Study On Synthesis Of Polymeric Methacrylic Acid Ester Antibacterial Agents With Quaternary Phosphonium Salt Groups And Its Application In Antibacterial ABS Plastics

ABS plastic has been widely used in domestic appliances such as refrigerators,air conditioners,washing machines and computers,due to its excellent comprehensive properties.However,these appliances will be contaminated by bacteria during usage.Because some bacteria are pathogenic,people might be infected and get sick when they touch these products.Therefore,developing antibacterial ABS plastic is not only meaningful in scientific research,but also valuable in application.According to the available researches,incorporating inorganic antibacterial agents is the main method to endow ABS plastic with antibacterial properties.The report of incorporating organic antibacterial agents or macromolecule antibacterial agents is rare because of their poor thermal stability,which might lead to the thermal decomposition of organic agentsduring ABS processing.However,the leaching effect of the inorganic antibacterial agents may lead to the short-term effect as well as the unsafety problem of the antibacterial ABS plastic.As unleachable agents,macromolecule antibacterial agents can solve problems of inorganic antibacterial agents,but their thermal stability needs to be improved.In this study,two kinds of polymeric methacrylic acid ester with quaternary phosphonium salt group were synthesized and incorporated into ABS plastic through double screw extruder to prepare antibacterial ABS plastic.And all results were listed as below:?1?Four kinds of methacryloyloxyalkyltriphenyl-phosphonium bromide?BrMAP-n?antibacterial monomers were synthesized via the reactions between methacryloyl chloride,alkyl bromide?3-bromopropan-1-ol,6-bromo-1-hexanol,9-bromo-1-nonanol,and11-bromo-1-undecanol?and triphenylphosphine.The structures of BrMAP-n were confirmed by ¹H-NMR and FT-IR spectra.All of BrMAP-n exhibited stronger antibacterial effects against S.aureus than E.coil,and their antibacterial properties increased with the increasing of alkyl chain length;?2?The BrMAP-n antibacterial monomers were homopolymerized and copolymerized with styrene by UV irradiation?254 nm?using 2,2-Dimethoxy-2-phenylacetophenone as photoinitiator,and two kinds of polymers named PBrMAP-n and PBSt-m were obtained,respectively.All of the polymers were confirmed by ¹H-NMR and FT-IR spectra.The 5%weight loss temperature(T_5%)in thermo-gravimetric analysis of the polymers ranged from202°C to 269°C,so they could be used as antibacterial agents in the ABS processing;?3?The T_5%and the glass-transition temperature?T_g?of PBrMAP-n/ABS-x antibacterial plastics were lower than those of neat ABS plastics,which decreased with the increasing of additive amount and side alkyl chain length.Incorporation of PBrMAP-n had no significant influence on the tensile strength,flexural strength and flexural modulus of ABS plastic,but dramatically reduced the impact strength.The impact strength decreased with the increasing of PBrMAP-n amount.When the side alkyl chain length of PBrMAP-n increased,the impact strength increased at first and then decreased.Incorporation of modified carbon nanotubes?MWCNTs?successfully enhanced the mechanical properties of PBrMAP-11/ABS-10antibacterial plastic without making an effect on the antibacterial properties.When the additive amount was 0.5 wt%,the PBrMAP-11/ABS-10/CNTs antibacterial composite showed the best impact strength;?4?Incorporation of PBrMAP-n could endow ABS plastic with antibacterial properties.The antibacterial properties of PBrMAP-n/ABS-x antibacterial plastics increased with the increasing of additive amount and the side alkyl chain length of PBrMAP-n.Among them,PBrMAP-11/ABS-10 antibacterial plastic showed an antibacterial rate over 99.99%against E.coil and 100%against S.aureus.All of the PBrMAP-n/ABS-x antibacterial plastics showed non-leaching effect,and their antibacterial properties became better after being immersed in deionized water for 15 days and 30 days,showing long term effect;?5?Compared with PBrMAP-11/ABS-10 antibacterial plastic,PBSt-m/ABS antibacterial plastics showed higher T_5%,T_g and better mechanical properties.The T_5%and mechanical properties increased with the increasing of styrene content in PBSt-m.The impact strength of PBSt-50/ABS antibacterial plastic were significantly higher than the PBrMAP-11/ABS-10antibacterial plastic;?6?All of the PBSt-m/ABS antibacterial plastics showed non-leaching effect.Their antibacterial activities were lower than PBrMAP-11/ABS-10 antibacterial plastic,but the antibacterial rate against E.coil and S.aureus were still over 90%.PBSt-m/ABS antibacterial plastics showed non-leaching effect.After being immersed in deionized water for 15 days and30 days,the antibacterial properties of the PBSt-m/ABS antibacterial plastics reduced at first and then raised.After immersion for 30 days,PBSt-m/ABS still showed an antibacterial rate over 90%against E.coil and S.aureus,showing long term effect;?7?Incorporation of PBrMAP-11 could also endow PP plastic and PA6 plastic with outstanding antibacterial properties.The tensile strength,flexural strength,flexural modulus and impact strength of PBrMAP-11/PP-10 antibacterial plastic were lower than pure PP plastic but the decline rates were small.Therefore,the PBrMAP-n also have potential to be used as antibacterial agents in other plastics.