Study On Synthesis Of Polymers Containing Hydrantoin, Their Chlorination And Their Antibacterial Activities

Contamination of material surfaces especially polymer material surfaces by micro-organisms is of great concern in several areas such as medical devices, health care products, hospital and dental office equipment, food packaging and food storage, etc. Consequently, biocidal polymer materials have received much attention in recent years. Currently there are several sorts of antibacterial polymers such as polymers containing heavy metal cations, pyridinium and quaternary ammonium salt polymers, and N-halamine polymeric biocides, among which, N-halamine polymeric biocides have shown to be disinfectants which provide almost instant and total kill of a wide range of micro-organisms. However, the types of antibacterial N-halamine polymers are limited until now; the antibacterial mechanism and the structure-antibacterial activity relationship are still uncertain. Therefore, there is a need to continue the research for novel antibacterial N-halamine polymers as well as to put much effort to get a better understanding of the antibacterial mechanism. In this paper, two series of antibacterial copolymers were prepared. The antibacterial acitivities of the copolymers were measured and the influential factors on the antibacterial activity were studied. The copolymerization behavior and antibacterial mechanism were also discussed in this study.A vinyl-hydantoin monomer, 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH), was synthesized. It was homopolymerized in radical polymerization. The monomer and homopolymer were fully characterized by IR and 'H-NMR.The copolymers of VBDMH with butylmethacrylate and methylmethacrylate were prepared in radical copolymerization respectively. The copolymers were characterized by IR and ' H-NMR. The copolymerization behaviors were studied. The effects of monomer feeds on the composition of the final copolymers and reaction conversion were investigated. The copolymers were chlorinated and the chlorinated copolymers were fully characterized with IR and ' H-NMR. The thermal properties of the copolymers were studied by DSC and TG. The results show that the copolymers have satisfying thermal stabilities. The antibacterial activities of the halogenated copolymers against Escherichia coli (E.coli) were studied. The results showed that the copolymers after chlorination can provide powerful antibacterial activities. The possible antibacterial mechanism was discussed.The synthesized monomer, 3-(4'-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH) also was copolymerized with styrene to obtain linear PSt-co-VBDMH. The copolymers were fully characterized by IR and 'H-NMR. The copolymerization behaviors were studied. It was found that the component of VBDMH in the copolymer increased with the increase of initial molar ratio feeds of VBDMH.3-(4'-vinylbenzyl)-5,5-dimethylhydantoin (VBDMH) also was copolymerized with styrene anddivinylbenzene to obtain crosslinked PSt-co-VBDMH beads in suspension polymerization. The crosslinked PSt-co-VBDMH beads were chlorinated. The copolymers before and after chlorination were characterized completely by 'H-NMR and IR, and the morphologies of the beads were observed by micropolariscope. DSC and TG studies show that the beads have good thermal stabilities. The antibacterial activities of the chlorinated PSt-co-VBDMH beads against E.coli were tested. The results showed that the copolymers after chlorination can provide powerful antibacterial activities. It was found that the antibacterial activity was increased with the increase of the VBDMH feeds. The possible antibacterial mechanism was indicated as follows: The chlorinated copolymer beads partly hydrolize in aqueous suspension to generate hypochloric acid. Hypochloric acid diffuses through the cell walls of E.coli and breaks the balance of glucoproteinase metabolism and causes the death of the cell. On the other hand, when the bacteria of E.coli contact with the immobile chlorine of the copolymer, chlorine makes the membrane abrupt by changing the permeability of cell membrane, and the cells die as a result.