Poly ether ether ketone(PEEK) is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. It has a high glass transition temperature (145°C), high melting point (340°C) and a high continuous service temperature with the advantages of easy process ability by injection molding and other techniques common to thermoplastic polymers[1]. The mechanical properties of thermoplastic matrix composites depend significantly on the microstructure parameters, such as the degree and type of crystals. There are several indications that slow-cooled or annealed materials, which have a fully developed crystalline structure, exhibit better mechanical properties. Likewise the presence of crystallinity was shown to influence the mechanical performance through its effect on fiber/ matrix bonding and on the stress transfer mechanism.

In this study, we observed the crystallization effects after annealing treatments on the mechanical performance of PEEK/Carbon fiber composites prepared by AFP(Automated Fiber Placement) process. The result indicated that the properties of the PEEK/carbon composites were significantly improved by the Post-thermal treatment. Also, the property improvement of PEEK/carbon composites strongly depended on the various treatment method.