Long term aging and failure behaviors of carbon fiber reinforced polymer composites in simulated marine environments

Carbon fiber reinforced phenolic resin composite (CF/S-157) and carbon fiber reinforced epoxy composite (CF/TDE-85), which are widely used at present, were selected to carry out the salt spray aging, hydrothermal aging and salt water immersion environmental test in laboratory. Based on various mechanical properties (tensile strength, flexural strength, compressive strength and interlaminar shear strength), the corrosion behaviors of the composite materials were studied. The changes of molecular segments and functional groups of resin matrix in various aging environments were analyzed by attenuated total reflection flourier transformed infrared spectroscopy (ATR-FTIR), and the failure modes of various matrix resins were obtained. The failure mode of resin/fiber interface was identified based on the characterization of SEM and ultrasonic C-scanning testing and imaging system. The effects of various aging methods on glass transition temperature T_g and thermal mass loss of composites were analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results show that the deterioration severity order of the three aging methods is hydrothermal aging, salt spray and salt water immersion. The corrosion characterization, failure mechanism and failure mode of the composites in simulated marine environment are obtained, which lays a foundation for environmental adaptability evaluation and service life prediction of high-performance resin matrix composites.