroethylene flat mold and initiate a polymerization reaction under 254 nm ultraviolet light irradiation for 1 h;

[0086] S133. Dry it to constant weight in a vacuum drying oven to obtain a polymethacryloyloxyalkyltriphenylphosphonium bromide polymer antibacterial agent.

[0087] More specifically, PBrMAP-11 is used here because the quaternary phosphonium salt group (-P+) on the molecular chain has a positive charge and can bind to the negatively charged group on the bacterial cell membrane through electrostatic interaction, destroying the integrity of the cell membrane and thus killing bacteria; in addition, the alkyl side chain length of PBrMAP-11 is 11 carbon atoms, and this longer alkyl chain can enhance the hydrophobic interaction with the bacterial cell membrane, further improving the antibacterial efficiency.

[0088] The temperature (T5%) at 5% thermal weight loss of PBrMAP-11 is 250 °C, which can meet the processing temperature of ABS plastic (usually not exceeding 220 °C), ensuring that it will not decompose during the processing and maintaining the antibacterial performance.

[0089] PBrMAP-11 is a non-leaching antibacterial agent and will not precipitate from the material over time, thus ensuring the durability of the antibacterial effect. After soaking in water for 15 days and 30 days, the antibacterial property of PBrMAP-11 / ABS-10 antibacterial plastic not only does not decrease, but instead increases; and the addition of PBrMAP-11 has little effect on the tensile strength, flexural strength and impact strength of ABS plastic, and can maintain the good mechanical properties of the material.

[0090] More specifically, PBrMAP-11 combined with modified MWCNTs can further improve the mechanical properties and antibacterial properties of the material. The addition of modified MWCNTs can enhance the dispersion of PBrMAP-11 in the ABS matrix and reduce the agglomeration phenomenon, thus improving the antibacterial efficiency; while PBrMAP-11 can combine with nanoparticle templates (such as PLA, PEG or silica nanoparticles) to form a porous structure, further improving the heat insulation effect and mechanical properties of the material.

[0091] More specifically, in step S1, the plasticizer is phthalate esters, specifically dioctyl phthalate here, and this kind of plasticizer can effectively increase the flexibility and processability of the material.

[0092] The additives are calcium-zinc stabilizer and zinc stearate. Among them, the mass ratio of calcium-zinc stabilizer to zinc stearate in the additives is 2:3, which is used to improve the thermal stability and light stability of the material, prevent the material from decomposing under high temperature or light conditions, and can reduce the friction of the material during the processing, improving the processing efficiency and the surface quality of the material.

[0093] In step S1, the specific steps of mixing and preparation are as follows:

[0094] S14. Mix ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additives in a mass ratio of 60 - 70:12 - 15:3 - 7:2 - 3;

[0095] S15. Add the mixture of S14 into a twin-screw extruder, set the temperature at 200 - 210 °C, and the screw speed at 60 - 70 rpm, and carry out melt extrusion granulation to obtain the ABS antibacterial masterbatch of PBrMAP-n.

[0096] Specifically, the particle size range of the prepared ABS antibacterial masterbatch is 2 - 4 mm.

[0097] In step S2, the specific steps are as follows:

[0098] S21. After preparing the antibacterial masterbatch and ABS resin in a mass ratio of 4 - 6:28 - 32, carry out dry mixing at room temperature for 5 - 10 min to ensure that the antibacterial masterbatch is evenly dispersed in the ABS resin;

[0099] S22. Carry out melt blending of the materials mixed in S21 through a twin-screw extruder, and set the extruder temperature at 180 - 220 °C and the screw speed at 200 - 300 rpm;

[0100] S23. The melt-blended material is extruded through the die head of the extruder to form a strip. After the strip is cooled by a cooling water tank, it is cut into antibacterial mixed pellets with uniform particle size by a pelletizer.

[0101] Specifically, in step S21, the dry mixing is carried out using a high-speed mixer at 300 rpm for 10 minutes to ensure that all components are fully mixed.

[0102] In step S3, the specific steps of mixing and preparation are as follows:

[0103] S31. Pre-compound the nano-particle template and modified MWCNTs to obtain the template-MWCNTs material;

[0104] S32. Prepare the antibacterial mixed pellets obtained in step S2 and the SiO2-MWCNTs composite template according to a preset mass ratio;

[0105] S33. Add the materials prepared in S32 to a high-speed mixer and mix them at a rotation speed of 300 - 500 rpm for 5 - 10 min at room temperature to ensure that each component is evenly dispersed;

[0106] S34. Conduct melt blending on the mixed materials through a twin-screw extruder, with the extrusion temperature being 180 - 220 °C and the screw rotation speed being 200 - 300 rpm;

[0107] S35. Extrude the molten materials in S34 into strips through a die head, quickly cool and shape them through a cooling water tank, and cut the cooled strips into uniformly sized particles with a pelletizer to obtain the final antibacterial plastic pellets.

