Crystal and molecular structure of the thioether-analogue of PEEK from X-ray powder data and diffraction-modelling

Colquhoun, H.M., Aldred, P.L., Hay, A.S., Hlil, A.R., Miyatake, K. and Williams, D.J. (2006) Crystal and molecular structure of the thioether-analogue of PEEK from X-ray powder data and diffraction-modelling. Polymer, 47 (2). pp. 585-590. ISSN 0032-3861 doi: 10.1016/j.polymer.2005.11.068

Abstract/Summary

Analysis of X-ray powder data for the melt-crystallisable aromatic poly(thioether thioether ketone) [-S-Ar-S-Ar-CO-Ar](n), ('PTTK', Ar= 1,4-phenylene), reveals that it adopts a crystal structure very different from that established for its ether-analogue PEEK. Molecular modelling and diffraction-simulation studies of PTTK show that the structure of this polymer is analogous to that of melt-crystallised poly(thioetherketone) [-SAr-CO-Ar](n) in which the carbonyl linkages in symmetry-related chains are aligned anti-parallel to one another. and that these bridging units are crystallographically interchangeable. The final model for the crystal structure of PTTK is thus disordered, in the monoclinic space group 121a (two chains per unit cell), with cell dimensions a = 7.83, b = 6.06, c = 10.35 angstrom, beta = 93.47 degrees. (c) 2005 Elsevier Ltd. All rights reserved.