1987 年 53 巻 488 号 p. 684-692
In this paper is discussed the effect of water environment on the fracture toughness of glass chopped strand reinforced plastics. Fracture toughness tests were performed by using compact tension specimens of the composite immersed in distilled water for 10 days to 1.5 years, and acoustic emission signals were detected during the tests. The observation of fractured 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. As the result, it was found that (1) the fracture toughness obtained by 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 resin matrix and the weakening of glass fibers due to the dissolution of the elements into the water.