[0108] Specifically, in step S34, the twin-screw extruder includes a conveying section (low shear) → a mixing section (shear rate 500 s⁻¹) → a shearing section (1500 s⁻¹) → a forming section. When passing through the high-shear zone (1500 s⁻¹), the MWCNTs are oriented along the extrusion direction. The twin-screw extruder uses a slit die head (aspect ratio 20:1), and a torpedo head flow dividing device is set at the inlet to make the melt generate tensile flow, and the aspect ratio orientation degree of the MWCNTs is increased by more than 40%.

[0109] More specifically, during the melt blending process, through the flow field design of the twin-screw extruder and the optimization of the die channel, the MWCNTs are arranged along a specific direction. Parallel electrodes are set at the extrusion die head, and the charged MWCNTs are arranged along the electric field direction through the action of the electric field to further improve the orientation degree of the carbon nanotubes.

[0110] In step S31, the specific steps of pre-composite are as follows:

[0111] S311. Mix the modified SiO₂ nanoparticles, acid-treated MWCNTs (aspect ratio 100 - 196:1) and ethanol according to a mass ratio of 1 - 2:1 - 2:100 - 120;

[0112] S312. Conduct ultrasonic treatment (40 kHz, power 300 W) for 1 h. SiO₂ and MWCNTs are combined through the following actions:

[0113] KH570 on the surface of SiO₂ forms hydrogen bonds or ester bonds with -COOH of MWCNTs, and MWCNTs are interspersed in the porous structure of SiO₂;

[0114] S313. Centrifuge at 10000 - 12,000 rpm for 12 - 15 min to collect the composite, wash it 3 times with ethanol, and vacuum dry it at 50 - 60 °C for 11 - 12 h to obtain the SiO₂-MWCNTs composite template.

[0115] Such as Figure 2As shown, in step S3, the preparation steps of modified MWC1NTs are as follows:

[0116] S3111. Weigh MWCNTs and γ-methacryloxypropyltrimethoxysilane according to a mass ratio of 98 - 102:1 - 2.

[0117] S3112. Acidify MWCNTs.

[0118] S3113. Disperse the acidified MWCNTs.

[0119] S3114. Place the dispersed MWCNTs solution in an oil bath at 50 - 60 °C, add KH570, and react for 7 - 8 h.

[0120] S3115. Filter the MWCNTs after the treatment in S34, wash the filter residue three times with absolute ethanol, place the filter residue in a vacuum oven and dry it to constant weight to obtain MWCNTs. The obtained MWCNTs have a diameter of (10 - 20 nm).

[0121] The specific steps in step S3112 are as follows:

[0122] S31121. Add MWCNTs to the mixed acid solution and stir to obtain a mixture.

[0123] S31122. Ultrasonically treat the mixture at a frequency of 40 - 50 kHz and a power of 200 - 400 w for 1 - 2 h.

[0124] S31123. Dilute the ultrasonically treated mixture with water to neutral, centrifuge for 15 - 30 min (centrifuge speed is 10,000 rpm), discard the supernatant, and repeat centrifugal washing 2 - 3 times until there is no sulfate ion in the supernatant.

[0125] S31124. Precipitate the washed MWCNTs and dry them at 80 - 90 °C for 12 - 24 h to obtain acidified MWCNTs.

[0126] Among them, the mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid according to a volume ratio of 1 - 5:1; place the mixed concentrated sulfuric acid and concentrated nitric acid in an oil bath at 40 °C - 60 °C, turn on magnetic stirring, and continuously react at 500 rpm for 6 h. The centrifugation speed is 10,000 rpm to obtain.

[0127] Specifically, the ultrasonic treatment is specifically to transfer the mixture to an ultrasonic instrument and ultrasonically treat it at a frequency of 40 kHz for 1 h to further exfoliate the agglomerated MWCNTs and promote the acid etching effect.

[0128] More specifically,

[0129] Specifically, the strong oxidizing property of the mixed acid will cut off the longer tube segments in the MWCNTs, shortening their length, thereby reducing the aspect ratio (length / diameter). Reducing the aspect ratio can reduce the agglomeration tendency of MWCNTs in the ABS matrix while retaining their function of enhancing mechanical properties. This process can eliminate the entanglement of overly long carbon tubes and improve subsequent dispersibility. An overly high aspect ratio is likely to cause fiber entanglement during processing, while moderately reducing it can balance dispersibility and reinforcement effect, and the regulation of the aspect ratio is achieved by reducing the aspect ratio.

