Mechanical and thermal properties of the hybrid composites of vinylester resin and methacryl‐substituted polysilsesquioxane

Abstract Vinylester resin (VER) composed of bisphenol‐A‐based epoxy methacrylate and styrene was cured finally at 120°C with methacryl‐substituted polysilsesquioxane (ME‐PSQ) prepared from 3‐(trimethoxysilyl)propyl methacrylate and tetramethylammonium hydroxide. The dynamic mechanical and thermal properties of the VER/ME‐PSQ 90/10–60/40 hybrid composites were investigated when compared with crosslinked‐VER (C‐VER) and VER/phenyl‐substituted polysilsesquioxane (Ph‐PSQ) 80/20 composite cured at the same condition. As a result, the VER/ME‐PSQ hybrid composites showed much higher storage modulus (E′) at rubbery state than C‐VER and the VER/Ph‐PSQ composite. The E′ of the hybrid composites increased with increasing ME‐PSQ content. Also, coefficient of thermal expansion of the hybrid composites decreased with increasing ME‐PSQ content. The glass transition temperatures and 5% weight loss temperatures of the VER/ME‐PSQ hybrid composites were almost the same as those of C‐VER and the VER/Ph‐PSQ composite. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers