Preparation And Application Of Alkaline Polymer Nano - Micron Antibacterial Materials

Propagation of harmful microorganisms brings malign influence on human beings, such as food spoilage, wound infection, and water pollution, etc. It has been a major problem to be solved. Therefore, in recent years, various kinds of antibacterial materials, such as quaternary ammonium salt, metal ions, light-activated coating, quaternary phosphonium salts, and N-halamines have been reported. Among them, N-halamines have obtained wide attentions due to their powerful and broad spectrum bactericidal properties. At present, N-halamines have been applied in antibacterial coatings, antibacterial fabrics, disinfection of drinking water, and the degradation of hazardous substances. In this paper, two different types of polymeric N-halamine nano/micro particles were synthesized and their properties and applications were further studied.(1) Study on synthesis and antibacterial properties of polymeric N-halamine/quaternary ammonium salt nano/micro particles containing core-shell structure of SiO2-polystyreneThe nano/micro particles with Si O2 as the core and polystyrene(PS) as the shell(Si O2@PS N/MPs) were synthesized by an emulsion polymerization. The morphology of the as-synthesized Si O2@PS N/MPs was characterized by field emission scanning electron microscopy(FE-SEM) to determine the mass ratio of styrene, Si O2, and initiator when the size of the as-synthesized Si O2@PS N/MPs is the smallest. Then, the optimized conditions for chloromethylation and grafting N-halamine precursors were achieved by measuring the content of chloromethyl groups and oxidized chlorine after chloromethylation and grafting N-halamine precursors. In order to ensure the good dispersion of nanoparticles in water, we introduce the tertiary amine groups to produce quaternary ammonium salt with positive charges in the surface of the nano/micro particles during grafting the N-halamine precursors. At last, the powerful N-halamine polymeric antimicrobial nano/micro particles with the core-shell structure of Si O2-PS(Si O2@PSC-QAS-DMC N/MPs) were achieved through chlorinating the N-halamine precursors in the surface of nano/micro particles in dilute sodium hypochlorite solution. The structure and performance of the as-synthesized nano/micro particles were characterized by FTIR, XPS, TGA, and BET. Antibacterial testing results show that when the concentrations of the as-synthesized Si O2@PSC-QAS-DMC N/MPs are 32.00 and 40.00 μg/m L, Escherichia coli(7.3×107 CFU/m L) and Staphylococcus aureus(2.7×107 CFU/m L) could be completely killed within 50 and 60 min, respectively. Storage stability and regenerability experiments indicated that the N-halamine functional groups in the as-synthesized Si O2@PSC-QAS-DMC N/MPs have good storage stability and reproducibility.(2) Study on synthesis and antibacterial properties of N-halamine crosslinked polymeric nano/micro particlesAcrylic acid(AA) and methylene-bis-acrylamide(MBAA) were copolymerized in solution to produce the crosslinked polymeric nano/micro particles(PAA/MBAA N/MPs). During the copolymerization, the size of the nano/micro particles was adjusted by controlling the concentrations of initiator and monomers, reaction temperature, and the molar ratio of MBAA and AA. Then, the crosslinked N-halamine polymeric antimicrobial nano/micro particles(PAA/MBAA-Cl N/MPs) were obtained via a chlorination of PAA/MBAA N/MPs in dilute sodium hypochlorite solution. The as-synthesized PAA/MBAA-Cl N/MPs were characterized by field emission scanning electron microscopy(FE-SEM), FTIR, XPS, and DSC. The antibacterial test showed that the as-synthesized PAA/MBAA-Cl N/MPs have good antimicrobial efficacies. When the concentrations of the as-synthesized PAA/MBAA-Cl N/MPs are 35.00 and 45.00 μg/m L, Escherichia coli(5.3×107 CFU/m L) and Staphylococcus aureus(8.9×106 CFU/m L) could be completely killed within 60 and 70 min, respectively. Also, it was found that the N-halamine functional groups in the as-synthesized PAA/MBAA-Cl N/MPs have good storage stability.(3) Application of N-halamine crosslinked polymeric nano/micro particles in polyurethane membrane materialsPAA/MBAA-Cl N/MPs were added to the polyurethane solution to make the antibacterial polyurethane membrane by a wet-casting membrane formation. FE-SEM showed that the as-synthesized PAA/MBAA-Cl N/MPs have good dispersibility in polyurethane membrane. Finally, the antibacterial efficacy of the as-synthesized PAA/MBAA-Cl N/MPs was tested. The inhibition zone test showed that the diameters of inhibition zones were 20.15, 23.67, and 28.44 mm against S.aureus and 19.35, 27.78, and 31.67 mm against E.coli, respectively, when the mass percentages of PAA/MBAA-Cl N/MPs in the polyurethane membrane were 0.0625%, 0.25%, and 1.00%, respectively. It means that the polyurethane membrane containing some PAA/MBAA-Cl N/MPs have good antimicrobial performance.