Cross-linking has been regarded as an effective method to improve the selectivity of gas separation membrane.However,cross-linking also showed a tendency to decrease the gas permeance.In this study,cross-linked vinylamine-co-vinylalcohol/ polysulfone (VAm-co-VOH/PSf) composite membranes with improved gas permselectivity were developed using including maleic anhydride (MA) and glutaraldehyde (GA) as cross-linking agents.In these membranes,amino group can react reversibly with CO2 and facitilate the CO2 transport.The membrane morphologies and thermostability was studied by SEM and TGA respectively.The gas permeance and CO2/N2 selectivity were investigated.The result showed that the GA cross-linked membrane has higher CO2/N2 selectivity but lower CO2 permeance comparing with the uncross-linked membrane.The MA cross-linked membrane possessed both higher CO2/N2 selectivity and higher CO2 permeance.The CO2 permeance and CO2/N2 selectivity of the MA cross-linked membrane reach to 224(GPU) and 78 respectively.As cross-linking agents both GA and MA can result in denser membrane structure,which leads to higher CO2/N2 selectivity.In the cross-linking reaction,GA reacts with the amino groups leading to the decrease of amino group content.Therefore,the membrane cross-linked with GA has lower CO2 permeace.For MA,it can react with the –OH group to form ester group.The membrane cross-linked with MA has higher amino group content because of that the cross-linking reaction does not consume the amino group.Therefore,the MA cross-linked membrane has higher CO2 permeance.The TGA analysis results indicate that the MA cross-linked membrane has better thermal stability than GA.