Syntheses of silsesquioxane (POSS)-based inorganic/organic hybrid and the application in reinforcement for an epoxy resin

A new inorganic/organic hybrid material containing silsesquioxane was prepared by the reaction of caged octa (aminopropyl silsesquioxane) (POSS-NH2) with n-butyl glycidyl ether (nBGE) and 1,4-butanediol diglycidyl ether (EDGE). The copolymers of POSS, nBGE, and BDGE could be obtained with varied feed ratio of POSS-NH2, nBGE, and BDGE in the preparation. The hybrid material was added into an epoxy resin (E51) for enhancing the toughening and thermal properties of the epoxy resin. The results showed that the toughening and the thermal properties of the cured epoxy resin were greatly improved by the addition of the hybrid. The enhancement was ascribed to nano-scale effect of the PUSS structure and the formation of anchor structure in the cured network. The investigation of kinetics for the curing process of the hybrid-modified epoxy resin revealed that two kinds of curing reactions occurred in different temperature ranges. They were attributed to the reactions between amino groups of the curing agent with epoxy groups of E51 and with residue epoxy groups in the hybrid. The reacting activation energies were calculated based on Kissinger's and Flynn-Wall-Ozawa's methods, respectively. (C) 2011 Elsevier Inc. All rights reserved.