Strength Deterioration and Degradation Mechanism of Glass Chopped Reinforced Plastics in Water Environment

Abstract

In this paper the effect of water environment on the fracture toughness of glass chopped strand reinforced plastics is discussed. Fracture toughness tests were performed by using compact tension specimens of the composite immersed in distilled water for 10 days to 1.5 years. Acoustic emission signals were detected during the tests. The observation of fracture surfaces by a SEM and the quantitative analysis of dissolution elements from glass fibers by an atomic absorption spectrophotometer were also carried out to clarify the degradation mechanism of the composite. It was found that (1) the fracture toughness obtained by the acoustic emission method decreases as the immersion time is longer ; (2) the decrease of the fracture toughness is caused by the degradation of the bonding interface between glass fibers and the resin matrix and the weakening of glass fibers due to the dissolution of the elements in water.