Research on Properties of 450°C Resistant Polyimide Composites

Carbon fiber/polyimide composites were prepared by high temperature molding process with carbon fiber, 450 °C resistant polyimide resin and related additives as raw materials. Effects of prepreg resin content, porosity and post-treatment temperature on properties of composites were studied, and fracture shape was analyzed. Results show that high temperature shear properties of carbon fiber can be improved by more than 50% after removing sizing agent, and mechanical properties of composites are the best when the resin content of prepreg is (30 to 40)%. Retention rate of mechanical properties of composites is more than 90% when porosity is less than 1.5%. And mechanical properties decline sharply when porosity is greater than 2%. Carbon fiber/polyimide composites have good high temperature resistance below 450°C, and mechanical properties of composites can be improved to a certain extent after treatment at room temperature to 300°C. Fracture morphology analysis shows that high temperature mechanical properties of composites depend on heat resistance of resin and matching between resin and fiber.