Study On Properties Of Antibacterial LDPE By Reactive Extrusion

Bacteria and other pathogenic microorganisms is one kind of major killers of human health. The bacteria are bred from the surface contamination of plastic product and a threat to the health of people who utilize or tough them. Antimicrobial material becomes a hot topic in the modern society, especially the materials of packing need a break on antimicrobial, which could be reduce infection that caused by bacteria. Antimicrobial packing shows its bactericidal effect through the usage of packaging materials to inhibit the growth of microorganisms and avoid secondary infection during storage products, thus extending the shelf life.The antibacterial agent is the core of antimicrobial packing materials study. The preparation of the antibacterial LDPE which has good antibacterial effect as a goal, the Tributyl-3-[(and4-)vinyl benzyl]phosphonium Chloride was synthesized with3-(and4-)chlorome thylstyrene and Tributylphosphine. Then its chemical structure was illustrated by IR and NMR spectrum. And heat stability of the compounds was studied too. The antibacterial activity of the tributyl phosphonium salt against E.coli and S.aureus were investigated by inhibitory zone antibacterial experiments and MIC method. The inhibitory zone antibacterial experiments showed that there was good antibacterial activity of the tributyl phosphonium salt against E.coli and S.aureus. The result of MIC test indicated that, the minimal inhibitory concentrations of the tributyl phosphonium salt against E.coli and S.aureus were0.4g/L and0.3g/L, respectivily. Some factors such as contact time, concentration and pH which affect the antibacterial activity of the antibacterial agentwere studied detailly.The antibacterial LDPE was prepared through the reactive extrusion with the tributyl-3-[(and4-) vinyl benzyl] phosphonium.The effects of the extrusion temperature and the amount of initiator and agent were investigated on the grafted product. The chemical titration was used to deduce the grated rate of the tributyl-3-[(and4-) vinyl benzyl] phosphonium on LDPE. The sterilization effect of the grafted product against E.coli and S.aureus were studied by the method of pad pasting. At the same time the tensile strength, bending strength and impact strength were tested. When the quarter phosphonium salt content reached2%, the antibacterial rate were96%for E. coli, and above99%for S. aureus. It’s with strong antibacterial effect when the quarter phosphonium salt (QP) content reached3%or4%, and the antibacterial rate were more than99%for the S. aureus and E. coli.The optimum reaction process was determined through the above results to prepare antibacterial LDPE at high graft rate and with excellent antibacterial properties. Based on above results the antibacterial LDPE film was prepared with the tributyl-3-[(and4-) vinyl benzyl] phosphonium as antibacterial. By adjusting the parameters in the blown film process the antibacterial LDPE film was prepared using the method of blowing up film. The sterilization effect of the the antibacterial LDPE film against E.coli and S.aureus studied. Then the mechanical properties of the tensile strength, elongation at break, hot sealing strength, impact strength, friction coefficient etc. of the antibacterial LDPE film were tested, meanwhile, its health performance was also checked. It can be determined that the prepared antibacterial LDPE film had reached the standard requirement of antimicrobial packaging film through above studied characters.