A Study of the Change in the Surface Layer Structure of Microfiltration Films of MMPA, MPS, and MFFK

This work has investigated changes in crystallinity and amorphism in the surface layers of commercial microfiltration films. Experimental studies of supramolecular formations and changes in the structure of microfiltration films were carried out by differential scanning calorimetry and X-ray diffractometric measurements in reflection geometry in the region of large angles. In the process of water swelling of semipermeable films of the MMPA, MPS, and МFFK types, a change in the structure of the lattice of the films is observed due to an increase in the interatomic distance, that is, the size of the pore diameter is likely to change throughout the structure of both the active layer and the film substrate. The observed changes in the supramolecular structure of the films upon swelling occur to a greater extent due to the disordering of macrochains in all layers of the films. The decrease in the degree of crystallinity of the films upon sorption of water is most likely associated with the redistribution of the ratio between the number of perfect crystalline phases in polyamide crystallites with different values of the enthalpy of melting.