Preparation method and application of antibacterial coating based on polyvinyl chloride plastic

Abstract

The invention belongs to the technical field of functional polymer materials and photocatalysis, and particularly relates to a preparation method and application of an antibacterial coating based on polyvinyl chloride plastics. Comprising the following steps: S1, pretreatment; s2, carrying out a reaction; s3, post-processing is carried out; s4, compounding with polyelectrolyte; and S5, preparing the coating. Through a specific catalytic cracking process, the waste PVC is converted into a functional photocatalytic antibacterial coating material, so that resource utilization and functional utilization of the waste chlorine-containing plastic are realized; a catalytic cracking process under a solvent-free condition is adopted, so that the use of an organic solvent is avoided; the coating material has relatively good photochemical stability, and can realize a relatively lasting antibacterial effect; the method has relatively low requirements on equipment, reaction conditions are easy to control, and the method is not only suitable for laboratory research, but also convenient for engineering and industrial amplification. And by combining the processing performance of the obtained coating, the technology has popularization and application potential.

Description

Technical Field

[0001] This invention relates to the fields of functional polymer materials and photocatalysis technology, specifically to a method for preparing an antibacterial coating based on polyvinyl chloride plastic and its application. Background Technology

[0002] With the continuous advancement of industrialization and urbanization, coating materials have been widely used in various fields such as construction, transportation, electronics, power, packaging, medical, and daily necessities to impart protective, corrosion-resistant, wear-resistant, antibacterial, or functional modifier properties to substrates. Existing coating materials primarily utilize petroleum-based synthetic polymers as their film-forming substances. While these materials typically exhibit good film-forming properties and stability, their preparation process relies on fossil resources, resulting in high overall energy consumption. Furthermore, their production and use often involve organic solvents or complex chemical synthesis steps, posing a certain environmental burden. In addition, some coating materials are difficult to effectively recycle and reuse after their service life, further exacerbating resource consumption and solid waste disposal pressures.

[0003] Polyvinyl chloride (PVC), one of the five major general-purpose plastics, ranks only after polyethylene (PE) and polypropylene (PP) in terms of production volume and is widely used in construction, pipes, cables, and packaging. However, due to the large amount of chlorine in the PVC molecular chain, its disposal and resource utilization after waste collection face severe environmental challenges. Currently, PVC recycling mainly includes mechanical recycling and thermochemical recycling. During mechanical recycling, the polymer molecular chain is prone to breakage, leading to a significant decline in material properties, thus limiting its regeneration applications in high-value-added fields. Although thermochemical recycling can recover energy or some chemicals, it easily releases toxic and corrosive gases such as hydrogen chloride during the process, and its overall energy utilization efficiency is low. Therefore, the recycling rate of waste PVC is still low at present, and a large amount of waste PVC is ultimately disposed of through landfill or incineration, resulting in resource waste and potential environmental risks. How to achieve high-value and functional utilization of waste PVC has become an important issue that urgently needs to be addressed in the field of plastic pollution control.

[0004] Photocatalysis, as a green technology that utilizes solar energy to drive chemical reactions, has shown promising application prospects in environmental governance and energy conversion, especially in the in-situ synthesis of hydrogen peroxide from water and oxygen. Hydrogen peroxide, as an environmentally friendly oxidant, has significant application value in antibacterial disinfection and environmental purification. However, existing high-performance organic photocatalytic materials typically rely on sophisticated organic synthesis, which involves complex preparation processes, high raw material costs, and difficulties in large-scale, low-cost production, severely hindering their widespread adoption in practical applications such as functional coatings.

[0005] Against this backdrop, utilizing widely available, inexpensive waste plastics, especially waste PVC, rich in carbon skeleton structures as precursors to construct photoresponsive functional materials could not only significantly reduce the preparation cost of photocatalytic materials but also provide new solutions for the resource utilization and high-value-added use of waste plastics. However, current technologies lack a method that can effectively utilize the molecular structural characteristics of PVC through relatively simple chemical means to transform it into a functional coating material possessing both photocatalytic activity and antibacterial properties. Therefore, how to solve the environmental pollution problem of waste PVC while achieving its low-cost transformation into high-value-added photocatalytic antibacterial coating materials remains a critical technical challenge that urgently needs to be overcome in the fields of photocatalytic materials and environmental functional coatings. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution: A method for preparing an antibacterial coating based on polyvinyl chloride plastic includes the following steps: S1: Pretreatment: Mix polyvinyl chloride plastic and catalyst thoroughly and evenly; S2: Reaction: The mixture obtained in S1 reacts under certain conditions; S3: Post-processing: After the reaction is completed, the DCPVC material is obtained by quenching, washing, filtration and drying. S4: Polyelectrolyte composite: DCPVC material is mixed evenly with aqueous solutions of polyelectrolytes carrying positive and negative charges respectively to obtain stable suspensions of two polyelectrolyte composites; S5: Coating preparation: The above two polyelectrolyte composite stable suspensions are sequentially deposited onto the surface of the substrate material and dried to obtain the coating material.

