Quaternary ammonium salt polymer antibacterial material based on PVC waste and preparation method thereof

Abstract

The invention belongs to the field of polymer materials, relates to the direction of resource utilization of plastic wastes, and discloses a quaternary ammonium salt polymer antibacterial material based on PVC (polyvinyl chloride) wastes and a preparation method of the quaternary ammonium salt polymer antibacterial material. According to the invention, quaternary ammonium salt groups with antibacterial activity are used for replacing part of chlorine atoms on a PVC waste chain through a chemical modification method, so that the macromolecular antibacterial material containing the chlorine atoms and the quaternary ammonium salt groups at the same time is obtained; the film is prepared by adopting a solution tape casting method, and an antibacterial property test is carried out by adopting a film contact method; test results show that the polymer film material has 99.9% of antibacterial effect on sensitive escherichia coli, chloramphenicol-resistant escherichia coli and staphylococcus aureus. The reaction system disclosed by the invention is relatively low in required temperature and low in energy consumption, does not need an expensive catalyst, can endow the PVC waste with a lasting antibacterial function while realizing partial dechlorination of the PVC waste, and shows huge practical application potential.

Description

Technical Field

[0001] The invention belongs to the field of polymer materials and relates to the resource utilization of plastic waste. Background Art

[0002] In recent years, the plastic industry has developed rapidly around the world, resulting in a large amount of plastic waste. Most of these wastes are non-biodegradable and can remain in the natural environment for decades or even hundreds of years, posing a serious threat to the ecological environment. However, plastic waste is rich in hydrocarbon resources, so it is called "resources in the wrong place". Therefore, how to realize the resource utilization of plastic waste has become a key issue in controlling plastic pollution and protecting the environment. Among them, polyvinyl chloride (PVC), known as the "fighter among toxic plastics", is widely used in construction, wires and cables, transportation, food packaging, medical care, and leisure and entertainment due to its low cost, chemical corrosion resistance, acid and alkali resistance, and excellent mechanical properties. At present, the annual global production of PVC has exceeded 40 million tons, with my country's production ranking first. However, with the high production comes a large amount of difficult-to-handle PVC waste. Because PVC waste contains a large amount of chlorine atoms and environmentally unfriendly additives, its biodegradability is extremely poor, and it is easy to cause serious pollution to the ecological environment. Therefore, how to scientifically and rationally dispose of PVC waste has become one of the major environmental challenges that need to be solved today.

[0003] At present, there are four ways to deal with PVC waste in my country: landfill, incineration, mechanical recycling and chemical recycling. However, landfill requires a large amount of land, and this method usually releases harmful organic chlorides and corrosive hydrochloric acid (HCl), which may damage recycling equipment and poison catalysts. Incineration produces a large amount of corrosive hydrochloric acid, and may also release dioxins, the "poison of the century". In addition, the bottom ash after incineration contains a large amount of harmful substances, causing secondary pollution. Mechanical recycling has more advantages than landfill and incineration. It can reuse PVC waste and save resources. However, the mechanical stability of recycled plastics decreases step by step, and the scope of application is narrowed. In the end, it becomes waste that harms the environment and human health. Chemical recycling refers to the use of chemical treatment to convert PVC waste into chemical raw materials, fuels or high-value-added materials, including general thermal cracking, catalytic thermal cracking and wet methods. However, PVC waste contains a large amount of chlorine. The general thermal cracking method (hydrogenation, pyrolysis and gasification) will produce hydrochloric acid to corrode the recovery equipment and pipelines. At the same time, the chlorine-containing organic products obtained cannot be used as chemical raw materials or fuels, and may even produce harmful substances such as dioxins, polychlorinated biphenyls, and persistent organic pollutants. Therefore, dechlorination is a key issue that needs to be solved in order to realize the resource utilization of PVC waste. It is reported that chlorine-containing compounds (such as chloramphenicol) are widely used due to their significant antibacterial effects. Therefore, whether PVC can be converted into high-molecular antibacterial materials without complete dechlorination is worth further exploration.

