Processing and properties of new high‐temperature, lightweight composites based on foam polyimide binder

Abstract We report a method for making novel, lightweight (ρ = 0.3–1.1 kg/dm³) polymer composites based on high‐temperature foam polyimide binder, carbon fibers, and organic fibers. The density and mechanical properties of the foam composite can be varied over a relatively wide range, depending on the volume contents of the fiber and air pores. The resin's high glass transition temperature of 260°C, coupled with the high thermal stability of carbon or polyimide fibers, contributes to its excellent retention of mechanical properties at elevated temperatures. The temperature at the beginning of weight loss is not lower than 570°C and depends on the kind of fiber felt. The combination of excellent thermal and specific mechanical properties of foam composites together with exceptional thermal stability and processability on conventional molding equipment can provide unusual performance for the new design of advanced materials and structures.