Structural Transformations in Composite Nanofiltration Films Caused by the Action of Excess Pressure

Abstract

Samples of original and working porous composite nanofiltration membranes were investigated by xray scattering, thermal analysis, and study of the specific flow rate and retention coefficient. It was established that mechanical loading due to excess pressure of 1.5 MPa in the OFAM-K membranes leads to conformational changes in the phenylone C-4 macromolecules in the crystalline and amorphous intercrystalline phases, where the calculated degree of crystallinity decreases from 49 to 36%. Investigations by differential-scanning calorimetry indicate homogeneous crystallites with a thermal effect of 7.87 kJ/kg are formed in the working sample of the membrane. The working sample of OPMNP membrane undergoes polymorphous rearrangement of the crystalline phase with a change in the dimensions of the crystalline cell in the direction of the crystal axis (c) and with increase of crystallinity from 44 to 55%, while the amorphous phase becomes looser.