MORPHOLOGICAL ASPECTS OF THE INTERFACE IN THE PEEK-CARBON FIBER SYSTEM

Although high modulus PAN based carbon fibers (HMS) induce transcrystallinity in PEEK and a wide variety of other semi-crystalline polymers, the interfacial strength is lower than PEEK in contact with low modulus carbon fibers (AS4) where transcrystallinity is not induced. In the PEEK/HMS system, crystalline lamellae were found to be oriented edge-on to the fibers, while in AS4 they were oriented flat-on, reflecting the difference in surface energies between the two fibers. The intrinsic effect of transcrystallinity on the fiber matrix interaction is therefore obscured when the chemistry of the interaction varies.