Nonisothermal Curing Kinetics and Physical Properties of Unsaturated Polyester Modified with EA-POSS

Abstract

The polyhedral oligomeric silsesquioxanes (EA-POSS) which contain epoxy acrylate group were synthesized from 3-glycidypropyl-trimethoxysilane (GTMS) and acrylic acid in two steps: hydrolytic condensation of GTMS and esterification of polyhedral oligomeric silsesquioxanes epoxy resin (POSSER) with acrylic acid under appropriate conditions. The unsaturated polyester resin (UPR) was mixed with EA-POSS at different proportions, and the cure kinetics were investigated by nonisothermal differential scanning calorimetry (DSC) technique. The results show that UPR, the methyl methacrylate and EA-POSS have very good compatibility and can co-cure in free radical polymerization. The curing reaction can be described by a two-parameter autocatalytic Šesták-Berggren (S-B) model and kinetic equations are obtained. The reaction rate is increased with the addition of EA-POSS. The electrical properties of fiberglass-reinforced laminates, thermal stability and dynamic mechanical properties of EA-POSS/UPR nanocomposites were determined. The results indicate that these properties are all modified after EA-POSS is added to the UPR. The mechanical loss peak temperature Tp increases by about 30–35°C and the initial decomposition temperature increases by about 15°C.