Abstract
The stress corrosion characteristics of uniaxial glass fibre reinforced thermosetting resin composites have been examined in Hydrochloric acid at room temperature and 80 °C. A simple technique based on linear elastic fracture mechanics (LEFM) is presented for characterising crack growth in these materials subjected to hostile acidic environments. The environmental stress corrosion cracking is investigated both for different types of resin and different types of glass fibre reinforcements. Two matrices were used: Bis-A epoxy vinyl ester resin (based on Bisphenol-A epoxy resin) and novolac epoxy vinyl ester resin (based on epoxidised novolac resin). Two glass fibre types were employed: standard E-glass fibre and “R”, a special type of E-glass with superior acid resistance. Model experiments using a modified double cantilever beam test with static loading have been carried out on unidirectional composite specimens in 1M Hydrochloric acid solution at room temperature and 80 °C. The rate of crack growth in the specimen depends on the applied stress, the temperature and the environment. Consequently, the lifetime of a component or structure made from GRP, subjected to stress corrosion conditions, could be predicted provided the dependence of crack growth rate on stress intensity at the crack tip is known. Scanning electron microscopy studies of the specimen fracture surfaces have identified the characteristic failure mechanisms. The most important findings of this work is that the selection of epoxy vinyl ester resins reinforced with “R” fibre exhibited superior resistance to crack growth at 80 °C compared to similar E-glass reinforced composites at room temperatures.
