STRUCTURAL AND MORPHOLOGICAL FEATURES OF THE SYNDIOTACTIC POLYSTYRENEETHYLBENZENE COMPLEX/

The delta-phase of the syndiotactic polystyrene/ethylbenzene system, a s formed by crystallisation from dilute solution, is shown to result i n a lamellar morphology, with a monoclinic crystal lattice similar to that already reported for the complex with toluene. Combined SAXS, FTi .r., d.s.c. and t.g.a. measurements show that an increase in the X-ray long period between 80 and 120 degrees C is related to solvent loss a nd decomplexation. There is also some temporary loss in helical order. SANS measurements on the delta-phase reveal negligible isotopic fract ionation. The small increase in the in-plane radius of gyration with i ncreasing molecular weight is interpreted as evidence of a sheetlike m olecular conformation, with superfolding at higher molecular weights l eading to a multiple sheet structure. On transformation to the solvent -free gamma-phase, an increase in radius of gyration results from a di splacement of crystal stems out of the delta-phase sheets. (C) 1998 El sevier Science Ltd. All rights reserved.