YOUNG MODULUS OF TRANSCRYSTALLINITIES IN SEMICRYSTALLINE THERMOPLASTIC COMPOSITES

In a fiber/semicrystalline polymer system, interphasial transcrystalli nities might form between the fibers and the matrix bulk that is compo sed of spherulites. By using an analogy method, the Young's modulus E( T) of transcrystallinities in their growth direction was predicted by a well-known composite modeling theory. It is shown that E(T) is a fun ction of the polymeric lamellar morphology and crystallinity. It is hi gher than the Young's modulus E(s) of the bulk spherulites and positiv ely affects the stiffness of the materials in which the transcrystalli nities are formed. The study was focused on poly(ether ether ketone) ( PEEK) but with polyethylene (PE) as a comparison. Also, it is demonstr ated the various possibilities of the value E(T) and the ratio E(T)/E( S) for different polymeric matrices depending on their amellar moduli and the amorphous-phase ones. (C) 1994 John Wiley & Sons, Inc.