[0130] Acid etching introduces -COOH (carboxyl) and -OH (hydroxyl) functional groups on the surface of MWCNTs, enhancing their chemical bonding ability with the subsequent silane coupling agent (KH570) (step S314);

[0131] Acid treatment can dissolve the metal catalyst residues (such as Fe, Co) and amorphous carbon impurities in MWCNTs, improve purity, and reduce the influence of defects on the aspect ratio.

[0132] When the treatment time is short, the oxidation effect of the acidic solution on MWCNTs is insufficient, mainly concentrated on the introduction of surface functional groups. At this time, the length change of the carbon nanotubes is small and the aspect ratio is high. When the treatment time is long, the oxidation effect of the acidic solution is more profound, which can cut off the longer carbon nanotubes and shorten their length, resulting in a significant reduction in the aspect ratio.

[0133] In step S3, the preparation steps of the nanoparticle template are as follows:

[0134] S3116. Add tetraethyl orthosilicate (TEOS) to absolute ethanol according to a mass ratio of 1:10, stir magnetically (300 rpm, 10 min), slowly drop ammonia water (28%) and water according to a mass ratio of 3:10 to form a mixed solution, and keep stirring in a 40°C water bath for 6 h to generate SiO2 sol;

[0135] S3117. After the SiO2 sol reacts for 1 h, add γ-methacryloxypropyltrimethoxysilane (KH570) and continue stirring for 5 h;

[0136] S3118. Let the sol stand for 24 h to complete aging, and then dry it in an 80°C oven for 12 h to obtain surface-modified SiO2 gel;

[0137] S3119. Place the gel in a muffle furnace, heat it to 550°C at a rate of 2°C / min, and calcine it for 4 h to remove organic substances and obtain porous SiO2 nanoparticles.

[0138] The obtained SiO2 has a pore size of 10 - 30 nm.

[0139] Specifically, in step S317, grafting double bonds (-CH2=CH2) and methoxy groups (-OCH3) onto the surface of SiO2 can enhance the chemical bonding ability with MWCNTs and the ABS matrix.

[0140] Specifically, the pore diameter of SiO2 (10 - 30 nm) matches the diameter of MWCNTs (10 - 20 nm) to form an "nanotube - pore" interpenetrating structure, improving the load transfer efficiency; KH570 on the surface of SiO2 reacts with the -COOH groups of MWCNTs to form a stable interface, reducing stress concentration.

[0141] The template initially acts as a rigid support to enhance strength and gradually degrades to form pores in the later stage, and the MWCNTs network maintains the integrity of the material.

[0142] In step S32, the preset mass ratio is 90 - 95:5 - 10.

[0143] In step S4, the specific steps are as follows:

[0144] S41. Dry the antibacterial plastic pellets in a vacuum drying oven at 60 - 80 °C for 12 - 13 hours to remove moisture. After drying, seal the pellets to avoid moisture absorption.

[0145] S42. Add the dried antibacterial plastic pellets to the hopper of the molding press, install the mold on the molding press, set the mold temperature to 180 - 220 °C, start the molding press, press the pellets into the mold, apply a pressure of 10 - 20 MPa, and hold the pressure for 5 - 10 minutes to ensure that the material completely fills the mold and cures.

[0146] S43. Use a mold release agent or manual demolding to take out the molded ABS antibacterial plastic sheet from the mold.

[0147] Example 1

[0148] S1. Prepare an antibacterial masterbatch by mixing ABS resin, PBrMAP - 11 antibacterial agent, plasticizer, and additive in a mass ratio of 60 - 70:12 - 15:3 - 7:2 - 3.

[0149] S21. After preparing the antibacterial masterbatch and ABS resin in a mass ratio of 5:30, add them to a high - speed mixer and dry - mix at a speed of 300 rpm for 5 min at room temperature to ensure that the antibacterial masterbatch is evenly dispersed in the ABS resin.

[0150] S22. Melt - blend the mixture prepared in S21 through a twin - screw extruder. The temperature of the extruder is set at 180 - 220 °C, and the screw speed is 200 - 300 rpm.

[0151] S23. The material after melt blending is extruded through the die head of an extruder to form a strip. After the strip is cooled in a cooling water tank, it is cut into antibacterial mixed pellets with uniform particle size by a pelletizer.

