Water diffusion in glassy polymers and their silica hybrids: an analysis of state of water molecules and of the effect of tensile stress

In-situ, time-resolved FTIR spectroscopy along with gravimetric anal. were used to study water sorption and transport in several glassy polymeric matrixes, characterized by different levels of interaction with water, and on polymer-silica hybrids. The polymers include tetraglycidyl-4,4'-diaminodiphenylmethane epoxy, cured with either 4,4'-diaminodiphenylsulfone or hexahydrophthalic anhydride; polyimide of pyromellitic dianhydride and oxydianiline (PMDA-ODA); and the hybrids of silica (from TEOS and g-glycidyloxypropyltrimethoxysilane) and the polyimide. The time-resolved FTIR technique was coupled to a dynamical-mech. analyzer to gather information on the water sorption kinetics and thermodn. in a polymer sample submitted to stretching deformation and load. Results were modeled by coupling the mass balance and momentum balance, using a theor. approach developed for elastic matrixes and low sorbed amts. by Larche and Cahn.