MISCIBILITY AND CRYSTALLIZATION BEHAVIOR OF POLY(ETHER ETHER KETONE) POLYIMIDE BLENDS/

The miscibility and crystallization behaviour of the blends of poly(et her ether ketone) (PEEK) with two thermoplastic polyimides (PI), PEI-E and YS-30, prepared by solution blending were studied by the use of s mall-angle X-ray scattering (SAXS), differential scanning calorimetry (d.s.c.) and polarizing microscopy techniques. The results obtained sh ow that PEEK/YS-30 is miscible, while PEEK/PEI-E is partially miscible only in the composition range with PEI-E content up to 20 wt%. The cr ystallization behaviour of PEEK in PEEK/PI blends depends on the cryst allization condition of the blend sample as well as the chemical struc ture and the content of the PI added. Our SAXS results indicate that t he segregation of PI molecular chains during crystallization of PEEK c hains in the blends is interfibrillar for PEEK/PEI-E blends, but inter lamellar for PEEK/YS-30 blends. The compatibility and the crystallizat ion behaviour are discussed in terms of charge transfer interaction be tween PI and PI molecules and between PI and PEEK molecules.