[0152] S3. Add modified MWC1NTs and nanoparticle templates to the antibacterial mixed pellets, and mix and prepare to obtain antibacterial plastic pellets;

[0153] Among them, the preparation steps of the modified MWC1NTs are as follows:

[0154] S3111. Weigh MWCNTs and γ-methacryloxypropyltrimethoxysilane according to a mass ratio of 100:1;

[0155] S3112. Acid-treat the MWCNTs;

[0156] S31121. Add the original MWCNTs to the above mixed acid solution, place it in an oil bath at 60°C, turn on the magnetic stirrer, and continuously react at 500 rpm for 6 h to obtain a mixed solution;

[0157] S31122. Transfer the mixed solution to an ultrasonic instrument, and perform ultrasonic treatment at a frequency of 40 kHz for 1 h to further exfoliate the agglomerated MWCNTs and promote the acid etching effect;

[0158] S31123. Dilute the ultrasonically treated mixed solution with water to neutral (pH = 7), centrifuge it at 10,000 rpm for 15 min by a high-speed centrifuge, discard the supernatant, and repeat the centrifugation and washing 3 times until there are no sulfate ions in the supernatant;

[0159] S31124. Transfer the washed MWCNTs precipitate to a vacuum drying oven and dry it at 80°C for 12 h to obtain acidified MWCNTs.

[0160] S3113. Disperse the acid-treated MWCNTs;

[0161] S3114. Place the dispersed MWCNTs solution in step S33 in an oil bath at 60°C, add KH570, and react for 8 h;

[0162] S3115. Filter the MWCNTs after the treatment in S34, wash the filter residue three times with absolute ethanol, and place the filter residue in a vacuum oven to dry to constant weight to obtain modified MWCNTs.

[0163] Among them, the mixing and preparation steps in S3 are as follows:

[0164] S31. Pre-compound the nanoparticle template and the modified MWCNTs to obtain a template-MWCNTs material;

[0165] S32. Prepare the antibacterial mixed pellets obtained in step S2 and the SiO2-MWCNTs composite template according to a preset mass ratio;

[0166] S33. Add the materials prepared in S32 into a high-speed mixer, and mix at a speed of 300 rpm for 5 min at room temperature to ensure uniform dispersion of each component;

[0167] S34. Carry out melt blending on the mixed materials through a twin-screw extruder, with an extrusion temperature of 180 °C and a screw speed of 200 rpm;

[0168] S35. The melt material in S34 is extruded into strips through a die head, and is quickly cooled and shaped through a cooling water tank. The cooled strip is cut into particles with uniform particle size by a granulator to obtain the final antibacterial plastic pellets.

[0169] S41. Dry the antibacterial plastic pellets in a vacuum drying oven at 70 °C for 12 hours to remove moisture. The dried pellets are sealed and stored to avoid moisture absorption;

[0170] S42. Add the dried antibacterial plastic pellets into the hopper of a molding press, install the mold on the molding press, set the mold temperature to 180 °C, start the molding press, press the pellets into the mold, apply a pressure of 10 MPa, and hold the pressure for 5 minutes to ensure that the material completely fills the mold and cures;

[0171] S42. Use a mold release agent or manual demolding to take out the formed ABS antibacterial plastic plate from the mold.

[0172] Comparative Example 1

[0173] Difference: Modified MWCNTs are not used;

[0174] Comparative Example 2

[0175] Difference: Nanoparticle templates are not used;

[0176] Comparative Example 3

[0177] Difference: When preparing modified MWCNTs, the modified MWCNTs are not acid-treated;

[0178] Comparative Example 4

[0179] Difference: S31122. Add the original MWCNTs into the above mixed acid solution, place it in an oil bath at 60 °C, turn on the magnetic stirrer, and continuously react at 500 rpm for 3 h to obtain a mixed solution;

[0180] Among them, the mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid at a volume ratio of 3:1; the prepared concentrated sulfuric acid and concentrated nitric acid are placed in an oil bath at 50°C, magnetic stirring is started, and the reaction is continued at 500 rpm for 6 h. It is obtained by centrifugation at a speed of 10,000 rpm;

[0181] S31122. Ultrasonically treat the mixed solution at a frequency of 40 kHz and a power of 300 w for 1-2 h;

[0182] Comparative Example 5

[0183] The difference lies in S31122. Add the original MWCNTs to the above-mentioned mixed acid solution, place it in an oil bath at 60°C, start magnetic stirring, and continue the reaction at 500 rpm for 9 h to obtain a mixed solution;

[0184] Among them, the mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid at a volume ratio of 1:1; the prepared concentrated sulfuric acid and concentrated nitric acid are placed in an oil bath at 60°C, magnetic stirring is started, and the reaction is continued at 500 rpm for 6 h. It is obtained by centrifugation at a speed of 10,000 rpm;

[0185] S31122. Ultrasonically treat the mixed solution at a frequency of 40 kHz and a power of 400 w for 1-2 h;

[0186] Comparative Example 6

[0187] The difference lies in S21. After preparing the antibacterial masterbatch and ABS resin at a mass ratio of 5:28, dry-mix them at room temperature for 5-10 min to ensure that the antibacterial masterbatch is evenly dispersed in the ABS resin;

[0188] Comparative Example 7

[0189] The difference lies in S21. After preparing the antibacterial masterbatch and ABS resin at a mass ratio of 5:32, dry-mix them at room temperature for 5-10 min to ensure that the antibacterial masterbatch is evenly dispersed in the ABS resin.

