Wear-resistant antibacterial plastic with self-cleaning function and preparation method thereof

Abstract

This invention belongs to the field of functional polymer materials technology, and provides a wear-resistant and antibacterial plastic with self-cleaning function and its preparation method. The plastic comprises a thermoplastic resin matrix, a phenylboronic acid-functionalized polysiloxane containing catechol groups, metal ion / plant polyphenol complexed antibacterial microparticles, a compatibilizer, and processing aids. This invention utilizes the dynamic covalent bonds of phenylboronic acid and catechol to construct a "self-layering" system, allowing the polysiloxane segments of the phenylboronic acid-functionalized polysiloxane containing catechol groups to spontaneously and directionally accumulate on the surface to form a durable hydrophobic self-cleaning layer. Simultaneously, the metal ion / plant polyphenol complexed antibacterial microparticles are covalently anchored in this layer, achieving long-lasting immobilized antibacterial properties and surface self-lubrication and wear resistance. After surface wear, the lower layer of phenylboronic acid-functionalized polysiloxane containing catechol groups can migrate and repair itself, endowing the material with renewable self-cleaning and antibacterial dual functions. This plastic does not rely on fluorinated compounds, has a simple preparation process, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of functional polymer materials technology, and in particular to a wear-resistant and antibacterial plastic with self-cleaning function and its preparation method. Background Technology

[0002] Plastics with multiple functions such as self-cleaning, wear resistance, and antibacterial properties are in high demand in fields such as medical device housings, household appliance panels, food contact products, and public transportation facilities. However, existing technologies typically use single-function additives to function independently. When multiple functions need to be achieved simultaneously, it is often necessary to add a variety of different functional fillers or additives. This leads to problems such as poor compatibility between components, mutual interference between functions, and deterioration of mechanical properties.

[0003] Regarding self-cleaning functionality, existing technologies mainly rely on two approaches: one is to coat the plastic surface with a hydrophobic coating, but this coating is prone to wear and peeling during use, resulting in poor durability; the other is to dope the plastic matrix with low surface energy substances (such as fluoropolymers, organosilicon, etc.), which maintain hydrophobicity through their migration to the surface. However, the continuous migration of low surface energy substances can lead to microporous defects inside the material, reducing mechanical properties, and the self-cleaning durability is limited by the total amount of additives, making it a "consumable" self-cleaning method.

[0004] In terms of wear-resistant modification, existing technologies mostly employ the addition of inorganic rigid particles (such as molybdenum disulfide, graphite, and carbon fiber) or organosilicon lubricants (such as silicone masterbatches). The ultra-high molecular weight polysiloxanes in silicone masterbatches migrate to the surface during processing and service to form a lubricating film, reducing the coefficient of friction. However, this migration also faces the problem of "depletion," making it difficult to guarantee long-term wear resistance.

[0005] In terms of antibacterial function, existing technologies mainly follow two routes: inorganic antibacterial agents (such as silver ions and zinc oxide) and organic antibacterial agents (such as quaternary ammonium salts and guanidines). Inorganic antibacterial agents have poor interfacial compatibility with polymer matrices, are prone to aggregation leading to low antibacterial efficiency and decreased mechanical properties; organic small-molecule antibacterial agents, on the other hand, pose a risk of exudation and migration, which not only causes a continuous decline in antibacterial activity but may also pose safety hazards to the human body. In recent years, some studies have grafted quaternary ammonium salt compounds onto the surface of nano-zinc oxide to improve dispersibility and long-lasting effect, but the binding mode of quaternary ammonium salts containing siloxane groups with zinc oxide means that the materials still mainly rely on the contact bactericidal mechanism of quaternary ammonium salt cations.

