Processing-Structure-Property Relations in PEEK/Carbon Composites Made from Comingled Fabric and Prepreg

Abstract

Although the processability of PEEK/carbon prepreg has received much attention, the effects of processing on the microstructure and performance of the co mingled fabric system is not well known. In this paper, the effect of molding temperature, molding time and cooling rate on the mechanical performance of PEEK/carbon compos ites made from both prepreg and comingled forms are discussed. To obtain good mechanical properties of PEEK/carbon fiber composites, processing must be carried out at a temperature sufficiently high to destroy the previous thermal history of the PEEK matrix. While the fiber/matrix interaction in the prepreg system does not seem to be af fected by the thermal processing conditions, this interaction in the comingled system must be created during the molding process. Fiber/matrix adhesion in the comingled system depends on the molding temperature, residence time at melt temperature as well as cooling rate. This is probably a result of several complex mechanisms such as matrix adsorption on the fiber surface, matrix degradation leading to chemical bonding and interfacial crystallization.