[0190] Experimental Example 1

[0191] According to the ISO22196 standard, tests are carried out using Escherichia coli and Staphylococcus aureus.

[0192] Cut the sample into small pieces of 2 cm × 2 cm, put them into a petri dish containing a bacterial suspension of 10^6 CFU / mL, and culture at 37°C for 24 hours.

[0193] Use an ultraviolet spectrophotometer to measure the bacterial concentration and calculate the antibacterial rate.

[0194] Using the agar diffusion method, place the sample on an agar plate coated with bacteria and culture at 37°C for 24 hours.

[0195] Measure the diameter of the antibacterial zone, test 3 samples, and take the average value. As shown in Table 1;

[0196] Disperse the prepared MWCNTs in Examples 1 and Comparative Examples 1-7 on a silicon wafer to ensure that the sample surface is clean and the MWCNTs are evenly distributed.

[0197] Perform a metal coating treatment (using gold here) on the sample to improve conductivity and image quality, and use a scanning electron microscope (SEM) to observe and photograph the sample. Select an acceleration voltage of 10 kV and adjust the magnification to obtain a clear image.

[0198] Randomly select 99 MWCNTs from the SEM images, use image analysis software to measure the length and diameter of each MWCNT, and calculate the aspect ratio of each MWCNT using the aspect ratio calculation formula: aspect ratio = length / diameter. As shown in Table 1;

[0199] Table 1

[0200]

[0201] As can be seen from the data in Table 1, the antibacterial rate of Example 1 reached 95.1%, which is much higher than that of other comparative examples (80.2% for Comparative Example 1, 85.2% for Comparative Example 2, and 82.3% for Comparative Example 3), indicating that the addition of modified MWCNTs and nanoparticle templates significantly improved the antibacterial efficiency. The reasons are as follows: In Example 1, the phosphonium salt group (-P+) of the PBrMAP-11 antibacterial agent binds to the negatively charged group on the bacterial cell membrane through electrostatic interaction, destroying the integrity of the cell membrane. At the same time, the high specific surface area and surface functional groups of the modified MWCNTs enhance the dispersibility of the antibacterial agent, enabling it to act more evenly on the bacterial surface. In Comparative Examples 1-3, due to the lack of key components or treatment steps, the dispersibility of the antibacterial agent is poor and the antibacterial efficiency is low. In Example 1, the hydrophobic interaction between the alkyl side chain (11 carbon atoms) of PBrMAP-11 and the bacterial cell membrane enhances the penetration ability of the antibacterial agent, enabling it to more deeply destroy the bacterial cell membrane. At the same time, the porous structure of the nanoparticle template provides more release sites for the antibacterial agent, prolonging the antibacterial action time. In Comparative Examples 1-3, due to the lack of key components or treatment steps, there are insufficient release sites for the antibacterial agent, resulting in a smaller diameter of the antibacterial zone.

[0202] The antibacterial rate of Example 1 reached 95%, which was higher than that of Comparative Example 4 and Comparative Example 5. The reason is that in Example 1, the phosphonium salt group (-P+) of the PBrMAP-11 antibacterial agent binds to the negatively charged group on the bacterial cell membrane through electrostatic interaction, destroying the integrity of the cell membrane. At the same time, the high specific surface area and surface functional groups of the modified MWCNTs provide more adsorption sites for the antibacterial agent, enabling it to be evenly dispersed on the material surface and come into full contact with bacteria. In Comparative Example 4, due to the too high aspect ratio of MWCNTs, the agglomeration phenomenon led to uneven dispersion of the antibacterial agent, and the concentration of the antibacterial agent in some areas was too low to effectively inhibit the growth of bacteria. In Comparative Example 5, the aspect ratio was slightly lower, the adsorption sites of MWCNTs were slightly fewer, the dispersibility of the antibacterial agent was slightly worse, and the antibacterial rate was slightly lower. In Example 1, the hydrophobic interaction between the alkyl side chain (11 carbon atoms) of PBrMAP-11 and the bacterial cell membrane enhanced the penetration ability of the antibacterial agent. At the same time, the aspect ratio of MWCNTs was about 196:1, forming a uniform antibacterial agent release channel, enabling the antibacterial agent to be continuously and stably released, and expanding the antibacterial range. In Comparative Example 4, due to the too high aspect ratio of MWCNTs, the release channels were uneven, the release rate of the antibacterial agent was inconsistent, and the diameter of the antibacterial circle was small. In Comparative Example 5, the aspect ratio was slightly lower, the release channel was slightly narrower, the release rate of the antibacterial agent was slightly slower, and the diameter of the antibacterial circle was slightly smaller.