[0008] As a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the polyvinyl chloride plastic in S1 is pure polyvinyl chloride plastic or post-consumer waste polyvinyl chloride plastic products, including powder, film, and pipe; the catalyst used includes one or more combinations of AlCl3, FeCl3, ZnCl2, TiCl4, BF3, and Al2O3 and ZnO.

[0009] In a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the ratio of catalyst to polyvinyl chloride plastic in S1 is 0.01:1-10:1.

[0010] As a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the reaction in S2 includes heating, ultrasonication, manual grinding, and mechanical ball milling.

[0011] As a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the heating temperature is 40-260 ℃ and the heating time is 0.25-4 h; the ultrasonic time is 0.25-10 h; and the mechanical ball milling or manual grinding time is 0.25-10 h.

[0012] In a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic as described in this invention, anhydrous ethanol is used for quenching in step S3; the cleaning operation specifically involves first cleaning with pure water, then cleaning with ethanol, and finally filtration using a vacuum pump.

[0013] In a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the concentrations of the positively charged polyelectrolyte aqueous solution and the negatively charged polyelectrolyte aqueous solution in step S4 are controlled at 0.01-10 mol / L.

[0014] As a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, in step S5, the stable suspension of the polyelectrolyte complex is deposited onto the surface of the substrate material by means of casting, spin coating, or spraying. During deposition, the first layer must be completely dry before the second layer is deposited, and so on, for a total of 2-10 layers.

[0015] As a preferred embodiment of the method for preparing an antibacterial coating based on polyvinyl chloride plastic according to the present invention, the obtained DCPVC material exhibits photocatalytic activity in generating H2O2 from water and air under natural sunlight, and can also effectively photosynthesize H2O2 in seawater or aqueous solutions with certain acidity or alkalinity.

[0016] The present invention also provides the application of a composite coating of DCPVC and polyelectrolyte prepared according to the preparation method described above in antibacterial materials.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. Achieving high-value utilization of waste polyvinyl chloride (PVC) plastics. This invention utilizes a specific catalytic cracking process to transform waste PVC into a functional photocatalytic antibacterial coating material, realizing the resource and functional utilization of waste chlorinated plastics, which helps reduce the environmental burden and improve the utilization efficiency of carbon resources.

[0018] 2. The process is relatively environmentally friendly and cost-effective. This invention employs a solvent-free catalytic cracking process, avoiding the use of organic solvents and thus reducing environmental risks and subsequent treatment burdens. Furthermore, using widely available waste plastics as raw materials offers significant advantages in terms of raw material costs and preparation complexity compared to traditional photocatalytic materials synthesized using precious metals or complex organic monomers.

[0019] 3. Stable photocatalytic performance and sustained antibacterial effect. The coating material in this invention has good photochemical stability, which enables a relatively long-lasting antibacterial effect and reduces the need for frequent replacement or maintenance.

[0020] 4. Excellent environmental adaptability and application scalability. The coating material prepared by the method of this invention exhibits good stability under different environmental conditions and can maintain its photoresponse characteristics under certain acidic, alkaline, and saline conditions. This characteristic makes it suitable not only for conventional antibacterial coating applications but also for applications in complex aquatic environments or special working conditions.

