TRANSPORT CHARACTERIZATION OF A POLYPYRROLONE FOR GAS SEPARATIONS

The gas sorption and permeation properties of a polypyrrolone step-ladder polymer have been charactertized with a variety of pure gases and one gas mixture at 35-degrees-C and for feed pressures up to 60 atm. The transport properties of the soluble prepolymer have also been characterized with pure gases up to 30 atm. The polypyrrolone shows simultaneously increased permeability and selectivity over the analogous polyimide. Wide angle X-ray diffraction measurements of the average segmental spacing of the materials and fractional free volume calculations characterize the packing of the different polymer types. Hindrance to intrasegmental motion is apparent in the polypyrrolone by the lack of a glass transition temperature prior to decomposition and by the limited plasticization by high pressure CO2. The permeability of the polypyrrolone is 89 barrers for He, 7.9 barrers for O2, and 27.6 barrers for CO2.