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Curing behavior, thermal, and mechanical properties of epoxy resins cured with a novel liquid crystalline dicarboxylic acid curing agent
Author(s) -
Sinh Le Hoang,
Trung Nguyen Ngoc,
Son Bui Thanh,
Shin Seunghan,
Thanh Dinh Tan,
Bae JinYoung
Publication year - 2014
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.23585
Subject(s) - epoxy , materials science , bisphenol a , epichlorohydrin , curing (chemistry) , composite material , thermal stability , char , fracture toughness , toughness , pyrolysis , organic chemistry , chemistry
A novel di‐carboxylic acid curing agent (DACA) was successfully synthesized and cured with three different epoxy resins: glycidyl end‐capped poly(bisphenol‐A‐ co ‐epichlorohydrin) (pDGEBA, M n = 377), N , N ‐diglycidyl‐4‐glycidyloxyaniline (TGAP), and 4,4′‐methylenebis( N , N ‐diglycidylaniline) (TGDDM). The cured epoxy exhibited excellent thermal stability, which was indicated by high initial degradation temperature ( T id ) and char yield. The T id values of cured epoxy were in the range of 327–338°C, and the char yields increased with increasing epoxy functionality. The char yields of cured DACA/pDGEPA, DACA/TGAP, and DACA/TGDDM samples were 21.1, 60.4, and 66.9%, respectively. In addition, the cured epoxy samples also showed low coefficients of thermal expansion and high storage moduli ( E ′), which were around 60 ppm/°C and 2800 MPa, respectively. The failure surfaces were ductile and rough, so the cured epoxy samples are expected to have high fracture toughness and impact strength. POLYM. ENG. SCI., 54:695–703, 2014. © 2013 Society of Plastics Engineers