The d phase of syndiotactic polystyrene/ethylbenzene has previously been shown to involve a sheet-like arrangement of crystal stems, with superfolding at higher molecular weights. SANS measurements have been made using tilted samples in order to separate in-plane and out-ofplane radii of gyration. Use of intensities from the whole area of the detector allows the determination of these quantities with good precision. Comparison between the out-of-plane radius and the long spacing determined from small angle X-ray measurements shows close agreement for the lower molecular weight (M̄ w ¼ 42 700) in both d and g phases, while R z is a factor of 2 larger for the higher molecular weight (M̄ w ¼ 124 500). This indicates that each molecule occupies a single lamella at the lower molecular weight and, on average, two lamellae at the higher one, in both d and g phases. This provides clear evidence of tie molecules at the higher molecular weight, and also implies that the d to g phase transition only involves a reorganisation of chain segments within those lamellae which originally contained the molecule.
Посилання на статтю:
Molecular dimensions in the d and g phases of syndiotactic polystyrene, using small angle neutron scattering / Stéphane Moyses, Stephen J. Spells // Polymer. – 1999. – N 40. – P. 3269–3274.