[0203] The antibacterial rate and the diameter of the antibacterial circle of Example 1 were both greater than those of Comparative Example 6 and Comparative Example 7. The reason is that: the tensile strength, flexural strength and impact strength of Example 1 were all greater than those of Comparative Examples 6-7. By adjusting the ratio of the antibacterial masterbatch to the ABS resin, the distribution of the antibacterial agent was gradually optimized, enabling it to act more evenly on the surface of bacteria. MWCNTs provided more adsorption sites and enhanced the penetration ability of the antibacterial agent, thereby improving the antibacterial efficiency; when adding the ABS resin for the second time, more ABS resin further enhanced the intermolecular interaction. The gradual addition of the ABS resin made the combination between MWCNTs and the matrix closer, improved the cohesion of the material, and further optimized the distribution of MWCNTs, making the stress transfer network more uniform and effective. Moreover, more ABS resin further diluted the concentration of the antibacterial agent while ensuring its uniform distribution. In Comparative Example 6, the proportion of the antibacterial masterbatch was relatively high (5:28), resulting in too high a concentration of the antibacterial agent, causing agglomeration, affecting its uniform dispersion in the matrix, and the phosphonium salt group (-P +)Although it can bind to the negatively charged groups on the bacterial cell membrane through electrostatic interactions, due to the aggregation of the antibacterial agent, some antibacterial agents cannot effectively contact the bacterial cell membrane, resulting in a decrease in antibacterial efficiency. A smaller inhibition zone diameter indicates that the release behavior of the antibacterial agent is uneven, with too high a concentration of the antibacterial agent in some areas and too low a concentration in other areas, making it unable to effectively inhibit bacterial growth; in Comparative Example 7, the proportion of the antibacterial masterbatch is relatively low (5:32), and the low concentration of the antibacterial agent is not sufficient to cover all the negatively charged groups on the bacterial cell membrane, affecting the antibacterial efficiency. The alkyl side chain of PBrMAP-11 (11 carbon atoms) weakens the hydrophobic interaction with the bacterial cell membrane, resulting in a decrease in the penetration ability of the antibacterial agent. A smaller inhibition zone diameter indicates that the release behavior of the antibacterial agent is uneven, with too low a concentration of the antibacterial agent in some areas, making it unable to effectively inhibit bacterial growth.

[0204] Experimental Example 2

[0205] Tensile strength: Tested using a universal material testing machine according to ISO527 standard;

[0206] Flexural strength: Tested using a universal material testing machine according to ISO178 standard;

[0207] Impact strength: Tested using an impact testing machine according to ISO180 standard;

[0208] For the above three tests, tensile specimens of standard size were prepared, 5 samples were tested, and the average value was taken. As shown in Table 2;

[0209] Disperse the prepared MWCNTs in Examples 1 and Comparative Examples 1-7 on a silicon wafer to ensure that the sample surface is clean and the MWCNTs are evenly distributed.

[0210] Perform metal coating treatment (using gold here) on the sample to improve conductivity and image quality, and observe and photograph the sample using a scanning electron microscope (SEM). Select an acceleration voltage of 10 kV and adjust the magnification to obtain a clear image.

[0211] Randomly select 99 MWCNTs from the SEM images, use image analysis software to measure the length and diameter of each MWCNT, and calculate the aspect ratio of each MWCNT using the aspect ratio calculation formula, aspect ratio = length / diameter. As shown in Table 2;

[0212] Table 2

[0213]

[0214]

[0215] According to the data in Table 2, the tensile strength of Example 1 reached 55.2 MPa, which was significantly higher than that of Comparative Example 1 (45.3 MPa), Comparative Example 2 (50.2 MPa), and Comparative Example 3 (48.4 MPa). This indicates that the addition of modified MWCNTs and the nanoparticle template significantly improved the tensile strength of the material. The reason is that in Example 1, the carboxyl (-COOH) and hydroxyl (-OH) functional groups on the surface of the modified MWCNTs formed strong intermolecular interactions (such as hydrogen bonds) with the ABS matrix, enhancing the cohesion of the material. In addition, the porous structure of the nanoparticle template provided an additional mechanical anchoring effect, further improving the tensile strength. In Comparative Example 1, there was a lack of modified MWCNTs; in Comparative Example 2, the nanoparticle template was missing; and in Comparative Example 3, no acid treatment was carried out, resulting in insufficient intermolecular interactions and mechanical anchoring effects, and thus lower tensile strength. The high modulus and rigid structure of the modified MWCNTs formed an effective stress transfer network in the matrix, while the porous structure of the nanoparticle template dispersed the stress concentration points, jointly improving the flexural strength of the material. In Comparative Examples 1 - 3, due to the lack of key components or processing steps, the stress transfer network was imperfect and there were more stress concentration points, resulting in lower flexural strength. In Example 1, the synergistic effect of the modified MWCNTs and the nanoparticle template formed a multi-scale reinforcement network inside the material, which could effectively absorb and disperse the impact energy, thereby improving the impact strength. In Comparative Examples 1 - 3, due to the lack of key components or processing steps, the ability to absorb and disperse the impact energy was insufficient, resulting in lower impact strength.

