Characterization and properties of new silicone-containing epoxy resin

Abstract

A new epoxy monorner, triglycidyloxy phenyl silane (TGPS) has been synthesized. By curing of TGPS, Epon 828 and DER 732, with 4,4-diaminodiphonyl methane (DDM), the curing rate and conversion efficiency of these epoxy resins are in the order of TGPS > Epon 828 > DER 732. In the mixed epoxy system of TGPS/Epon 828/DDM, homogenous products are obtained from all proportions. In addition, the glass transition temperature of the blend decreases with increasing amount of TGPS from 140 to 100 degrees C. By using TGA in a Nz environment, the onset decomposition temperature of silicone-containing epoxy resin system of TGPS is 80 degrees C lower than that of Epon 828, and the decomposition of TGPS is a two-stage process with maxima weight loss rates at 330 and 430 degrees C, respectively. The first stage involves the breaking of the silicons-containing group in TGPS and the second-stage is carbonization. In the second stage of carbonization, the temperature for maximum weight loss rate is 15 degrees C higher than that of the Epon 828 in the first stage. This result indicates that the silicone-containing group is in favor of the carbonization mechanism and the solid char yield at 800 degrees C for TGPS is 40 wt%. Based on EDX analysis on the surface elements, the presence of Si and C is indicative of the above observation. In addition, the result by using TGA in an air environment shows that the silicon-containing carbon residue is superior in preventing oxidative burning. The high limiting oxygen index (LOI) of TGPS at 35 is considered as an excellent flame retardant in the epoxy system. (C) 2000 Elsevier Science Ltd. All rights reserved.