Towards Tailored Interphase Formation Utilizing Surface-Bound BenzylsulfoniumSalts as Cationic Initiators

摘要

This study centers on designed composite interphases based on using polymersynthesis to chemically link initiating groups to fiber surfaces, promote radial growth of the interphase out from the surface, and finally initiate matrix cure. The approach is based on tailoring interphase formation before matrix cure, and should help to develop very strong interactions between the composite components. Novel benzylsulfonium salts have been synthesized which possess an alkyl ether tether tied to a reactive trialkoxysilane moiety capable of covalently bonding with glass surfaces. Recently it has been shown that benzylic sulfonium salts can be excellent latent initiators for epoxy resins, vinyl ethers, and spiro orthocarbonates or bicyclo orthoesters. Here we report the coupling of these sulfonium salts with high surface area silica gel as a model for glass fibers. High surface area silica was chosen due to the high loadings achievable, allowing for more facile characterization of the degree of functionalization. The surface-bound sulfonium salts will be used to initiate the cationic polymerization of various resins based on epoxy functionality. Characterization of the surface-bound sulfonium salts on silica, cure kinetics of unbound and surface-bound initiator with a commercial epoxy resin system and preliminary composite formation with glass fibers will be presented.