NEUTRON-SCATTERING STUDIES OF SYNDIOTACTIC POLYSTYRENE ETHYLBENZENE/

The neutron scattering observed from delta-phase samples of syndiotact ic polystyrene (sPS)/ethylbenzene is shown to be consistent with sheet -like arrangements of crystal stems arranged along the a direction. Ad jacent stems therefore show an alternation in helicity. Simulations ba sed on a statistical model have been used to calculate statistical par ameters, such as the probability of adjacency (P-A) for which optimum agreement is found for a value of 0.8. Radii of gyration obtained from simulations are in good agreement with experimental values. The molec ular weight range studied appears to cover the change from a single-sh eet structure to a superfolded double sheet. The same stem statistics (with P-A = 0.8) apply, irrespective of molecular weight. Scattering d ata from the gamma phase of sPS are well reproduced by a model involvi ng some movement of stems out of the planes of the sheets. (C) 1998 El sevier Science Ltd. All rights reserved.