[0006] More importantly, existing technologies, when pursuing the triple functions of self-cleaning, wear resistance, and antibacterial properties simultaneously, often employ a simple "adding bricks and tiles" strategy—adding hydrophobic agents, lubricating and wear-resistant agents, and antibacterial agents separately to the matrix. There is a lack of synergistic effect between the functional components, and they may even antagonize each other: for example, the migration of hydrophobic agents to the surface can carry away some antibacterial agents, leading to the loss of antibacterial components; while adding a large amount of inorganic fillers to improve wear resistance will increase the hydrophilicity of the material surface and change the surface roughness, weakening the self-cleaning effect. In summary, there is currently no plastic composition solution that can simultaneously achieve durable self-cleaning, long-lasting wear resistance, and stable antibacterial properties at the material design level, with positive synergy rather than antagonism between the functions. Constructing a novel plastic system with chemical bonds between functional components, self-layering migration and recyclability, and integrated wear resistance, self-cleaning, and antibacterial properties has become a technological direction urgently needed for breakthroughs in this field. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wear-resistant and antibacterial plastic with self-cleaning function and its preparation method. This plastic can achieve long-lasting self-cleaning, wear resistance and antibacterial triple functions without relying on the continuous migration and consumption of external coatings and functional additives. The three functions have a synergistic effect mechanism at the molecular level, and the preparation process is simple and suitable for industrial production.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a wear-resistant and antibacterial plastic with self-cleaning function, comprising the following raw materials in parts by weight: 60-85 parts of thermoplastic resin matrix, 8-25 parts of phenylboronic acid functionalized polysiloxane containing catechol groups, 3-15 parts of metal ion / plant polyphenol complexed antibacterial microparticles, 1-5 parts of compatibilizer, and 0.5-3 parts of processing aid. The main molecular chain of the phenylboronic acid functionalized polysiloxane containing catechol groups is a polydimethylsiloxane segment, and the side chains and / or end groups are covalently connected to bifunctional aromatic segments containing catechol groups and phenylboronic acid groups, with a number average molecular weight of 2000~15000. The metal ion / plant polyphenol complexed antibacterial microparticles are formed by the coordination complexation of plant polyphenols and transition metal ions. The plant polyphenols are selected from one or more of tannic acid, epigallocatechin gallate, and tea polyphenol extract; the transition metal ions are selected from one or more of copper ions, zinc ions, and iron ions; the molar ratio of metal ions to phenolic hydroxyl groups in plant polyphenols is 1:2~5.

[0009] Furthermore, the thermoplastic resin matrix includes one or more of polypropylene, polyethylene, polystyrene, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polyethylene terephthalate, polyamide, and polylactic acid.

[0010] Furthermore, in the phenylboronic acid functionalized polysiloxane containing catechol groups, the molar ratio of catechol groups to phenylboronic acid groups is 1:0.8~1.2.

[0011] Furthermore, the metal ion / plant polyphenol complexed antibacterial microparticles are amorphous nanoaggregates with an average particle size of 50~500nm.

[0012] Furthermore, the compatibilizer includes one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, styrene-maleic anhydride copolymer, and epoxy-functionalized polyolefin.

[0013] Furthermore, the processing aid includes an antioxidant and a lubricant, wherein the antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants; and the lubricant includes calcium stearate, zinc stearate, or polyethylene wax.

[0014] This invention also provides a method for preparing the above-mentioned wear-resistant and antibacterial plastic with self-cleaning function, comprising the following steps: S1. After mixing plant polyphenol solution and transition metal salt solution, the mixture is reacted. After the reaction is completed, the mixture is centrifuged, washed, dried and ground in sequence to obtain metal ion / plant polyphenol complexed antibacterial microparticles. S2. A premix is ​​obtained by mixing a thermoplastic resin matrix, a phenylboronic acid functionalized polysiloxane containing catechol groups, metal ion / plant polyphenol complexed antibacterial microparticles, a compatibilizer, and a processing aid. S3. The premixed material is sequentially melt-blended, extruded, cooled, pelletized, and annealed to obtain a wear-resistant and antibacterial plastic with self-cleaning function.

[0015] Furthermore, in step S1, the concentration of the plant polyphenol solution is 5~30 mg / mL; The reaction temperature is 20~60℃, and the reaction time is 0.5~4h.

[0016] Furthermore, in step S2, the mixing speed is 200~800 rpm, and the mixing time is 5~15 min.

[0017] Furthermore, in step S3, the annealing temperature is 60~110℃, and the annealing time is 0.5~6h.

[0018] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows: 1. Durable and Renewable Self-Cleaning Function: Unlike existing technologies that rely on the continuous migration and consumption of hydrophobic additives, this invention utilizes the self-stratification of phenylboronic acid-functionalized polysiloxane (CAT-BA-PDMS) containing catechol groups to form a hydrophobic segment-rich layer on the surface. Once the surface is worn, the lower CAT-BA-PDMS layer can spontaneously migrate back to the new surface under thermodynamic drive to repair itself, achieving durable self-cleaning. The surface water contact angle can reach 105°~130°.

