A hydrogen-permselective silicon oxycarbide membrane derived from polydimethylsilane

A novel microporous membrane has been prepared by modifying an asymmetric S IC support using polydimethyl silane (PMS). One membrane, pyrolyzed at 573 K, possesses H-2/N-2 selectivity of similar to 100 and H-2 permeance of 8.9 x 10(-8) mol.m(-2).s(-1).Pa-1 at 473 K. The other membrane, pyrolyzed at 8 73 K, has a lower H-2/N-2 selectivity of similar to 40 and lower H-2 permea nce of 4.9 x 10(-9) mol.m(-2).s(-1).Pa-1 at 473 K. Permeation in both membr anes exhibits the characteristics of activated diffusion at elevated temper atures. A higher pyrolysis temperature results in a less-permeable membrane . The support preparation and the thermal events of PMS are analyzed. The e ffects of pyrolysis temperature on membrane property are discussed.