RELATIONSHIP BETWEEN MECHANICAL AND DYNAMIC MECHANICAL PROPERTIES AND WATER ABSORPTION OF NAVAL COMPOSITES

摘要

The effect water on mechanical and dynamical-mechanical properties of unsaturated polyester, vinyl-ester and epoxy resins/glass fibers composites was investigated. Studies were carried out at several temperatures. The behavior depends on the difference between the glass transition temperature and the bath temperature. The diffusion coefficient increased with the temperature. Mechanical properties decreased as a consequence of the poorer fiber/matrix interfacial adhesion (studied by SEM) which also decreased as temperature increased. The effect of fibre arrangements was also investigated. For cycling process, the water absorbed and the diffusion coefficient were lower in the first cycle because the cracks created in this stage and during drying leads to higher voids content; this effect was remarkable for composites and at higher temperatures. Dynamicalmechanical properties were modelled.