Supramolecular formations and structural transformations in porous polyethersulfone/polyamide film materials

Abstract

Structural properties of an ESPA-type polyethersulfone/polyamide film is studied by the method of X-ray diffractometry in the region of wide angles, and it is established that there is a slight decrease in the X-ray degree of crystallinity (DC) in the process of its water swelling. Data obtained by the method of smallangle X-ray scattering (SAXS) indicate that the sorption space of the amorphous phase of the ESPA film is formed, in fact, by three kinds of pores with different surface morphology. The pores of a smaller radius are capillaries with a smoother surface, and the large pores are channels with a “dissected” surface. Differential scanning calorimetry (DSC) studies reveal a bimodal endothermic peak at temperatures of 250 and 254°C, which is attributable to the melting of crystalline phases. A decrease in the degree of crystallinity upon the water sorption is associated with redistributing the proportion between structurally perfect crystalline phases with different melting enthalpy values in the crystallites of polyamide 6.6.