[0004] With the frequent outbreaks of cold chain-related epidemics, the surface transmission of microorganisms has attracted widespread attention. Quaternary ammonium antimicrobial agents are widely used. Quaternary ammonium salts are compounds generated by replacing four hydrogen atoms in ammonium ions with alkyl groups. They are cationic surfactants with strong antibacterial ability, a wide antibacterial spectrum and easy access. Quaternary ammonium antimicrobial agents are widely used in industries such as medical, household, water treatment and food. According to the latest data from the US Environmental Protection Agency, quaternary ammonium salts account for 342 of the more than 600 antimicrobial disinfectants, showing their importance in the field of antimicrobial disinfection. However, common quaternary ammonium antimicrobial agents usually have a relative molecular weight of less than 500 (such as benzalkonium chloride), exist in the form of solutions, are easy to elute and volatilize, have poor antibacterial persistence, are difficult to reuse, and have low efficiency. Patent CN201410348600.7 discloses a PVC / PVC-g-DMC antibacterial plastic and its preparation technology, which grafts PVC with quaternary ammonium salt groups. Since the quaternary ammonium salt group itself has bactericidal properties, PVC-g-DMC itself is a polymer antibacterial agent. According to the plastic antibacterial performance test QB / T 2591-2003, its bactericidal rate against Escherichia coli and Staphylococcus aureus exceeds 98%. However, grafting has harsh reaction conditions and may produce side reactions; quaternary ammonium salt groups are usually expensive and the cost increases accordingly; the recycling of resources is not achieved, and the waste generated affects the environment. In contrast, the use of PVC waste to prepare polymer antibacterial surfaces has great application potential in preventing bacterial surface transmission, can achieve resource recycling, and reduce adverse effects on the environment. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a quaternary ammonium salt polymer antibacterial material based on PVC waste and a preparation method thereof.

[0006] The technical solution of the present invention is achieved in this way: On the one hand, the present invention provides a quaternary ammonium salt polymer antibacterial material based on PVC waste, and its structural formula is shown in Formula I: Formula I In the formula, m and n are natural numbers greater than 2000, and m:n=(0.9-1):1. The average molecular weight of the structural formula is 200000 Da-220000 Da.

[0007] In the second aspect, the present invention provides a novel quaternary ammonium salt polymer antibacterial material (PQAM), which is prepared by modifying the quaternary ammonium salt group on the long chain structure of PVC waste so that it has two antibacterial groups, quaternary ammonium salt group and chlorine atom. The preparation method is as follows: a. Partial dechlorination of PVC waste: 4-aminothiophenol is used to replace some chlorine atoms in PVC waste by the bridging method to obtain an intermediate product; b. Methylation of amino group: -NH 2 Reaction with iodomethane gives the target product (Formula I).

[0008] In the preparation method of the quaternary ammonium salt polymer antibacterial material provided by the present invention, PVC waste and 4-aminothiophenol are reacted by bimolecular nucleophilic substitution reaction to obtain an intermediate product; then, methyl iodide is used to methylate the -NH 2 , and the target product (PQAM) is obtained.

[0009] In the above preparation method, any amount of raw materials that can promote the above bimolecular nucleophilic substitution reaction is feasible. In order to improve the reaction yield and raw material utilization rate, preferably, the mass ratio of PVC waste to 4-aminothiophenol in step a is 1:(0.4-1), and the mass ratio of the intermediate product to methyl iodide in step b is 1:(5-8).

[0010] The specific preparation steps are as follows: (1) PVC waste and 4-aminobenzenethiophenol undergo bimolecular nucleophilic substitution reaction to obtain an intermediate product; (2) Methyl iodide and the intermediate product of step (1) undergo a bimolecular nucleophilic substitution reaction to obtain a quaternary ammonium salt-based polymer antibacterial material.

[0011] Preferably, the solvent for the bimolecular nucleophilic substitution reaction in the above steps (1) and (2) is N,N-dimethylformamide or N,N-dimethylacetamide.

[0012] Preferably, a weak base is added to the bimolecular nucleophilic substitution reaction of step (1) and step (2), and the weak base is K 2 CO 3 Or Na 2 CO 3 .

[0013] Preferably, in the above step (1), the molar ratio of PVC waste to 4-aminothiophenol is 1:(0.4-1), and the mass ratio of the intermediate product to methyl iodide in step (2) is 1:(5-8).

[0014] Preferably, the temperature of the bimolecular nucleophilic substitution reaction in the above step (1) is 70-90°C, and the reaction time is 5-7h. The temperature of the bimolecular nucleophilic substitution reaction in step (2) is room temperature-35°C, and the reaction time is 12-14h.

