Infrared Spectral Imaging of the Interphase of Epoxy-Glass Fiber-Reinforced Composites under Wet Conditions

Abstract

Infrared imaging was utilized to analyze the behavior of epoxy-glass fiber composites when exposed to moist conditions. With the use of mapping subtraction, the differences in the water uptake were revealed when different types of glass fibers were used. Composites prepared with as-received glass fibers exhibit the highest water uptake at the interphase as opposed to those prepared with silane-treated glass fibers, which exhibit the lowest uptake. Moreover, the epoxide deformation band was examined in order to analyze the effect of water on the curing of the composites. Water was found to catalyze a polymerization reaction at the interphase, but only if a certain level of water concentration is present is the above phenomenon detectable.