Effects of Weathering on Fracture Toughness Jc and Micromechanical Properties of Unfilled and Short-Glass-Fiber-Filled Polyester, Xenoy.

Abstract

Influence of weathering on fracture toughness (Jc), microhardness (Hμ) and ultrasonic velocity (Vr) in unfilled and short-glass-fiber-filled polyester, Xenoy, has been investigated. The materials were weathered outdoors in Perth, West Australia. The specimens weathered for 6 months showed a slight increase in Jc as compared with unweathered specimens. Weathering for 11 months caused a large decrease in Jc and a slight increase in yield strength. Fracture surfaces of the specimens, however, exhibited little difference. 0n the other hand, Hμ measurements revealed a feature consistent with the trend of Jc. Vr decreased considerably in the surface layer weathered for 11 months. Weathering by artificial ultraviolet rays induced a strong increase in Hμ and a small decrease in Vr. Consequently, it was shown that the measurement of Jc in combination with Hμ and Vr is an effective way of studying weathering effects for thermoplastics.