[0015] In a third aspect, a quaternary ammonium salt polymer material film / coating is obtained by dissolving the above-mentioned quaternary ammonium salt polymer antibacterial material and then coating it.

[0016] Fourthly, the above-mentioned quaternary ammonium salt polymer film / coating is used as an antibacterial material.

[0017] Preferably, the above-mentioned antibacterial agent refers to anti-Escherichia coli or Staphylococcus aureus.

[0018] The present invention has the following beneficial effects: (1) The present invention proposes a novel quaternary ammonium salt polymer antibacterial material based on PVC waste and a preparation method thereof. A quaternary ammonium salt group with antibacterial activity is used to replace part of the chlorine atoms on the PVC chain by a chemical modification method, thereby obtaining a polymer antibacterial material PQAM containing both chlorine atoms and quaternary ammonium salt groups. A film is prepared by a solution casting method, and the antibacterial performance is tested by a film contact method, which shows that the antibacterial effect of the PQAM film is negatively correlated with the initial concentration of Gram-negative bacteria and positively correlated with the contact time. The antibacterial activity is mainly achieved through the synergistic bactericidal mechanism between the quaternary ammonium salt group containing cations and the long carbon chain with hydrophobic properties. The antibacterial mechanism of the PVC film does not only rely on its hydrophobicity, but chlorine atoms also play an important role in killing Gram-positive bacteria.

[0019] (2) The novel polymer antibacterial material PQAM prepared by the present invention has an antibacterial effect of 99.9% against sensitive Escherichia coli, chloramphenicol-resistant Escherichia coli and Staphylococcus aureus. It is applied on the surface of glass jars, stainless steel door handles and wooden boards. E. coli BL21 and S. aureus All of them have good antibacterial activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 To functionally upgrade PVC waste to high value-added quaternary ammonium polymer antibacterial materials (PQAM).

[0022] Figure 2 This is the preparation route of PQAM.

[0023] Figure 3 This is the infrared spectrum (FT-IR) of PQAM.

[0024] Figure 4 is the hydrogen spectrum of PQAM ( 1 H NMR).

[0025] Figure 5 The differential calorimetry and thermogravimetric analysis curves of PQAM.

[0026] Figure 6 The antimicrobial durability and reusability of PQAM.

[0027] Figure 7 Schematic diagram of film preparation and antibacterial performance testing.

[0028] Figure 8 For PQAM film E. coli Antimicrobial activity test of BL21.

[0029] Fig. 9 For PQAM film E. coli Antimicrobial activity test of C.

[0030] Fig.10 For PQAM film S. aureus Antimicrobial activity test.

[0031] Fig.11 Antimicrobial effect of PQAM coating on glass jars.

[0032] Fig.12 PQAM coating on stainless steel door handles E. coli BL21 and S. aureus Antibacterial effect.

[0033] Fig.13 PQAM coating on wood board E. coli BL21 and S. aureus Antibacterial effect. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the experimental methods used in the following experimental examples are all conventional methods; the materials and reagents used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0036] This application develops an innovative upcycling strategy ( Figure 1), that is, by chemical modification, the quaternary ammonium salt group is grafted onto the PVC chain in the form of a covalent bond, and converted into a new type of quaternary ammonium salt polymer antibacterial material PQAM. This material not only maintains the antibacterial activity of the original chlorine atoms of PVC, but also increases the antibacterial properties of the quaternary ammonium salt group.

[0037] The invention discloses a method for preparing a quaternary ammonium salt polymer antibacterial material PQAM. PVC and 4-aminothiophenol are reacted by a bimolecular nucleophilic substitution reaction to obtain an intermediate product. Then, methyl iodide is used to methylate the -NH 2 , and the target product (PQAM) is obtained. 2 CO 3 Or Na 2 CO 3 It is used to neutralize the HCl produced in the reaction system. The preparation method has mild reaction conditions, is easy to control, uses readily available raw materials, does not require the addition of oxidants, strong acids or strong bases during the reaction, and has strong reaction specificity. The substitution rate of chlorine atoms on PVC and the elimination rate of HCl are controllable, and the post-processing is convenient, green and environmentally friendly, and suitable for large-scale industrial production.

