Aging Performance and Mechanism of Carbon Fiber-Reinforced Bismaleamide Composites Under Natural Aging in Marine Environments

Abstract

The aging performance and mechanisms of carbon fiber reinforced bismaleimide composites under natural aging in marine environments are comprehensively investigated in this study. The prepared samples were exposed to aging under natural sunlight testing for one and a half years at the sea shores. Quasi-static tests were performed to evaluate the tensile, compressive, and in-plane shear strengths of the unaged and aged specimens. The fracture morphologies were characterized in order to reveal the aging mechanisms. The results show that the aging and decomposition of resin led to the reduction of mechanical properties. The 0° tensile, 0° compressive, 90° tensile and in-plane shear properties compared with unaged samples decreased by 4.6 %, 24.3 %, 24.7 % and 8.5 %, respectively. The microscopic, spectroscopic, and gravimetric analyses indicated that aging process mainly occurred on the surface of the specimen; the matrix degraded due to water hydrolysis, and the heat resistance of the samples decreased after aging. It was concluded that the autoclave molding method tightly combines the fibers with resin, making it more difficult for moisture to diffuse into the interior of the specimen. Based on the findings of this study, valuable insights can be made to guide the design, manufacture, and long-term durability of carbon fiber-reinforced bismaleimide composites in marine applications.

Keywords: composites, natural aging, Marine environment, mechanical properties