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Curing behavior and toughening performance of epoxy resins containing hyperbranched polyester
Author(s) -
Xu Gang,
Shi Wenfang,
Gong Ming,
Yu Fei,
Feng Jianping
Publication year - 2004
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.520
Subject(s) - epoxy , diglycidyl ether , materials science , curing (chemistry) , bisphenol a , epoxide , toughening , izod impact strength test , composite material , toughness , hydroxyl value , catalysis , organic chemistry , polyurethane , chemistry , ultimate tensile strength , polyol
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 kJ m −1 when HBPE‐OH reached 15 wt% 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 © 2004 John Wiley & Sons, Ltd.