OXYGEN NITROGEN SEPARATION BY PLASMA CHLORINATED POLYBUTADIENE/POLYCARBONATE COMPOSITE MEMBRANE/

The surface of a polybutadiene (PB)/polycarbonate (PC) composite membr ane was plasma-modified by CHCl3 to enhance its oxygen/nitrogen select ivity. The selectivity of the composite membrane was significantly imp roved after plasma chlorination. The degree of chlorination on the sur face of this composite membrane surface was controlled by the supplied power for plasma and the plasma treating time. The chlorination was v erified by infrared spectroscopy (FTIR-ATR) and ESCA analysis. The CHC l3 plasma treated membrane had an oxygen/nitrogen selectivity of 7.5 a nd a gas permeation flux of 0.3 GPU. The selectivity enhancement was a ttributed mostly to the alteration of the physical structure on the me mbrane surface rather than the chemical effect introduced by chlorine. It was found that the surface hydrophilicity of the plasma treated me mbrane increased after long period of storage. Surface swelling by wat er vapor may be the reason for the selectivity degeneration.