Processing and properties of solution impregnated carbon fiber reinforced polyethersulfone composites

Carbon fiber reinforced polymer composites are attractive because of their high stiffness and strength-to-weight ratios. In order to fully utilize the stiffness and strength of the reinforcement fiber, it is necessary to brin g the polymer matrix and the reinforcement fiber together with homogeneous wetting. In this paper, a solution processing technique and the mechanical properties of carbon fiber reinforced polyethersulfone composites were inve stigated. The polymer was dissolved in cyclopentanone and fed onto a contin uous carbon fiber tow using a drum winder. The solution-processed composite prepregs were then layed up and compression molded into unidirectional com posite panels for evaluation. The composite samples showed uniform fiber di stribution and reasonably good wetting. The longitudinal flexural modulus w as as high as 137 Gpa, and longitudinal flexural strength 1400 MPa. In addi tion, the effects of polymer grade and processing conditions on the mechani cal properties of the composites were discussed. It is suggested that the t ransverse properties and interlaminar fracture toughness could benefit from higher polymer matrix molecular weight. A careful design in the spatial di stribution of the molecular weight would be necessary for practical applica tions.