Hygrothermal effects on painted and unpainted glass/epoxy composites - Part A: Moisture absorption characteristics

Moisture diffusion behaviour of glass/epoxy composites coated with a polyurethane base paint and those without the paint were studied on immersion in water at 323 K. Neat resin castings of the epoxy resin system were also studied for comparison. The composite specimens with paint showed lower moisture absorption values than those of the unpainted specimens subjected to the same immersion conditions. The diffusion parameters obtained from the experiment conducted up to saturation limits agreed well with the data computed using moisture absorption programme (M8 gain) proposed by G. S. Springer. The mixture rule for moisture absorption was also verified for the weight fraction studied. Further, Fickian correlation was found to exist in all the cases