Flexural Property and Mode I Interlaminar Fracture Toughness of Plain Woven Carbon Fiber Reinforced Plastics after Water Absorption and Freezing

Abstract

In this study, the effects of water absorption and freezing on flexural property and mode I interlaminar fracture toughness of Carbon Fiber Reinforced Plastics (CFRP) were investigated. Plain woven carbon fiber was used as reinforcement. Epoxy resin was used as matrix. Water absorption test was conducted at 90°C for 24, 100, 250 and 500 hrs. After water absorption, the specimens were kept under-15°C for 24 hrs. Static three point flexural and Double Cantilever Beam (DCB) tests were conducted after water absorption and freezing. As a result, flexural strength and mode I interlaminar fracture toughness of CFRP after water absorption and freezing decreased with an increase of immersion time. Flexural modulus of CFRP did not change after water absorption and freezing. And flexural strength and mode I interlaminar fracture toughness of frozen CFRP after water absorption were lower than those of water absorbed CFRP. From the observation using scanning electron microscope, it is understood that the water absorption and freezing affects the interfacial adhesion between fiber and matrix.