Characterization of moisture uptake and diffusion mechanisms in particle-filled composites

This study investigates moisture uptake and diffusion mechanisms in thermoset particle-filled composites for anchor applications. Two epoxy-based with low inorganic filler content one vinyl ester-based high were studied. Material characterization revealed particle size distribution, density, the occurrence of pores, composition. Moisture was monitored at different temperatures, relative humidities, water immersion up to 540 days. Based on these results a sorption isotherm, temperature dependencies, paths could be determined. A phenomenological hybrid-isotherm, consisting combination Henry's linear isotherm Type III applied describe effect fillers equilibrium uptake. Fickian observed all temperature-dependent Arrhenius relation. These observations allowed us suggest three paths: through polymer matrix, matrix-filler interfaces, matrix simultaneously.