Polymorphism of syndiotactic poly(p-methylstyrene): oriented samples

Possible routes for obtaining oriented fibres of the various known crystalline forms of syndiotactic poly(p-methylstyrene) are described. These routes include solvent diffusion and/or annealing on mesomorphic fibres. The X-ray fibre diffraction patterns show that form I, form II and all the clathrate forms are characterized by chains with helical s(2/1)2 conformation and repeating distance of approximate to 7.8 Angstrom, while the mesomorphic form (form IV), form III as well as a new crystalline form (form V), are characterized by chains with trans planar conformation and repeating distance of approximate to 5.1 Angstrom. Copyright (C) 1996 Elsevier Science Ltd.