[0038] Example 1 This embodiment uses a chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM) in two steps, such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel, and a condenser. Add PVC waste (6 g, Mw value about 130000 Da), 4-aminothiophenol (2.4 g), K 2 CO 3 (1.33 g) and DMF (120 mL). Under nitrogen protection, the system was heated to 70 ° C. The reaction was stopped after 6 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid crude product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product). The intermediate product was transferred to a vacuum drying oven (China Jinghong, XMTD-8222) and continued to dry for 48 h.

[0039] (II) In the second step, the intermediate product (1.5 g), iodomethane (6 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 35 °C and maintained for 12 h. After the reaction was completed, K 2 CO 3, 1.5 g of iodomethane was added to the reaction solution and stirred at room temperature for 2 h. After the reaction was completed, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, 210000 Da). Finally, PQAM was placed in a vacuum drying oven for 48 h. The intermediate product and PQAM were characterized using infrared spectrometer (FT-IR, NicoletiS50, Thermo Fisher, USA), nuclear magnetic resonance (NMR, Bruker, Germany, Ascend 500), differential scanning calorimeter (DSC, TA, USA, Q2000) and thermogravimetric analyzer (TGA, TA, USA, SDT-Q600).

[0040] Compared with PVC, the FT-IR spectrum of the intermediate product ( Figure 3 ) showed two new absorption peaks at 3483 and 3383 cm -1 Belongs to -NH 2 The stretching vibration absorption peaks are 1671, 1619 and 1596 cm -1 The absorption peak of the skeleton vibration of the benzene ring. These results show that 4-aminothiophenol successfully replaced some chlorine atoms in PVC, that is, a bimolecular nucleophilic substitution reaction occurred. In the FT-IR spectrum of PQAM, -NH 2 The absorption peak of PVC disappeared, and the absorption peak of the skeleton vibration of the benzene ring also changed significantly compared with the intermediate product. 1 H NMR spectrum ( Figure 4 ) at 2.23-2.57 ppm is H a The absorption peak of H b The absorption peak of PQAM 1 In the H NMR spectrum, H g The absorption peak of the intermediate product -NH 2 The absorption peak disappears, which is because -NH 2 Methylation occurs, and H f The absorption peak of H e The absorption peak shifted from 7.08 to 7.23 ppm downfield, indicating the formation of quaternary ammonium groups in PQAM. In addition, the crystallinity of PQAM was evaluated using DSC. The crystallinity of the material did not change significantly from PVC to PQAM, and the glass transition temperatures of PVC and PQAM were 80.1°C and 79.1°C, respectively. Then, the thermal stability of PQAM was evaluated by TGA ( Figure 5), the degradation process of PQAM and PVC both showed two stages. In particular, the temperature required for PQAM to lose 5 wt.% weight was 175.1℃, while the temperature required for PVC was 274.6℃, which indicated that the thermal stability of PQAM was lower than that of PVC.

[0041] The polymer material PQAM usually exists in solid form, has the characteristics of stable chemical properties, not easy to elute and not easy to volatilize, has a long-lasting antibacterial effect and can be reused ( Figure 6 ), thereby significantly reducing the impact on the environment. The antibacterial material is suitable for product surfaces and can effectively inhibit the growth and reproduction of microorganisms on the surface of objects, improve hygiene levels, reduce the risk of disease transmission, reduce cleaning frequency, and improve safety. Its structure is shown in Formula I: Formula I Example 2 This embodiment adopts a two-step chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM), such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel and a condenser, and add PVC waste (6 g, Mw value about 130000 Da), 4-aminothiophenol (6 g), K 2 CO 3 (1.33 g) and N, N-dimethylformamide (DMF, 120 mL). Under nitrogen protection, the system was heated to 70 ° C. The reaction was stopped after 6 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid crude product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product). The intermediate product was transferred to a vacuum drying oven and continued to dry for 48 h.

[0042] (II) In the second step, the intermediate product (1.5 g), iodomethane (10.5 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 35 °C and maintained for 12 h. After the reaction was completed, K 2 CO 3 , 1.5 g of iodomethane was added to the reaction solution and stirred at room temperature for 2 h. After the reaction was completed, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, about 220,000 Da), and finally PQAM was placed in a vacuum drying oven for 48 h.

[0043] Example 3 This embodiment adopts a two-step chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM), such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel and a condenser. Add PVC waste (6 g, Mw value about 130000 Da), 4-aminobenzenethiol (3.6 g), K 2 CO 3 (1.33 g) and N, N-dimethylformamide (DMF, 120 mL). Under nitrogen protection, the system was heated to 80 ° C. The reaction was stopped after 5 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid crude product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product). The intermediate product was transferred to a vacuum drying oven and continued to dry for 48 h.

