Chapter 3 - Polyimide Matrices for Carbon Fiber Composites

Abstract

This chapter deals with the polyimide matrix resins for advanced carbon fiber composites, especially the chemical structures design, synthesis, high-temperature properties and applications. Polyimide/carbon fiber composites (Cf/PI) are currently the most thermal-resistant lightweight polymeric composites with long-term servicing temperature of as high as 400°C and short servicing temperature of as high as 500°C. The Cf/PI composites have been extensively used as primary structural and sub-structural lightweight components in aero-engines, aerospace vehicles and propulsion systems etc. Polyimide matrix resins have been playing the key role in fabrication of composite components, not only determine the component’s thermal servicing and mechanical properties, but also its processing methods and quality. However, it is very difficult to design and synthesize polyimide matrix resins for high temperature composite component fabrications, because the matrix resins are required to have not only enough thermal and mechanical properties, but also appropriate melt processability. The chemistry of the reactive endcapped thermoset polyimide resins is first introduced. The design, preparation, structures and properties of the NA-endcapped thermoset polyimides for 316 and 371°C applications are discussed in detail, and the chemistry, structure and property relationship of PE-endcapped oligoimides for different processing methods such as autoclave and RTM are also systematically discussed. Finally, the combined properties of Cf/PI composites fabricated by autoclave and RTM processing are described.