[0021] 5. The preparation method is simple and has good prospects for industrial application. The method described in this invention has relatively low equipment requirements, and the reaction conditions are easy to control. It is suitable for laboratory research and also easy to scale up for engineering and industrial applications. Considering the processing performance of the obtained coating, this technology has the potential for widespread application. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a diagram showing the photocatalytic activity of the coating material prepared in Example 1 of this invention under outdoor sunlight. Figure 2 This is a macroscopic effect diagram of the coating prepared in Example 1 of the present invention; Figure 3 The image shows the antibacterial properties of the coating prepared in Example 1 of this invention against Escherichia coli and Staphylococcus aureus. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0026] This invention provides a method for preparing an antibacterial coating based on polyvinyl chloride plastic, comprising the following steps: S1: Pretreatment: The polyvinyl chloride (PVC) plastic and the catalyst are thoroughly mixed. The PVC plastic is pure PVC plastic or post-consumer waste PVC plastic products, including powder, film, and pipe. The catalyst used includes one or more combinations of AlCl3, FeCl3, ZnCl2, TiCl4, BF3, Al2O3, and ZnO. The ratio of catalyst to PVC plastic is 0.01:1-10:1. S2: Reaction: The mixture obtained in S1 is reacted under certain conditions. The reaction methods include heating, ultrasound, manual grinding, and mechanical ball milling. The heating temperature is 40-260 ℃ and the heating time is 0.25-4 h; the ultrasound time is 0.25-10 h; the mechanical ball milling or manual grinding time is 0.25-10 h. S3: Post-processing: After the reaction is completed, DCPVC material is obtained by quenching, washing, filtration and drying. Quenching is performed using anhydrous ethanol. The washing operation is as follows: first wash with pure water, then wash with ethanol, and then filter using a vacuum pump. S4: Polyelectrolyte composite: DCPVC material is mixed evenly with positively and negatively charged polyelectrolyte aqueous solutions to obtain two stable suspensions of polyelectrolyte composites. The concentrations of the positively charged and negatively charged polyelectrolyte aqueous solutions are controlled at 0.01-10 mol / L. S5: Coating preparation: The two polyelectrolyte composite stable suspensions mentioned above are sequentially deposited onto the surface of the substrate material. After drying, the coating material is obtained. The polyelectrolyte composite stable suspensions are deposited onto the surface of the substrate material by casting, spin coating, or spraying. During deposition, the first layer must be completely dry before the second layer is deposited. A total of 2-10 layers are deposited in sequence. The obtained DCPVC material exhibits photocatalytic activity in generating H2O2 from water and air under natural sunlight, and can also effectively photosynthesize H2O2 in seawater or aqueous solutions with certain acidity or alkalinity.

[0027] A method for preparing an antibacterial coating based on polyvinyl chloride plastic has been developed. The composite coating of DCPVC and polyelectrolyte prepared by this method has a significant bactericidal effect on both Escherichia coli and Staphylococcus aureus in antibacterial materials.

[0028] Specifically, a method for preparing an antibacterial coating based on polyvinyl chloride plastic: Example 1, the catalyst is AlCl 3， Its preparation method is as follows: Step 1: Weigh 0.5 g of PVC powder and 0.0107 g of AlCl3 granules into a round-bottom flask and mix them thoroughly. Step 2: Place the round-bottom flask containing the above powder in an oil bath and heat at 260 °C for 15 min. Step 3: After the reaction is completed, cool to room temperature, quench with ethanol, and then wash with large amounts of deionized water and ethanol in sequence. Dry the resulting solid powder at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 1 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 1 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 0.5 g of DCPVC and add it to 100 mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes; Step 6: Drop the DCPVC and PDDA mixture onto a glass slide. After it is completely dry, drop the DCPVC and PSS mixture onto its surface. After it is completely dry, repeat the above operation. Apply a total of 4 layers. After it is completely dry again, wash with deionized water and dry to obtain a photocatalytic antibacterial coating.

[0029] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0030] Example 2, the catalyst used is FeCl₂ 3， Its preparation method is as follows: Step 1: Weigh 0.5 g of PVC powder and 12.96 g of FeCl3 powder into a round-bottom flask and mix them thoroughly. Step 2: Place the round-bottom flask containing the above powder in an oil bath and heat at 40 °C for 4 h. Step 3: After the reaction is completed, cool to room temperature, quench with ethanol, and then wash with large amounts of deionized water and ethanol in sequence. Dry the resulting solid powder at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 1 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 1 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 0.5 g of DCPVC and add it to 100 mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes; Step 6: Spray the DCPVC and PDDA mixture onto the glass slide. After it is completely dry, spray the DCPVC and PSS mixture onto its surface. After it is completely dry, repeat the above operation. Apply a total of 10 layers. After it is completely dry again, wash with deionized water and dry to obtain a photocatalytic antibacterial coating.