[0019] 2. Long-lasting and stable antibacterial function: The antibacterial microparticles are anchored in the self-layered hydrophobic layer by dynamic covalent bonds, and do not undergo exudation loss over time, thus having long-lasting antibacterial activity.

[0020] 3. Excellent wear resistance: Antibacterial microparticles act as physical cross-linking nodes to enhance the cross-linking density of the surface layer. At the same time, the PDMS segments themselves have a low coefficient of friction and self-lubricating effect. The two work together to give the material excellent wear resistance.

[0021] 4. Synergistic Effect of Three Functions: It is not a simple superposition of functions. The three functions establish a synergistic relationship at the molecular level through dynamic covalent self-layering and coordination complexation cross-linking. The self-cleaning function originates from the hydrophobic PDMS layer formed by self-layering, which also serves as a wear-resistant self-lubricating layer and antibacterial microparticle carrier. The antibacterial microparticles, in turn, enhance the mechanical strength of the surface layer and endow the surface with hydrophilic microdomains to achieve the anti-biofilm function. The wear resistance is achieved synergistically through hydrophobic self-lubrication and cross-linking enhancement.

[0022] 5. Simple process suitable for mass production: All functional components can be processed into shape in one step through conventional blending and melt extrusion, without the need for subsequent coating or post-processing steps, making it suitable for continuous industrial production.

[0023] 6. Not dependent on fluorinated compounds: The low surface energy function comes from PDMS segments and does not contain perfluorinated or polyfluoroalkyl substances (PFAS), making it environmentally friendly. Detailed Implementation

[0024] This invention provides a wear-resistant and antibacterial plastic with self-cleaning function, comprising the following raw materials in parts by weight: The thermoplastic resin matrix consists of 60-85 parts, phenylboronic acid functionalized polysiloxane containing catechol groups of 8-25 parts, metal ion / plant polyphenol complexed antibacterial microparticles of 3-15 parts, compatibilizer of 1-5 parts, and processing aid of 0.5-3 parts.

[0025] In this invention, the amount of thermoplastic resin matrix is ​​preferably 65-80 parts, and more preferably 70-75 parts.

[0026] In this invention, the amount of phenylboronic acid functionalized polysiloxane containing catechol groups is preferably 10 to 20 parts, and more preferably 15 parts.

[0027] In this invention, the amount of metal ion / plant polyphenol complexed antibacterial microparticles is preferably 5 to 10 parts, and more preferably 6 to 8 parts.

[0028] In this invention, the amount of compatibilizer is preferably 2 to 4 parts, and more preferably 3 parts.

[0029] In this invention, the preferred dosage of the processing aid is 1 to 2 parts, which is 0.5 to 3 parts.

[0030] In this invention, the main molecular chain of the phenylboronic acid functionalized polysiloxane containing catechol groups is a polydimethylsiloxane segment, and the side chains and / or end groups are covalently connected to bifunctional aromatic segments containing catechol groups and phenylboronic acid groups, with a number average molecular weight of 2000~15000. The metal ion / plant polyphenol complexed antibacterial microparticles are formed by the coordination complexation of plant polyphenols and transition metal ions. The plant polyphenols are selected from one or more of tannic acid, epigallocatechin gallate, and tea polyphenol extract. The transition metal ions are selected from one or more of copper ions, zinc ions, and iron ions. The molar ratio of metal ions to phenolic hydroxyl groups in plant polyphenols is 1:2 to 5, preferably 1:3 to 4.

[0031] In this invention, the thermoplastic resin matrix includes one or more of polypropylene, polyethylene, polystyrene, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polyethylene terephthalate, polyamide, and polylactic acid.

[0032] In this invention, the molar ratio of catechol groups to phenylboronic acid groups in the phenylboronic acid functionalized polysiloxane containing catechol groups is 1:0.8~1.2, preferably 1:1.

[0033] In this invention, the metal ion / plant polyphenol complexed antibacterial microparticles are amorphous nanoaggregates with an average particle size of 50~500nm.

[0034] In this invention, the compatibilizer includes one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, styrene-maleic anhydride copolymer, and epoxy-functionalized polyolefin.