[0044] (II) In the second step, the intermediate product (1.5 g), iodomethane (7.5 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 35 °C and maintained for 14 h. After the reaction was completed, K 2 CO 3 , 1.5 g of iodomethane was added to the reaction solution and stirred at room temperature for 2 h. After the reaction was completed, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, about 200,000 Da), and finally PQAM was placed in a vacuum drying oven for 48 h.

[0045] Example 4 The present embodiment adopts chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM) in two steps, such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel and a condenser. Add PVC waste (6 g, Mw value about 130000 Da), 4-aminothiophenol (4.2 g), K 2 CO 3(1.33 g) and DMF (120 mL). Under nitrogen protection, the system was heated to 80 ° C. The reaction was stopped after 5 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid crude product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product), which was transferred to a vacuum drying oven and continued to dry for 48 h.

[0046] (II) In the second step, the intermediate product (1.5 g), iodomethane (10.5 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 35 °C and maintained for 14 h. After the reaction was completed, K 2 CO 3 , 1.5 g of iodomethane was added to the reaction solution and reacted at room temperature for 2 h. After the reaction, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, about 2100000 Da), and finally PQAM was placed in a vacuum drying oven for 48 h.

[0047] Example 5 This embodiment adopts a two-step chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM), such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel and a condenser, and add PVC waste (6 g, Mw value about 130000 Da), 4-aminothiophenol (4.8 g), K 2 CO 3 (1.33 g) and N, N-dimethylformamide (DMF, 120 mL). Under nitrogen protection, the system was heated to 90 ° C. The reaction was stopped after 7 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid crude product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product). The intermediate product was transferred to a vacuum drying oven and continued to dry for 48 h.

[0048] (II) In the second step, the intermediate product (1.5 g), iodomethane (10.5 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 25 °C and maintained for 14 h. After the reaction was completed, K 2 CO 3, 1.5 g of iodomethane was added to the reaction solution and stirred at room temperature for 2 h. After the reaction was completed, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, about 220,000 Da), and finally PQAM was placed in a vacuum drying oven for 48 h.

[0049] Example 6 The present embodiment adopts chemical modification method to synthesize quaternary ammonium salt polymer antibacterial material (PQAM) in two steps, such as Figure 2 As shown, the specific steps are as follows: (I) Prepare a three-necked flask equipped with a magnetic stirrer, an addition funnel and a condenser, and add PVC waste (6 g, Mw value about 130000 Da), 4-aminothiophenol (6 g), K 2 CO 3 (1.33 g) and N, N-dimethylformamide (DMF, 120 mL). Under nitrogen protection, the system was heated to 90 ° C. The reaction was stopped after 7 h. After cooling to room temperature, the reaction solution was slowly poured into 200 mL of deionized water and filtered to obtain a solid product. Subsequently, it was dissolved in an appropriate amount of tetrahydrofuran (THF) for purification, and recrystallized from deionized water to obtain a solid product (intermediate product). The intermediate product was transferred to a vacuum drying oven and continued to dry for 48 h.

[0050] (II) In the second step, the intermediate product (1.5 g), iodomethane (10.5 g) and K 2 CO 3 (3.13 g) was added to DMF (30 mL), and the reaction solution was heated to 25 °C and maintained for 14 h. After the reaction was completed, K 2 CO 3 , 1.5 g of iodomethane was added to the reaction solution and stirred at room temperature for 2 h. After the reaction was completed, the reaction solution was poured into 90 mL of deionized water, stirred evenly, and then freeze-dried to obtain a solid product (i.e., PQAM, about 220,000 Da), and finally PQAM was placed in a vacuum drying oven for 48 h.

[0051] Implementation effect example The antibacterial film was prepared using the quaternary ammonium salt polymer material of Example 1 and the antibacterial performance was tested. Figure 7 As shown, the specific steps are as follows: First, PVC waste (20 mg) and quaternary ammonium salt polymer antibacterial material (20 mg) were dissolved in THF (2 mL) respectively. After stirring for 30 min, they were slowly poured into a sterilized glass petri dish, left to stand in a clean fume hood for 2 h, and then transferred to a vacuum drying oven and continued to dry for 48 h. Subsequently, scanning electron microscopy (Hitachi, Japan, S-4800) analysis results showed that the surfaces of all films showed rough and uneven characteristics, which helped to enhance the adhesion of the film to bacteria.

