Abstract: The hygrothermal properties of carbon fiber reinforced bismaleimide (BMI) resin composite laminates are investigated under the influence of different factors including hygrothermal condition, carbon fiber type and preparing method of prepreg. Moisture absorption, dynamic mechanical property, flexural property and fracture morphology are adopted to analyze the effects of various factors on hygrothermal properties of composites. Results show that under different hygrothermal conditions, there are only physical changes in the composites and no obvious chemical changes happen. The domestic T300 carbon fiber/BMI resin composite has lower hygrothermal stability, which is in accordance with its poor interfacial adhesive property. The composite prepared with solution method prepreg has lower hygrothermal property than that prepared with melt method prepreg, indicating that solvent has significant effects on the interfacial and hygroscopic properties of BMI resin composites.

Key words: composite laminate, BMI resin, carbon fiber, hygrothermal property