염수환경에 의한 UPN139 탄소/에폭시 복합재 물성치 변화 연구

Experiments were performed to investigate the effect of salt water on the mechanical properties of UPN-139 carbon-epoxy composite after 0, 1, 3, 6, 9 and 12 months immersion in 3.5% salt water. Waterproof painting and sealing tape were applied to protect the water absorption on the both cutting sides and taps of specimens. Test results show that while the tensile properties in fiber and matrix direction did not decrease considerably until 12 months of immersion, shear strength and modulus decreased gradually from nine months of the immersion. The reduction of shear strength and modulus were 9.5% and 10.8% of the values of dry specimens without exposure to salt water, respectively .