[0216] The tensile strength of Example 1 reached 55 MPa, which was significantly higher than that of Comparative Example 4 (52.5 MPa) and Comparative Example 5 (53.6 MPa). In Example 1, the MWCNTs with an aspect ratio of about 196:1 formed the best intermolecular interactions with the ABS matrix, ensuring both good dispersibility and sufficient reinforcement effect. In Example 1, the aspect ratio of the MWCNTs was about 196:1, forming a uniform stress transfer network, effectively dispersing the stress concentration points, and forming a multi-scale reinforcement network, which could effectively absorb and disperse the impact energy. In Comparative Example 4 (aspect ratio 152:1) and Comparative Example 5 (aspect ratio 98:1), the MWCNTs had a deviation in aspect ratio from the optimal range, resulting in a slight decrease in intermolecular interactions and reinforcement effect.

[0217] The tensile strength, flexural strength, and impact strength of Example 1 are all greater than those of Comparative Examples 6-7. The reasons are as follows: By adjusting the ratio of the antibacterial masterbatch to the ABS resin, the distribution of MWCNTs in the matrix is optimized, forming a uniform stress transfer network. The MWCNTs with an optimized aspect ratio can transfer stress more effectively and disperse stress concentration points, thus significantly improving the mechanical properties of the material. The ratio of Example 1 (5:30) achieves the best balance between antibacterial performance and mechanical properties. When adding ABS resin for the second time, more ABS resin further enhances the intermolecular interaction. The gradual addition of ABS resin makes the combination between MWCNTs and the matrix closer, improves the cohesion of the material, and further optimizes the distribution of MWCNTs, making the stress transfer network more uniform and effective. Moreover, more ABS resin further dilutes the concentration of the antibacterial agent and ensures its uniform distribution. In Comparative Example 6 of Example 1, the ratio of the antibacterial masterbatch is relatively high (5:28), resulting in a decrease in the cohesion of the matrix. The high concentration of the antibacterial agent interferes with the orderly arrangement of molecular chains in the ABS matrix, leading to a weakening of intermolecular interactions (such as hydrogen bonds). The number of hydrogen bonds formed between the carboxyl groups (-COOH) and hydroxyl groups (-OH) on the surface of the modified MWCNTs and the polar groups (nitrile groups) in the ABS matrix decreases, resulting in a decrease in cohesion. The stress transfer network formed by the high modulus and rigid structure of MWCNTs in the matrix is not uniform enough, resulting in stress concentration in some areas and affecting the mechanical properties. In Comparative Example 7, the ratio of the antibacterial masterbatch is relatively low (5:32), resulting in too low a concentration of the antibacterial agent. The low concentration of the antibacterial agent cannot fully interact with the functional groups on the surface of MWCNTs, affecting the enhancement effect. The intermolecular interaction (such as hydrogen bonds) between the modified MWCNTs and the ABS matrix is insufficient, resulting in a decrease in cohesion. The mechanical anchoring effect provided by the porous structure of the nanoparticle template is insufficient, resulting in a poor stress dispersion effect and affecting the mechanical properties.

[0218] Based on the inspiration of the ideal embodiments of the present invention, through the above description, relevant personnel can make various changes and modifications completely within the scope of not deviating from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A preparation process of ABS antibacterial plastic board, characterized in that: include: S1. Mix ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive in a mass ratio of 60-70:12-15:3-7:2-3 to obtain an antibacterial masterbatch; S2, mixing the antibacterial masterbatch and ABS resin in a mass ratio of 4-6:28-32 to obtain an antibacterial mixed granular material; S3, adding modified MWC1NTs and nanoparticle templates into the antibacterial mixed granules, mixing and preparing, and obtaining antibacterial plastic granules; S4, compression molding the antibacterial plastic pellets to obtain an ABS antibacterial plastic plate.

2. The preparation process of an ABS antibacterial plastic plate according to claim 1, characterized in that: In step S1, the preparation steps of the PBrMAP-11 antibacterial agent are as follows: S11, preparing a bromoalkyl methacrylate intermediate; S12, synthesizing methacryloyloxyalkyltriphenylphosphonium bromide antibacterial monomer through the intermediate of S11; S13. Synthesize polymethacryloyloxyalkyltriphenylphosphonium bromide polymer antibacterial agent through the antibacterial monomer of S12.

