【Abstract】 New polymeric membrane materials--polyvinyl amine (PVAm) with different primary amine contents were synthesized By covering polyacrylonitrile(PAN) ultrafiltration membranes with PVAm, the PVAm/PAN composite membranes for CO 2/CH 4 separation were prepared The composite membranes containing more primary amino groups have higher selectivity for CO 2/CH 4 The cross linking of acid or glutaradehyde could improve the gas permselectivity of the composite membranes With decreasing CO 2 content in the feed gas, the CO 2/CH 4 separation factor increased When the feed gas was 25%(vol) CO 2 and 75%(vol) CH 4, the CO 2 permeation rate was 4 1×10 -9 cm 3(STP) ·cm -2 ·Pa -1 ·s -1 , and the CO 2/CH 4 separation factor was 180更多还原