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Identification and evaluation of progressive thermal degradation caused by carbamate formation in cyanate ester resin‐based composites
Author(s) -
Zaldivar Rafael J.,
Nokes James P.
Publication year - 2011
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.21748
Subject(s) - cyanate ester , materials science , composite material , composite number , degradation (telecommunications) , cyanate , glass transition , ultimate tensile strength , carbamate , moisture , thermosetting polymer , thermal , composite laminates , polymer , polymer chemistry , epoxy , computer science , telecommunications , chemistry , physics , organic chemistry , meteorology
The effect of moisture during cure on the mechanical and thermal performance was evaluated for a series of cyanate ester composite laminates. Data presented in our investigation show that the amount of carbamate formation is inversely proportional to the glass transition temperature ( T g ) of the cured composite and is typically localized on the outer surface plies adjacent the moisture source. Even though the majority of the composite may remains largely unaffected, the T g of the localized areas will show sharp decreases which correlate with strength as verified by flatwise tensile tests. Additionally, our test data show that performing just one T g measurement after cure will not necessarily provide a valid assessment of the state of the composite since additional degradation may occur with subsequent thermal exposure. Accordingly, a second dynamic mechanical analysis (DMA) measurement should be performed after an extended, elevated temperature, post‐treatment thereby allowing direct assessment of carbamate degradation. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.