3. The preparation process of an ABS antibacterial plastic plate according to claim 1, characterized in that: In step S1, the specific steps of mixing and preparing are: S14, mixing ABS resin, PBrMAP-11 antibacterial agent, plasticizer and additive in a mass ratio of 60-70:12-15:3-7:2-3; S15. Add the mixture of S14 into a twin-screw extruder, set the temperature to 200-210° C., and the screw speed to 60-70 rpm, and perform melt extrusion granulation to obtain ABS antibacterial masterbatch of PBrMAP-n.

4. The preparation process of an ABS antibacterial plastic plate according to claim 1, characterized in that: In step S2, the specific steps are: S21, preparing the antibacterial masterbatch and ABS resin in a mass ratio of 4-6:28-32, and dry mixing them at room temperature for 5-10 minutes; S22, melt blending the materials mixed in S21 through a twin-screw extruder, with the extruder temperature set at 180-220° C. and the screw speed at 200-300 rpm; S23, the melt-blended material is extruded through the die head of an extruder to form a strip, and the strip is cooled in a cooling water tank and then cut into antibacterial mixed pellets with uniform particle size by a pelletizer.

5. The process for preparing an ABS antibacterial plastic plate according to claim 1, characterized in that: In step S3, the specific steps of mixing and preparing are: S31, pre-compounding the nanoparticle template and modified MWCNTs to obtain a template-MWCNTs material; S32, preparing the antibacterial mixed granules and SiO2-MWCNTs composite template obtained in step S2 according to a preset mass ratio; S33, mixing the materials prepared in S32 for 5-10 minutes to ensure that the components are evenly dispersed; S34, melt blending the mixed materials through a twin-screw extruder, the extrusion temperature is 180-220° C., and the screw speed is 200-300 rpm; The molten materials of S35 and S34 are extruded into strips through a die head, and are rapidly cooled and shaped through a cooling water tank. The cooled strips are cut into particles with uniform particle sizes by a pelletizer to obtain the final antibacterial plastic pellets.

6. The process for preparing an ABS antibacterial plastic plate according to claim 5, characterized in that: In step S31, the specific steps of pre-compounding are: S311, mixing the modified SiO2 nanoparticles, the acidified MWCNTs and ethanol in a mass ratio of 1-2:1-2:100-120; S312, mixing by S311 and then ultrasonically treating for 1-2h; S313. Collect the complex by centrifugation at 10,000-12,000 rpm for 12-15 min, wash with ethanol three times, and vacuum dry at 50-60° C. for 11-12 h to obtain a SiO2-MWCNTs composite template.

7. The process for preparing an ABS antibacterial plastic plate according to claim 6, characterized in that: In step S3, the preparation steps of modified MWC1NTs are: S3111, weighing MWCNTs and γ-methacryloxypropyltrimethoxysilane in a mass ratio of 98-102:1-2; S3112, subjecting the MWCNTs to acid treatment; S3113, dispersing the MWCNTs after the acid treatment; S3114, placing the MWCNTs solution dispersed in S33 in a 50-60°C oil bath, adding KH570, and reacting for 7-8h; S3115. Filter the MWCNTs treated in S34, wash the filter residue three times with anhydrous ethanol, and dry the filter residue in a vacuum oven to constant weight to obtain modified MWCNTs.

8. The process for preparing an ABS antibacterial plastic plate according to claim 7, characterized in that: In step S3112, the specific steps are: S31121, adding MWCNTs to the mixed acid solution and stirring to obtain a mixed solution; S31122, ultrasonically treat the mixture at a frequency of 40-50kHz and a power of 200-400w for 1-2h; S31123, dilute the mixed solution after ultrasonic treatment with deionized water to neutrality, centrifuge for 15-30 minutes, discard the supernatant, repeat the centrifugation and washing 2-3 times until the supernatant is free of sulfate ions; S31124. Precipitate the washed MWCNTs and dry them at 80-90° C. for 12-24 h to obtain MWCNTs.

9. The process for preparing an ABS antibacterial plastic plate according to claim 5, characterized in that: In step S32, the preset mass ratio is 90-95:5-10.

10. The process for preparing an ABS antibacterial plastic plate according to claim 1, characterized in that: In step S4, the specific steps are: S41, drying the antibacterial plastic pellets in a vacuum drying oven at 60-80°C for 12-13 hours to remove moisture, and storing the dried pellets in a sealed container to prevent moisture absorption; S42, adding the dried antibacterial plastic pellets into the hopper of the molding machine, installing the mold on the molding machine, setting the mold temperature to 180-220° C., starting the molding machine, pressing the pellets into the mold, applying a pressure of 10-20 MPa, and maintaining the pressure for 5-10 minutes to ensure that the material completely fills the mold and solidifies; S43, using a release agent or manual demoulding, the molded ABS antibacterial plastic plate is removed from the mold.

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