Impact of polar groups concentration and free volume on water sorption in model epoxy free films and coatings
By G. Bouvet and Nguyen Dang and S. Cohendoz and X. Feaugas and S. Mallarino and S. Touzain
Published in Progress in Organic Coatings
2016
Abstract
The water sorption characteristics have been determined for two model epoxy systems based on the \DGEBA\ resin and two amine hardeners (TETA and DAMP). A particular attention was paid to the curing protocol to control the macromolecular architectures. Using FTIR, \DSC\ and \DMTA\ measurements, it was demonstrated that both network microstructures differ mainly in the polar groups density, the potential crosslinking nodes and the free volume. DGEBA/DAMP system presents a higher free volume fraction and a lower polar groups concentration compared to the DGEBA/TETA system. Gravimetric measurements on free films and \EIS\ experiments onto coated steel Q-panels were carried out to follow the water sorption kinetics at different temperatures (30, 40, 50 and 60