[0031] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0032] Example 3, the catalyst is ZnO and FeCl 3， Its preparation method is as follows: Step 1: Weigh 0.5 g of PVC pipe fragments, 2.61 g of ZnO powder, and 0.0648 g of FeCl3 powder into a mortar and mix them evenly. Step 2: Place the above powder in a mortar and grind manually for 8 hours; Step 3: After the reaction is complete, the reaction is quenched with ethanol, and then washed with a large amount of deionized water and ethanol in sequence. The resulting solid powder is dried at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 1 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 1 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 0.2g of DCPVC and add it to 100mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes; Step 6: Spin-coat the DCPVC and PDDA mixture onto a glass slide, smooth it out, and after it is completely dry, spin-coat the DCPVC and PSS mixture onto its surface, smooth it out again, and repeat the above operation after it is completely dry. Coat a total of 6 layers. After it is completely dry again, wash it with deionized water and dry it to obtain a photocatalytic antibacterial coating.

[0033] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm (e.g. Figure 2 (As shown).

[0034] Example 4: The catalyst is ZnCl2, and its preparation method is as follows: Step 1: Weigh 0.5 g of PVC film fragments and 1.088 g of ZnCl2 powder into a ball mill jar and mix them evenly; Step 2: Place the ball mill jar containing the above powder into a ball mill and ball mill for 15 minutes; Step 3: After the reaction is complete, the reaction is quenched with ethanol, and then washed with a large amount of deionized water and ethanol in sequence. The resulting solid powder is dried at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 5 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 5 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 0.5g of DCPVC and add it to 100mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes. Step 6: Apply the DCPVC and PDDA mixture onto a glass slide, smooth it out, and after it is completely dry, apply the DCPVC and PSS mixture onto its surface, smooth it out again, and after it is completely dry again, wash it with deionized water and dry it to obtain a photocatalytic antibacterial coating.

[0035] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0036] Example 5 uses Al2O3 and AlCl3 as catalysts, and its preparation method is as follows: Step 1: Weigh 0.5 g of PVC powder, 2.45 g of Al2O3 powder, and 0.109 g of AlCl3 powder into a ball mill jar and mix them evenly. Step 2: Place the ball mill jar containing the above powder into a ball mill and ball mill for 8 hours; Step 3: After the reaction is complete, the reaction is quenched with ethanol, and then washed with a large amount of deionized water and ethanol in sequence. The resulting solid powder is dried at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 10 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 10 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 1 g of DCPVC and add it to 100 mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes. Step 6: Spray the DCPVC and PDDA mixture onto the glass slide. After it is completely dry, spray the DCPVC and PSS mixture onto its surface. After it is completely dry, repeat the above operation for a total of 4 layers. After it is completely dry again, wash with deionized water and dry to obtain a photocatalytic antibacterial coating.

[0037] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0038] Example 6: The catalyst is TiCl4, and its preparation method is as follows: Step 1: Weigh 1 g of PVC powder and 1.517 g of TiCl4 powder into a round-bottom flask and mix them thoroughly. Step 2: Place the round-bottom flask containing the above powder into an ultrasonic cleaner and sonicate for 15 minutes. Step 3: After the reaction is complete, the reaction is quenched with ethanol, and then washed with a large amount of deionized water and ethanol in sequence. The resulting solid powder is dried at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare a 5 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 10 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 2 g of DCPVC and add it to 100 mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes. Step 6: Spray the DCPVC and PDDA mixture onto the glass slide. After it is completely dry, spray the DCPVC and PSS mixture onto its surface. After it is completely dry again, wash it with deionized water and dry it to obtain a photocatalytic antibacterial coating.

[0039] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0040] Example 7: The catalyst is BF3, and its preparation method is as follows: Step 1: Weigh 0.5 g of PVC powder and 1.085 g of BF3 powder into a mortar and mix them evenly. Step 2: Place the powder in a mortar and grind manually for 15 minutes; Step 3: After the reaction is complete, the reaction is quenched with ethanol, and then washed with a large amount of deionized water and ethanol in sequence. The resulting solid powder is dried at 60 °C for 24 h to obtain the photocatalyst DCPVC material. Step 4: Prepare an 8 mol / L aqueous solution of polydiallyldimethylammonium chloride (PDDA) and a 10 mol / L aqueous solution of sodium polystyrene sulfonate (PSS); Step 5: Take 1 g of DCPVC and add it to 100 mL of the above PDDA and PSS aqueous solutions to obtain two stable suspensions of polyelectrolyte complexes. Step 6: Spray the DCPVC and PDDA mixture onto the glass slide. After it is completely dry, spray the DCPVC and PSS mixture onto its surface. After it is completely dry, repeat the above operation for a total of 8 layers. After it is completely dry again, wash with deionized water and dry to obtain a photocatalytic antibacterial coating.

