Abstract
In this work, polyepoxide network based on an aliphatic amine hardener were cured under different curing temperatures and their water sorption characteristics was systematically investigated as function of cure conditions. Attention was focused on the analysis of equilibrium properties, swelling behaviour and thermomechanical properties. For the undercured systems (epoxide conversion around 0.90), additional crosslinking reactions take part during water immersion, even at 20 °C. This effect was found to be mainly related to plasticizing of the network by water molecules. Local dynamics and plasticization effects were also monitored by dynamic mechanical analysis (DMA). The changes in the glass transition for the two well-crosslinked epoxies were greater than those predicted by considering the free volume changes only. The β process was significantly affected by the absorbed water. A decrease of the average relaxation time with moisture uptake was observed. The disruptions of the α and β relaxations were found to be reversible after re-drying of the wet material for the nearly fully cured epoxies. The fully crosslinked network was found to absorb slightly more water and at a greater rate than a slightly less crosslinked network (conversion around 0.98). This anomalous behaviour was analysed and a tentative explanation was presented in this paper.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