[0035] In this invention, the processing aid comprises an antioxidant and a lubricant. The antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants; the lubricant includes calcium stearate, zinc stearate, or polyethylene wax.

[0036] This invention also provides a method for preparing the above-mentioned wear-resistant and antibacterial plastic with self-cleaning function, comprising the following steps: S1. After mixing plant polyphenol solution and transition metal salt solution, the mixture is reacted. After the reaction is completed, the mixture is centrifuged, washed, dried and ground in sequence to obtain metal ion / plant polyphenol complexed antibacterial microparticles. S2. A premix is ​​obtained by mixing a thermoplastic resin matrix, a phenylboronic acid functionalized polysiloxane containing catechol groups, metal ion / plant polyphenol complexed antibacterial microparticles, a compatibilizer, and a processing aid. S3. The premixed material is sequentially melt-blended, extruded, cooled, pelletized, and annealed to obtain a wear-resistant and antibacterial plastic with self-cleaning function.

[0037] In this invention, in step S1, the concentration of the plant polyphenol solution is 5~30 mg / mL, preferably 10~25 mg / mL, and more preferably 15~20 mg / mL; The reaction temperature is 20~60℃, preferably 30~50℃, and more preferably 40℃; the reaction time is 0.5~4h, preferably 1~3h, and more preferably 2h.

[0038] In this invention, in step S2, the mixing speed is 200~800 rpm, preferably 500 rpm; the mixing time is 5~15 min, preferably 10 min.

[0039] In this invention, in step S3, the annealing temperature is 60~110℃, preferably 80~100℃; the annealing time is 0.5~6h, preferably 1~5h, and more preferably 2~4h.

[0040] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0041] The preparation method of phenylboronic acid-functionalized polysiloxanes containing catechol groups is as follows: Under nitrogen protection, 4-carboxyphenylboronic acid (1.66 g, 10 mmol) and dopamine hydrochloride (1.90 g, 10 mmol) were dissolved in 30 mL of anhydrous DMF, and EDC·HCl (2.30 g, 12 mmol) and NHS (1.38 g, 12 mmol) were added. The mixture was stirred at room temperature for 18 h. The reaction solution was poured into excess deionized water to precipitate the precipitate, which was collected, washed three times with deionized water, and dried under vacuum at 40 °C to obtain the CAT-BA intermediate (white to light gray powder, yield approximately 78%). The above CAT-BA intermediate (2.5 g) was dissolved in 20 mL of anhydrous toluene, mixed with hydrogen-containing silicone oil (0.18 wt% hydrogen, approximately 6000 Mn, 15 g) and a caster catalyst (3 ppm Pt), and stirred at 90 °C for 6 h under nitrogen protection. Toluene and unreacted small molecules were removed by vacuum distillation to obtain a light yellow viscous liquid phenylboronic acid-functionalized polysiloxane (CAT-BA-PDMS) containing catechol groups (number average molecular weight 7200, molar ratio of catechol groups to phenylboronic acid groups approximately 1:0.95).

[0042] Example 1 Dissolve 5.0 g of tannic acid in 300 mL of deionized water and adjust the pH to 9.0 with 1 mol / L NaOH solution. Slowly add 50 mL of a 0.2 mol / L copper sulfate (CuSO4·5H2O) aqueous solution (CuSO4·5H2O) while stirring. 2+ The reaction mixture was stirred at 25°C for 2 hours (molar ratio of pyrogallol group to tannic acid was 1:3). The reaction mixture was centrifuged at 10,000 rpm for 15 minutes. The precipitate was washed twice with deionized water and twice with anhydrous ethanol. It was then dried under vacuum at 50°C for 24 hours and ground to obtain a dark brown flocculent powder (copper-tannic acid complex microparticles with an average particle size of 200 nm).

[0043] 70 parts of polypropylene resin (PP, melt index 10 g / 10 min), 15 parts of CAT-BA-PDMS, 10 parts of copper-tannic acid complex microparticles, 3 parts of maleic anhydride grafted polypropylene (PP-g-MAH), 0.5 parts of antioxidant 1010, and 1 part of calcium stearate were added to a high-speed mixer and mixed at 800 rpm for 10 min to obtain a premix.

