Crystal structure of poly(p-phenylene sulfide): A refinement by X-ray measurements and molecular mechanics calculations

Samples of poly(p-phenylene sulfide) obtained by different thermal and/or m echanical treatments are found to exhibit the same crystal structure. Confo rmational and packing analysis performed by molecular mechanics have given the lowest energy conformation of the polymer chain in the crystal state an d the lowest energy crystal structure. The intensities of the observed refl ections measured by a powder diffraction profile have been compared with th e calculated intensities for different models of chain conformations and cr ystal structures. The lowest discrepancy index between calculated and obser ved intensities is obtained for a structure in very good agreement with tha t postulated by molecular mechanics.