preparation of microporous membranes from blends of poly(phenylene oxide) and poly(p-phenylene oxide-sulfone) or polysulfone

The surface morphology and performance of modified and unmodified PPO membranes were examined in addition of different nonsolvent additives. The final morphologies of the membranes changed according to the type of casting nonsolvent; thus, their transport properties were also affected by the parameter. It was observed that there were two types of nodules identified as merged and discrete. It was found that the membranes containing smaller or merged nodules resulted in higher pure gas permeance ratios for O2/N2. In addition, the highest pure O2/N2 permeance ratio was for 2-ethyl-1-hexanol and the lowest was for 2-propanol.