Polymer with Intrinsic Microporosity PIM-1: New Methods of Synthesis and Gas Transport Properties

A ladder polymer with the intrinsic microporosity PIM-1 has been synthesized via precipitation polycondensation in dimethylsulfoxide and via polycondensation in N,N,N ',N '-tetramethylurea. The molecular weight characteristics of PIM-1 samples have been determined using gel permeation chromatography method. It has been shown that the synthesized polymers are characterized by a high molecular weight (similar to 90 x 10(3)) and by a bimodal molecular weight distribution; in this case, molecular weights of the high-molecular-weight fraction of polymer with the polydispersion coefficient of 2.1-2.4 are practically independent of the nature of the reaction medium. The weight content of the oligomer fraction in the obtained samples has been estimated from gel permeation chromatograms. Gas permeability coefficients of He, H-2, O-2, N-2, CO2, and CH4 for the initial films of the synthesized polymers and the films treated with ethanol have been measured by the chromatographic method at 22 +/- 2 degrees C. It has been shown that, for all samples under investigation, the gas permeability coefficients are higher than for the PIM-1 samples described previously in the literature. In this case, the gas permeability and its increase during treatment with ethanol depend on the content of the low-molecular-weight fraction in the sample.