[0041] The photocatalytic antibacterial coating prepared in step 6 has a smooth surface, and the laboratory scale has been scaled up to 40*36cm.

[0042] experiment The following experiments were conducted using the materials obtained in the above embodiments: Experiment 1 The purpose of this experiment is to study the photocatalytic hydrogen peroxide production performance of the obtained catalyst under outdoor sunlight.

[0043] Experiment 1-1 Please see Figure 1 100 mg of the photocatalyst material obtained in Example 1 was added to 200 mL of deionized water and placed in a petri dish to uniformly disperse the catalyst on the surface of the aqueous solution. At 9:00 AM, the petri dish was placed outdoors under sunlight to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and at 4:00 PM, the concentration of hydrogen peroxide in the aqueous solution reached 323.14 μmol / L.

[0044] Experiment 1-2 100 mg of the photocatalyst material obtained in Example 2 was added to 200 mL of deionized water and placed in a petri dish to uniformly disperse the catalyst on the surface of the aqueous solution. At 9:00 AM, the petri dish was placed outdoors under sunlight to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and at 4:00 PM, the concentration of hydrogen peroxide in the aqueous solution reached 315.79 μmol / L.

[0045] Experiments 1-3 100 mg of the photocatalyst material obtained in Example 3 was added to 200 mL of deionized water and placed in a petri dish to uniformly disperse the catalyst on the surface of the aqueous solution. At 9:00 AM, the petri dish was placed outdoors under sunlight to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and at 4:00 PM, the concentration of hydrogen peroxide in the aqueous solution reached 264.11 μmol / L.

[0046] Experiments 1-4 100 mg of the photocatalyst material obtained in Example 4 was added to 200 mL of deionized water and placed in a petri dish to uniformly disperse the catalyst on the surface of the aqueous solution. At 9:00 AM, the petri dish was placed outdoors in sunlight to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and at 4:00 PM, the concentration of hydrogen peroxide in the aqueous solution reached 355.74 μmol / L.

[0047] Experiments 1-5 100 mg of the photocatalyst material obtained in Example 5 was added to a petri dish along with 200 mL of deionized water to ensure uniform dispersion of the catalyst on the surface of the aqueous solution. The petri dish was placed outdoors in sunlight at 9:00 AM to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and reached 239.51 μmol / L at 4:00 PM.

[0048] Experiments 1-6 100 mg of the photocatalyst material obtained in Example 6 was added to 200 mL of deionized water and placed in a petri dish to uniformly disperse the catalyst on the surface of the aqueous solution. At 9:00 AM, the petri dish was placed outdoors under sunlight to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and at 4:00 PM, the concentration of hydrogen peroxide in the aqueous solution reached 284.72 μmol / L.

[0049] Experiments 1-7 100 mg of the photocatalyst material obtained in Example 7 was added to a petri dish along with 200 mL of deionized water to ensure uniform dispersion of the catalyst on the surface of the aqueous solution. The petri dish was placed outdoors in sunlight at 9:00 AM to allow the reaction to proceed. The concentration of hydrogen peroxide in the aqueous solution was measured hourly, and reached 344.29 μmol / L at 4:00 PM.

[0050] Experiment 2 The purpose of this experiment is to study the inhibitory effect of the obtained photocatalyst coating on Escherichia coli.

[0051] Experiment 2-1 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 1 and immersed in 10... 6The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was counted using a colony counting method. The results showed that 100% of *E. coli* were killed. Please refer to [link / reference]. Figure 3 Comparison of Escherichia coli before and after photoreaction using coating material for 2 hours (Figures a and b).

[0052] Experiment 2-2 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 2 and immersed in 10... 6 The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 97% of the E. coli were killed.

[0053] Experiment 2-3 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 3 and immersed in 10... 6 The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 94% of the E. coli were killed.

[0054] Experiment 2-4 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 4 and immersed in 10... 6 The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 93% of the E. coli were killed.

[0055] Experiment 2-5 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 5 and immersed in 10... 6The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 97% of the E. coli were killed.

[0056] Experiment 2-6 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 6 and immersed in 10... 6 The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 98% of the E. coli were killed.

[0057] Experiment 2-7 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 7 and immersed in 10... 6 The solution was prepared in CFU / mL *E. coli* and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto an LB agar plate. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 95% of the E. coli were killed.

[0058] Experiment 3 The purpose of this experiment is to study the inhibitory effect of the obtained photocatalyst coating on Staphylococcus aureus.

