GAS SORPTION AND TRANSPORT-PROPERTIES OF THE MEMBRANE FROM POLYCARBONATE CO-III ACETYLACETONATE BLEND/

Various amounts of cobalt(III) acetylacetonate (Co(acac)(3)) were adde d to a polycarbonate (PC) membrane to enhance its oxygen enrichment ab ility. As high as 20 wt% of Co(acac)(3) can be blended with polycarbon ate to form a homogenous membrane and a significant improvement of oxy gen selectivity was observed, Both the solubility and diffusivity rati o of oxygen to nitrogen increased with the increase of Co(acac)(3) con tent. But the data indicated that the increase of oxygen/nitrogen sele ctivity by introducing Co(acac)(3) was mostly due to the increase of d iffusivity selectivity of the membrane. The carbonyl functional group of polycarbonate has a distinct absorption at 1780 cm(-1) in the FTIR spectra. This peak splitted after the addition of Co(acac)(3) and the absorbance of the second peak increased with the amount of Co(acac)(3) added. The spilt of the carbonyl peak in the FTIR spectra implied tha t a specific interaction existed between polycarbonate and Co(acac)(3) . It was suspected that the improvement of solubility selectivity was due to this interaction. The O-2/N-2 selectivity measured at 25 degree s C and 1 atm was 8.4 while the flux was 49 (10(-10) cm(3) cm/cm(2) a) . The O-2/N-2 selectivity was expected to be higher at a lower operati ng upstream pressure and the oxygen flux could be increased by operati ng at a higher temperature.