Structural aspects of poly(thiodiethylene terephthalate) investigated by X-ray powder diffraction

The full-profile refinement of X-ray diffraction patterns was used to investigate two poly (thiodiethylene terephthalate) (PSDET) samples with different thermal history in order to thoroughly analyze their polymorphic aspects. In each sample, a crystalline (alpha or beta) and a microcrystalline (alpha' or beta') phase were identified together with an amorphous component. The crystal structures of all the ordered phases were determined. The data indicated an appreciable difference between the two crystalline forms, while the microcrystalline were rather similar. The results reported in this paper agree with the hypothesis that the polymorphic and morphological aspects of PSDET have to be correlated with the order degree and reorganization of crystallites and microcrystallites.