[0052] The antibacterial performance of the antibacterial film was tested by the film contact method. The results showed that it had an antibacterial effect of 99.9% against sensitive Escherichia coli, chloramphenicol-resistant Escherichia coli and Staphylococcus aureus. The antibacterial mechanism was studied as follows: 1. The film material of PQAM provided by the present invention prepared by solution casting method is sensitive to Escherichia coli ( E. coli BL21), chloramphenicol-resistant Escherichia coli ( E. coli C) and Staphylococcus aureus ( S. aureus ) has an antibacterial effect of 99.9%. Figure 8 (a) It can be observed that E. coli BL21 cells can grow normally in PBS. However, after adding PQAM film to the bacterial solution, the number of bacteria decreases with the increase of contact time and finally drops to zero ( Figure 8 (c)), which shows that the PQAM film E. coli BL21 has obvious antibacterial activity. The antibacterial rate results of PVC film show that its antibacterial effect is similar to E. coli The initial concentration of BL21 was negatively correlated ( Figure 8 (d)). This means that the antibacterial effect of PQAM film decreases with the increase of initial bacterial concentration.

[0053] 2. The present invention also detects the effect of PQAM film on E. coli The experimental results show that with the increase of contact time, E. coli The concentration of C decreases continuously to zero ( Fig. 9 (c)). At the same time, the antibacterial rate of PQAM film also increases with E. coli The initial concentration of C decreases and increases ( Fig. 9 (d)), this trend is consistent with E. coli The inhibition rate of BL21 was consistent ( Figure 8 (d)). This result shows that: E. coliThe hydrophobicity of the material plays an important role in the reproduction process, while the chlorine atoms on PVC do not significantly affect the antibacterial effect. We speculate that the antibacterial activity of PQAM film against Gram-negative bacteria is mainly achieved through the synergistic bactericidal mechanism between the quaternary ammonium salt groups containing cations and the long carbon chains with hydrophobic properties.

[0054] 3. The present invention also tests the effect of PQAM film on S. aureus Antibacterial activity. Fig.10 As can be seen in (a), S. aureus The concentration of the suspension in PBS decreases with time. When the PQAM film is added, the number of bacteria continues to decrease with the increase of contact time and finally drops to zero ( Fig.10 (c)), which indicates that this type of film S. aureus It has obvious antibacterial activity. Fig.10 (d) shows that the antibacterial activity of PQAM film is positively correlated with the contact time. S. aureus The initial concentration of E. coli However, E. coli Compared with the antibacterial effect at 24 h, S. aureus The initial concentration is 10 3 CFU / mL, its inactivation time was significantly shortened to about 12 h. Interestingly, when the PVC film was exposed to S. aureus When the suspension was used, the bacterial concentration also continued to decrease with the increase of contact time ( Fig.10 (b)), which explains the effect of PQAM film on S. aureus The antibacterial efficiency is higher than E. coli In addition, this also means that PVC kills S. aureus The mechanism of chlorine killing does not rely solely on its hydrophobicity. Based on the disinfection effect of chlorine atoms, it is speculated that chlorine atoms may play an important role in killing Gram-positive bacteria.

[0055] Application Example 1 The present invention coats PQAM on the surface of a glass jar to produce a PQAM antibacterial surface. The plate colony counting method is used to determine the effect of the PQAM coating on E. coli BL21 and S. aureus The PQAM coating applied on the glass jar had a sterilization rate of E. coli BL21 and S. aureus The antibacterial activity of PQAM coating increased with the contact time, which is consistent with the E. coli BL21 and S. aureus The performance in suspension is consistent, and the PQAM coating has S. aureus The antibacterial activity was higher than E. coli BL21. In addition, E. coli BL21 concentration ranged from 3×10 3 It takes 12 h for CFU / mL to drop to zero ( Fig.11 (a)), while S. aureus The concentration ranged from 8×10 3 It only takes 6 hours for CFU / mL to drop to zero ( Fig.11 (b)). The above results show that PQAM coating has S. aureus Compare E. coli BL21 was more effective, probably due to the disinfecting properties of chlorine atoms. E. coli BL21 and S. aureus It has good antibacterial activity, indicating that it has potential for practical application.

