Polypyrrolones for membrane gas separations. I. Structural comparison of gas transport and sorption properties

Despite efforts by the membrane community to develop polymeric materials wi th improved O-2/N-2 separation performance, limited progress has occurred f or almost a decade. Molecular sieving media, which can exhibit gas separati on properties superior to polymers, tend to be brittle and uneconomical to produce for large-scale membrane separation processes. Considering this, th e polymer structures investigated in this work were designed to mimic aspec ts of the structure of molecular sieving media such as zeolites and carbon molecular sieves while maintaining the processability associated with polym ers. Significantly attractive gas separation material properties were obtai ned using hyper rigid polypyrrolone copolymers with controlled packing disr uptions between flat, packable segments. The gas transport properties in th e materials changed dramatically as a result of different average interchai n spacing. Moreover, all of the polypyrrolones studied in this work. exhibi ted performance lying on or above the existing O-2/N-2 upper bound trade-of f line between permselectivity and permeability. These results, therefore, may point the way to a new cycle of membrane materials improvements for gas separations. (C) 1999 John Wiley & Sons, Inc.