Xu G, Shi WF, Gong M, Yu F, Feng JP (2004a) Curing behavior and toughening performance of epoxy resins containing hyperbranched polyester. Polymers for Advanced Technologies 15(11), 639-644. [In English]
Web link: http://dx.doi.org/10.1002/pat.520
Keywords:
hyperbranched; polyesters; epoxy resins; curing of polymers; toughness; thermooxidative degradation; photopolymerization; polyurethane; phosphorus;
Abstract: The effects of the hyperbranched polyester with hydroxyl end groups (HBPE-OH) on the curing behavior and toughening performance of a commercial epoxy resin (diglycidyl ether of bisphenol A, DGEBA) were presented. The addition of HBPE-OH into DGEBA strongly increased its curing rate and conversion of epoxide group due to the catalytic effect of hydroxyl groups in HBPE-OH and the low viscosity of the blend at curing temperature. The improvements on impact strength and critical stress intensity factor (or fracture toughness, K-1c) were observed with adding HBPE-OH. The impact strength was 8.04 kJm(-1) when HBPE-OH reached 15wt% and the K-1c value was approximately two times the value of pure epoxy resin when HBPE-OH content was 20 wt%. The morphology of the blends was also investigated, which indicated that HBPE-OH particles, as a second phase in the epoxy matrix, combined with each other as the concentration of HBPE-OH increased. Copyright (C) 2004 John Wiley Sons, Ltd.
