Quarternary Phosphonium Modified Epoxidized Natural Rubber

In this thesis, a new chemically modified antimicrobial rubber was prepared.“Two steps method” was introduced to modify epoxidized natural rubber (ENR) usinghalogenated acid (HA) as bridge coupling agent. Quaternary phosphonium salts (QPS)were covalently bonded onto rubber chains by firstly ring-opening and thenquaternary phosphonium (QP) modification of ENR. The conditions and systems ofreaction were selected;“One step method” was tried and discussed, then the “twosteps method” was designed in this experiment. The ring-opening and QP reactions in“two steps method” was confirmed by FT-IR&1H-NMR analyses, and the degrees ofboth reactions were increased as they continue. Meanwhile, the potential reactionmechanisms and side reactions were investigated along with the researching ofmodified rubbers’ structures. DSC&TGA were used to study the thermal propertiesof unmodified and modified ENR. We found that both reactions made rise of glasstransition temperature (Tg) and fall of thermal stability. The structural factors whichcaused the changes of thermal properties were also researched. Antimicrobial activitywas analyzed using the ‘‘shaking flask method’’. The growth and proliferation of E.coli&S. aureus could be inhibited on QP modified ENR, and good bacterialinhibition rate was found with E. coli, which reached82.96%. The method presentedin this research hopefully provides new approaches to confer permanent antimicrobialproperties to natural rubber and other rubber products.