[0044] The premixed material was fed into a co-rotating twin-screw extruder, with the following temperature settings for each zone: Zone 1 160℃, Zone 2 180℃, Zone 3 200℃, Zone 4 200℃, Zone 5 195℃, and Die Head 190℃. The screw speed was 250 rpm. The extrudate was water-cooled and pelletized. The resulting pellets were then injection molded into standard test specimens at an injection temperature of 200℃ and a die temperature of 40℃. After injection molding, the specimens were annealed at 80℃ for 2 hours to obtain a wear-resistant and antibacterial plastic with self-cleaning properties.

[0045] Example 2 Dissolve 5.0 g of tannic acid in 300 mL of deionized water and adjust the pH to 9.0 with 1 mol / L NaOH solution. Slowly add 50 mL of 0.2 mol / L copper sulfate (CuSO₄) while stirring. 4· 5H2O) aqueous solution (Cu 2+ The reaction mixture was stirred at 25°C for 2 hours (molar ratio of pyrogallol group to tannic acid was 1:3). The reaction mixture was centrifuged at 10,000 rpm for 15 minutes. The precipitate was washed twice with deionized water and twice with anhydrous ethanol. It was then dried under vacuum at 50°C for 24 hours and ground to obtain a dark brown flocculent powder (copper-tannic acid complex microparticles with an average particle size of 200 nm).

[0046] 70 parts of polypropylene resin (PP, melt index 10 g / 10 min), 20 parts of CAT-BA-PDMS, 5 parts of copper-tannic acid complex microparticles, 3 parts of maleic anhydride grafted polypropylene (PP-g-MAH), 0.5 parts of antioxidant 1010, and 1 part of calcium stearate were added to a high-speed mixer and mixed at 800 rpm for 10 min to obtain a premix.

[0047] The premixed material was fed into a co-rotating twin-screw extruder, with the following temperature settings for each zone: Zone 1 160℃, Zone 2 180℃, Zone 3 200℃, Zone 4 200℃, Zone 5 195℃, and Die Head 190℃. The screw speed was 250 rpm. The extrudate was water-cooled and pelletized. The resulting pellets were then injection molded into standard test specimens at an injection temperature of 200℃ and a die temperature of 40℃. After injection molding, the specimens were annealed at 80℃ for 2 hours to obtain a wear-resistant and antibacterial plastic with self-cleaning properties.

[0048] Example 3 Dissolve 5.0 g of tea polyphenols in 300 mL of deionized water, and adjust the pH to 9.0 with 1 mol / L NaOH solution. Slowly add 50 mL of 0.2 mol / L zinc chloride (ZnCl2) aqueous solution (Zn) while stirring. 2+ The reaction mixture was stirred at 25°C for 2 hours (molar ratio of pyrogallol groups in tannic acid to 1:3). The reaction solution was centrifuged at 10,000 rpm for 15 minutes. The precipitate was washed twice with deionized water and twice with anhydrous ethanol, dried under vacuum at 50°C for 24 hours, and then ground to obtain zinc-tea polyphenol complexed antibacterial microparticles.

[0049] 70 parts of polypropylene resin (PP, melt index 10 g / 10 min), 20 parts of CAT-BA-PDMS, 5 parts of zinc-tea polyphenol complexed antibacterial microparticles, 3 parts of maleic anhydride grafted polypropylene (PP-g-MAH), 0.5 parts of antioxidant 1010, and 1 part of calcium stearate were added to a high-speed mixer and mixed at 800 rpm for 10 min to obtain a premix.

[0050] The premixed material was fed into a co-rotating twin-screw extruder, with the following temperature settings for each zone: Zone 1 160℃, Zone 2 180℃, Zone 3 200℃, Zone 4 200℃, Zone 5 195℃, and Die Head 190℃. The screw speed was 250 rpm. The extrudate was water-cooled and pelletized. The resulting pellets were then injection molded into standard test specimens at an injection temperature of 200℃ and a die temperature of 40℃. After injection molding, the specimens were annealed at 80℃ for 2 hours to obtain a wear-resistant and antibacterial plastic with self-cleaning properties.

