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Water transport in graphite/epoxy composites
Author(s) -
Lee Myung Cheon,
Peppas Nikolaos A.
Publication year - 1993
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1993.070470805
Subject(s) - epoxy , materials science , composite material , absorption of water , diglycidyl ether , dynamic mechanical analysis , sorption , scanning electron microscope , bisphenol a , glass transition , adsorption , chemistry , polymer , organic chemistry
The diffusive and mechanical behavior of tetraglycidyl diaminodiphenyl methane (TGDDM) resin‐based composites and diglycidyl ether of bisphenol‐A (DGEBA) resin‐based graphite/epoxy composites were investigated during water sorption at different temperatures. The water‐absorption kinetics in both systems at 50, 70, 90, and 100°C were fitted by a Fickian diffusion model. However, a Langmuir‐type, two‐step sorption behavior was observed for water transport in DGEBA‐based systems at 50 and 70°C. Using scanning electron microscopy, internal cracks due to water absorption were found in the DGEBA‐based samples after conditioning at 90 and 100°C in water, whereas no cracks were detected in TGDDM‐based samples conditioned in water at 100°C. Ultrasonic testing did not show significant modulus or density change of the TGDDM‐based samples conditioned in water at 100°C. No significant changes of dynamic modulus or damping factor were observed for the TGDDM‐based samples redried after immersion in 100°C water, whereas slight changes were observed above 120°C for the samples containing absorbed water. However, both water‐containing and redried DGEBA‐based samples showed a decrease of dynamic modulus and an ω‐transition around 120°C. A single‐fiber fragment test revealed that the absorbed water at 80°C reduced significantly the interfacial shear strength of DGEBA/DDA resin‐AS4 fiber samples and DGEBA/DDA resin‐AU4 fiber samples. © 1993 John Wiley & Sons, Inc.