Crystallization and Mechanical Properties of Continuous Carbon Fiber Reinforced Polyether-ether-ketone Composites

The effect of two different continuous carbon fibers (CCF1 and CCF2) with different material properties on structure-properties of continuous carbon fibers reinforced polyether-ether-ketone prepreg tapes (CCF/PEEKPT) prepared by a wet powder impregnation process were investigated. The effects of fiber content on the tensile properties, dynamic mechanical behavior, crystallization melting behavior and fracture morphology of prepared prepreg tapes were performed by the dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and scanning electron microscope (SEM) etc. The results showed that, the tensile strength of CCF1/PEEKPT increased with increasing of the carbon fiber content within 50-75 wt%. Meanwhile, the tensile strength of 50-65 wt% CCF2/PEEKPT had the same change trend, but then decreased when the fiber content of composites was higher than 65 wt%. The storage modulus (E) of composites increased with adding content of carbon fiber. The composites still maintained high deformation resistance when the temperature rose to 290 degrees C. Compared with pure PEEK, the crystallinity and crystallization rate of the composites both increased with the occurrence of fiber inducing PEEK crystallization, but the crystallization onset temperature, crystallization temperature and melting temperature of CCF/PEEKPT moved to low temperatures with adding of fiber content. In general, these observations suggested that CCF hindered the movement of the polymer chain segment and constrained the spherulites growth of PEEK for CCF/PEEKPT.