[0051] Example 4 Tannic acid (5.0 g) was dissolved in 300 mL of deionized water, and the pH was adjusted to 9.0 with 1 mol / L NaOH solution. 50 mL of a 0.2 mol / L copper sulfate (CuSO4·5H2O) aqueous solution (the molar ratio of Cu2+ to the pyrogallol group in tannic acid was 1:3) was slowly added dropwise while stirring. The reaction mixture was stirred at 25 °C for 2 h. The reaction solution was centrifuged at 10,000 rpm for 15 min. The precipitate was washed twice with deionized water and twice with anhydrous ethanol, dried under vacuum at 50 °C for 24 h, and ground to obtain a dark brown flocculent powder (copper-tannic acid complexed microparticles, average particle size 200 nm).

[0052] 70 parts of ABS resin, 15 parts of CAT-BA-PDMS, 10 parts of copper-tannic acid complex microparticles, 3 parts of maleic anhydride grafted polypropylene (PP-g-MAH), 0.5 parts of antioxidant 1010, and 1 part of calcium stearate were added to a high-speed mixer and mixed at 800 rpm for 10 minutes to obtain a premix.

[0053] The premixed material was fed into a co-rotating twin-screw extruder, with the following temperature settings for each zone: Zone 1 180℃, Zone 2 190℃, Zone 3 200℃, Zone 4 220℃, Zone 5 210℃, and Die Head 200℃. The screw speed was 250 rpm. The extrudate was water-cooled and pelletized. The resulting pellets were then injection molded into standard test specimens at an injection temperature of 200℃ and a die temperature of 40℃. After injection molding, the specimens were annealed at 80℃ for 2 hours to obtain a wear-resistant and antibacterial plastic with self-cleaning properties.

[0054] Comparative Example 1 Without the addition of CAT-BA-PDMS and metal ion / plant polyphenol complexed antibacterial microparticles, the rest is the same as in Example 1.

[0055] Comparative Example 2 Replace CAT-BA-PDMS with an equal amount of polydimethylsiloxane, and the rest is the same as in Example 1.

[0056] Comparative Example 3 The copper-tannic acid complexed microparticles were replaced with an equal amount of zinc oxide, and the rest was the same as in Example 1.

[0057] Performance testing 1. Water Contact Angle (WCA): A contact angle meter was used, with a deionized water droplet volume of 5 μL. Five points were tested for each sample, and the average value was taken. The higher the water contact angle, the better the surface's hydrophobic self-cleaning performance.

[0058] 2. Taber wear resistance: According to ASTM D4060 standard, CS-10 grinding wheel, load 1000g, 500 revolutions, the wear amount (mg) was measured.

[0059] 3. Antibacterial properties: According to GB / T 31402-2015 standard, Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were used as test bacteria, and the antibacterial rate (%) was calculated. Simultaneously, a wash resistance durability test was conducted—the antibacterial rate was retested after the sample was immersed in deionized water at 25℃ for 72 hours.

[0060] 4. Dynamic friction coefficient: The steady-state friction coefficient was measured after 1,000 cycles using a friction and wear testing machine with stainless steel dual balls, a load of 5N, a sliding speed of 5mm / s.

[0061] The test results for all the above tests are shown in Table 1 below.

[0062] Table 1 Performance Test Results

[0063] As shown in Table 1, Example 1 exhibits comprehensive performance improvements: a water contact angle of 118°, abrasion loss of only 12.4 mg, antibacterial rates against both Escherichia coli and Staphylococcus aureus exceeding 99%, and an antibacterial rate remaining at 99.3% after 72 hours of washing. The dynamic coefficient of friction is only 0.21. Compared to Comparative Example 1, abrasion loss is reduced by approximately 65%, and the antibacterial rate is increased by more than an order of magnitude.

[0064] Comparative Example 2 used ordinary PDMS without phenylboronic acid / catechol groups instead of CAT-BA-PDMS. Although the water contact angle was considerable, the antibacterial rate dropped significantly, especially after washing, the antibacterial rate was only 35.4%, indicating that dynamic covalent bond anchoring is crucial for antibacterial durability.

[0065] Comparative Example 3 used commercially available nano zinc oxide to replace the complexed antibacterial microparticles. Although the initial antibacterial rate could reach over 95%, it dropped to 71.5% after 72 hours of water washing, proving that the antibacterial filler without internal anchoring would gradually be lost during use.

