Features of Behavior of Isotactic Polypropylene Films upon Pervaporation

The most important aspects of the large-tonnage synthesis of isotactic polypropylene represent a commercial secret. After polypropylene synthesis is completed, catalysts and other substances involved in the formation of the final product pass into the category of worthless and unknown impurities. This circumstance determines the peculiarities and difficulties of studying the behavior of impurities in polypropylene films. In this paper, the interaction of hydrophobic and hydrophilic probe liquids with polypropylene films (membranes) containing such impurities has been studied using pervaporation at different temperatures. The supramolecular structure of the polypropylene films has been successively modified by one- and two-sided hexane sorption. This procedure has decreased the apparent activation energy of permeability during pervaporation of water and acetone. It has been shown that, in the long run, the transmembrane convective pervaporation stream of acetone displaces hydrophobic and hydrophilic impurities from the polypropylene films.