HYDROTHERMAL AGING OF COMPOSITE-MATERIALS

The influence of water absorption and heat on the behavior of some of the most important components used in composite structure which are epoxy resins and glass fibers is discussed. Studies on blocks of unreinforced epoxy resin, used as adhesives, reveal that degradation usually occurs in environments with a concentration of water greater than 70 to 80% r.h. These effects are accelerated particularly above 70 °C. Degradation occurs by hydrolysis, by resin swelling and by cracking. Meanwhile, glass fibers resist quite well to attack by neutral water but are damaged by coming into contact with acid or alkaline environments.