Journal of Polymer Science Part B: Polymer Physics, Vol.34, No.17, 3055-3061, 1996
Short-Range Order in Some Polymer Melts from X-Ray-Diffraction
Wide-angle X-ray diffraction measurements were performed on polymer melts of isotactic and syndiotactic polypropylene (IPP and SPP), poly(ethylenepropylene) (PEP), polystyrene (PS), polyisobutylene (PIE), and polyethylene (PE), to study the dependence of the short-range structure of polymer liquids on chain architecture. Total structure functions, which comprise intra- and intermolecular contributions, were derived from the scattering data. The trivial Fourier components of the intramolecular structure (C-C similar or equal to 1.54 Angstrom and C-C-C similar or equal to 2.55 Angstrom) were subtracted from the total structure functions. The remaining functions contain only those intramolecular contributions dependent on the chain’s conformational degrees of freedom, plus the intramolecular contributions. The structural differences between the polymers in momentum space are discerned only when the trivial components are subtracted. This subtraction also reduces the effects of truncation errors on Fourier transformation to real space. The short-range structure of PIE appears very different compared to all the others, which correlates with anomalies in a number of physical properties for this polymer.
Keywords:NEUTRON-SCATTERING DATA;MOLTEN POLYETHYLENE;LOCAL-STRUCTURE;RADIAL-DISTRIBUTION;CHAIN;CRYSTALLINE;MODELS;THERMODYNAMICS;POLYSTYRENE;LIQUIDS