[0056] Application Example 2 The present invention applies PQAM on a stainless steel door handle to produce a PQAM antibacterial surface. The plate colony counting method is used to determine the effect of the PQAM coating on E. coli BL21 and S. aureus The PQAM coating applied on the door handle has a sterilization rate of E. coli BL21 and S. aureus All showed 99.9% antibacterial activity ( Fig.12 ). As the contact time increases, the antibacterial rate of the PQAM coating increases, and the PQAM coating S. aureus The antibacterial activity was higher than E. coli BL21, which is a PQAM coating on glass jars E. coli BL21 and S. aureus The antibacterial effect is consistent. Therefore, the PQAM coating attached to the steel door handle has E. coli BL21 and S. aureus Has good antibacterial activity.

[0057] Application Example 3 The present invention coats PQAM on a wooden board to produce a PQAM antibacterial surface. The plate colony counting method is used to determine the effect of the PQAM coating on the E. coli BL21 and S. aureus The bactericidal rate of PQAM coating on the wood board was 1. E. coli BL21 and S. aureus All showed 99.9% antibacterial activity ( Fig.13 ). As the contact time increases, the antibacterial rate of the PQAM coating increases, and the PQAM coating S. aureus The antibacterial activity was higher than E. coliBL21, which is in contrast to the PQAM coating on glass jars and stainless steel door handles E. coli BL21 and S. aureus The antibacterial effect is consistent. Therefore, the PQAM coating attached to the wood board has E. coli BL21 and S. aureus Has good antibacterial activity.

[0058] In summary, the present invention develops a novel functional upgrading strategy that can controllably transform PVC waste into valuable quaternary ammonium salt-based polymer antimicrobial materials, aiming to reduce the surface transmission of pathogens, and shows great application potential in the fields of cold chain packaging, public health, transportation, and construction.

Claims

1. A quaternary ammonium salt polymer antibacterial material based on PVC waste, the structural formula of which is shown in Formula I: Formula I In the formula, m and n are natural numbers greater than 2000, and m:n=(0.9-1):

1. The average molecular weight of the structural formula is 200000 Da-220000 Da.

2. The method for preparing the quaternary ammonium salt polymer antibacterial material according to claim 1, characterized in that: The preparation steps are as follows: (1) PVC waste and 4-aminobenzenethiophenol undergo bimolecular nucleophilic substitution reaction to obtain an intermediate product; (2) Methyl iodide and the intermediate product of step (1) undergo a bimolecular nucleophilic substitution reaction to obtain a quaternary ammonium salt-based polymer antibacterial material.

3. The method for preparing a quaternary ammonium salt macromolecular antibacterial material according to claim 2, wherein: The solvent for the bimolecular nucleophilic substitution reaction in step (1) and step (2) is N,N-dimethylformamide or N,N-dimethylacetamide.

4. The method for preparing a quaternary ammonium salt macromolecular antibacterial material according to claim 3, wherein: A weak base is also added in the bimolecular nucleophilic substitution reaction of step (1) and step (2), and the weak base is K2CO3 or Na2CO3.

5. The method for preparing the quaternary ammonium salt polymer antibacterial material according to claim 4, characterized in that: In the step (1), the mass ratio of PVC waste to 4-aminothiophenol is 1:(0.4-1).

6. The method for preparing the quaternary ammonium salt polymer antibacterial material according to claim 2, characterized in that: The mass ratio of the intermediate product to methyl iodide in step (2) is 1:(5-8).

7. The method for preparing a quaternary ammonium salt polymer antibacterial material according to any one of claims 2 to 6, characterized in that: The temperature of the bimolecular nucleophilic substitution reaction in step (1) is 70-90°C, and the reaction time is 5-7 h. The temperature of the bimolecular nucleophilic substitution reaction in step (2) is room temperature-35°C, and the reaction time is 12-14 h.

8. A quaternary ammonium salt polymer material film / coating, characterized in that: The method is obtained by dissolving the quaternary ammonium salt polymer antibacterial material according to claim 1 and then coating the dissolution material.

9. Use of the quaternary ammonium salt polymer material film / coating according to claim 8 as an antibacterial material.

10. The use according to claim 9, characterized in that: The antibacterial agent refers to anti-Escherichia coli or Staphylococcus aureus.

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