[0059] Experiment 3-1 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 1 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using a colony count method. The results showed that 100% of Staphylococcus aureus was killed. Please refer to [link / reference needed]. Figure 3 Comparison of Staphylococcus aureus before and after photoreaction with the coating material for 2 hours (Figures c and d).

[0060] Experiment 3-2 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 2 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 96% of Staphylococcus aureus were killed.

[0061] Experiment 3-3 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 3 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 91% of Staphylococcus aureus were killed.

[0062] Experiment 3-4 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 4 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 94% of Staphylococcus aureus were killed.

[0063] Experiment 3-5 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 5 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 96% of Staphylococcus aureus were killed.

[0064] Experiment 3-6 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 6 and immersed in 10...6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 96% of Staphylococcus aureus were killed.

[0065] Experiment 3-7 A 1*3cm sample was cut from the photocatalyst coating obtained in Example 7 and immersed in 10... 6 The solution was infused with CFU / mL Staphylococcus aureus and then placed under a 400-800 nm white LED light source for photocatalytic reaction. After 2 hours, 200 μL of the mixture was pipetted, diluted with PBS, and 100 μL was evenly spread onto LB agar plates. The mixture was then incubated for 37 hours. o After overnight incubation at C, the number of surviving bacteria was calculated using colony counting. The results showed that 95% of Staphylococcus aureus were killed.

[0066] In summary, this invention provides an innovative pathway for converting waste polyvinyl chloride (PVC) plastic into a high-value-added photocatalytic antibacterial coating material. This technical solution not only achieves the resource utilization of waste plastics through a low-cost, solvent-free preparation process, providing a new solution for sustainable waste management; but also produces coating materials with excellent environmental adaptability and broad-spectrum antibacterial properties, demonstrating significant industrial application potential in areas such as indoor curtains, green building exterior wall protection, and antifouling of marine facilities (e.g., ship hulls).

[0067] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing an antibacterial coating based on polyvinyl chloride plastic, characterized in that, Includes the following steps: S1: Pretreatment: Mix polyvinyl chloride plastic and catalyst thoroughly and evenly; S2: Reaction: The mixture obtained in S1 reacts under certain conditions; S3: Post-processing: After the reaction is completed, the DCPVC material is obtained by quenching, washing, filtration and drying. S4: Polyelectrolyte composite: DCPVC material is mixed evenly with aqueous solutions of polyelectrolytes carrying positive and negative charges respectively to obtain stable suspensions of two polyelectrolyte composites; S5: Coating preparation: The above two polyelectrolyte composite stable suspensions are sequentially deposited onto the surface of the substrate material and dried to obtain the coating material.

2. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, The polyvinyl chloride plastic in S1 is pure polyvinyl chloride plastic or post-consumer waste polyvinyl chloride plastic products, including powder, film, and pipe; the catalyst used includes one or more combinations of AlCl3, FeCl3, ZnCl2, TiCl4, BF3, Al2O3, and ZnO.

3. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, The ratio of catalyst to polyvinyl chloride plastic in S1 is 0.01:1 to 10:

1.

4. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 2, characterized in that, The reaction methods in S2 include heating, ultrasound, manual grinding, and mechanical ball milling.

5. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 2, characterized in that, The heating temperature is 40-260 ℃, and the heating time is 0.25-4 h; the ultrasonic time is 0.25-10 h; the mechanical ball milling or manual grinding time is 0.25-10 h.

6. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, In step S3, anhydrous ethanol is used for quenching; the cleaning operation specifically involves first cleaning with pure water, then cleaning with ethanol, and finally using a vacuum pump for filtration.

7. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, The concentrations of the positively charged and negatively charged polyelectrolyte aqueous solutions in S4 are controlled between 0.01 and 10 mol / L.

8. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, The polyelectrolyte complex stabilized suspension in S5 is deposited onto the surface of the substrate material by casting, spin coating, or spraying. During deposition, the first layer must be completely dry before the second layer is deposited, and so on, for a total of 2-10 layers.

9. The method for preparing an antibacterial coating based on polyvinyl chloride plastic according to claim 1, characterized in that, The obtained DCPVC material exhibits photocatalytic activity in generating H2O2 from water and air under natural sunlight, and can also effectively photosynthesize H2O2 in seawater or aqueous solutions with certain acidity or alkalinity.

10. The application of the composite coating of DCPVC and polyelectrolyte prepared by the method for preparing antibacterial coating based on polyvinyl chloride plastic according to any one of claims 1-9 in antibacterial materials.

Images