天然橡胶/碳纳米管混合基质膜的气体传递特性

Gas Transport Characteristics of Natural Rubber/Carbon Nanotube Mixed Matrix Membranes

为了提高CO2分离膜的性能,将多壁碳纳米管(MWCNTs)添加到天然橡胶(NR)中制备NR/MWCNTs混合基质膜。考察了MWCNTs含量对混合基质膜机械性能的影响,研究了MWCNTs含量、进料气压力和热交联时间对NR/MWCNTs混合基质膜CO2分离性能的影响,研究了膜的耐老化性能,探讨了混合基质膜的CO2传递机制。结果表明:随着MWCNTs的增加,混合基质膜的CO2渗透系数逐渐增加,而CO2/N2选择性先增加后减少;当MWCNTs与NR的质量比为2.0%,混合基质膜的气体分离性能达到最优,其CO2渗透系数和CO2/N2选择性分别为138 Barrer和12.5.随着压力的增加,膜的CO2渗透系数和CO2/N2选择性逐渐增加。当热交联时间为24 h,在压力为2 bar下,MWCNTs与NR的质量比为2.0%的NR/MWCNTs混合基质膜的CO2渗透系数和CO2/N2选择性分别为95 Barrer和16.8;且热交联的膜比未交联的混合基质膜具有更优异的耐老化性能,这是因为MWCNTs与NR形成紧密的交联网状结构。

In order to improve the performance of CO2 separation membrane,multi-walled carbon nanotubes(MWCNTs)were added into natural rubber(NR)to prepare NR/MWCNTs mixed matrix membranes(MMMs).The effect of MWCNTs content on the mechanical properties of mixed matrix membranes was investigated.The effects of MWCNTs content,pressure and thermal cross-linking time on the separation performance of NR/MWCNTs MMMs and the anti-aging properties of the membranes were investigated.The CO2 transport mechanism of MMMs was also discussed.The results show that the CO2 permeability of MMMs increased gradually with increasing MWCNTs content,while the CO2/N2 selectivity increased firstly and then decreased.The optimal CO2 permeability and CO2/N2 selectivity of NR/MWCNTs MMM containing 2.0%MWCNTs were 138 Barrer and 12.5,respectively.Furthermore,the CO2 permeability and CO2/N2 selectivity of membrane also increased with increasing pressure.When the thermal cross-linking time was 24 h,the membrane containing 2.0%MWCNTs exhibited optimal separation performance with a CO2 permeability of 95 Barrer and a CO2/N2 selectivity of 16.8 at 2 bar.Besides,the thermally cross-linked membrane had better anti-aging properties than uncross-linked mixed matrix membrane owing to dense network structure between MWCNTs and NR.