[0066] In Example 2, after increasing the amount of CAT-BA-PDMS to 20 parts, the water contact angle was further increased to 125° and the coefficient of friction was reduced to 0.18. However, the antibacterial performance decreased slightly due to the reduced amount of antibacterial microparticles. After washing, the antibacterial rate was 95.4%, which still met the practical requirements.

[0067] The solutions in Example 3, which used zinc-tea polyphenol complexed microparticles, and in Example 4, which used an ABS matrix, also exhibited excellent overall performance, proving that the technical solutions of the present invention are applicable to a variety of thermoplastic resin matrices and a variety of plant polyphenol / metal ion combinations.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wear-resistant and antibacterial plastic with self-cleaning function, characterized in that, Including the following parts by weight of raw materials: 60-85 parts of thermoplastic resin matrix, 8-25 parts of phenylboronic acid functionalized polysiloxane containing catechol groups, 3-15 parts of metal ion / plant polyphenol complexed antibacterial microparticles, 1-5 parts of compatibilizer, and 0.5-3 parts of processing aid. The main molecular chain of the phenylboronic acid functionalized polysiloxane containing catechol groups is a polydimethylsiloxane segment, and the side chains and / or end groups are covalently connected to bifunctional aromatic segments containing catechol groups and phenylboronic acid groups, with a number average molecular weight of 2000~15000. The metal ion / plant polyphenol complexed antibacterial microparticles are formed by the coordination complexation of plant polyphenols and transition metal ions. The plant polyphenols are selected from one or more of tannic acid, epigallocatechin gallate, and tea polyphenol extract; the transition metal ions are selected from one or more of copper ions, zinc ions, and iron ions; the molar ratio of metal ions to phenolic hydroxyl groups in plant polyphenols is 1:2~5.

2. The wear-resistant and antibacterial plastic with self-cleaning function according to claim 1, characterized in that, The thermoplastic resin matrix includes one or more of polypropylene, polyethylene, polystyrene, acrylonitrile-butadiene-styrene copolymer, polycarbonate, polyethylene terephthalate, polyamide, and polylactic acid.

3. The wear-resistant and antibacterial plastic with self-cleaning function according to claim 2, characterized in that, In the phenylboronic acid functionalized polysiloxane containing catechol groups, the molar ratio of catechol groups to phenylboronic acid groups is 1:0.8~1.

2.

4. The wear-resistant and antibacterial plastic with self-cleaning function according to claim 2 or 3, characterized in that, The metal ion / plant polyphenol complexed antibacterial microparticles are amorphous nanoaggregates with an average particle size of 50~500nm.

5. The wear-resistant and antibacterial plastic with self-cleaning function according to claim 4, characterized in that, The compatibilizer includes one or more of maleic anhydride-grafted polypropylene, maleic anhydride-grafted polyethylene, styrene-maleic anhydride copolymer, and epoxy-functionalized polyolefin.

6. The wear-resistant and antibacterial plastic with self-cleaning function according to claim 2, 3 or 5, characterized in that, The processing aids include antioxidants and lubricants. The antioxidants include at least one of hindered phenolic antioxidants and phosphite antioxidants. The lubricants include calcium stearate, zinc stearate, or polyethylene wax.

7. A method for preparing the wear-resistant and antibacterial plastic with self-cleaning function according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. After mixing plant polyphenol solution and transition metal salt solution, the mixture is reacted. After the reaction is completed, the mixture is centrifuged, washed, dried and ground in sequence to obtain metal ion / plant polyphenol complexed antibacterial microparticles. S2. A premix is ​​obtained by mixing a thermoplastic resin matrix, a phenylboronic acid functionalized polysiloxane containing catechol groups, metal ion / plant polyphenol complexed antibacterial microparticles, a compatibilizer, and a processing aid. S3. The premixed material is sequentially melt-blended, extruded, cooled, pelletized, and annealed to obtain a wear-resistant and antibacterial plastic with self-cleaning function.

8. The preparation method according to claim 7, characterized in that, In step S1, the concentration of the plant polyphenol solution is 5~30 mg / mL; The reaction temperature is 20~60℃, and the reaction time is 0.5~4h.

9. The preparation method according to claim 8, characterized in that, In step S2, the mixing speed is 200~800 rpm and the mixing time is 5~15 min.

10. The preparation method according to any one of claims 7 to 9, characterized in that, In step S3, the annealing temperature is 60~110℃ and the annealing time is 0.5~6h.

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