聚胍盐离子液体的合成及其在阴离子交换膜中的应用

Synthesis of guanidinium polymeric ionic liquid and its application in anion exchange membrane

以溴丙烯、N,N,N′,N′-四甲基胍(TMG)为原料,合成N,N,N′,N′-四甲基-N″-丙烯基胍离子液体(IL),以偶氮二异丁氰(AIBN)为引发剂,将丙烯基胍离子液体聚合成聚胍盐离子液体(PIL).通过核磁共振氢谱(1 H NMR)对离子液体及聚离子液体进行分析,并将二者引入聚砜为基质的阴离子交换膜中,采用流延法制备了聚砜/离子液体复合膜(PSf-IL)和聚砜/聚离子液体复合膜(PSf-PIL).借助红外(FTIR)、扫描电镜(SEM)、热重分析(TGA)和机械性能测试等对两种复合膜的结构及理化性能进行测试.结果表明,当离子液体与聚离子液体添加量相同时,聚砜/聚离子液体复合膜的各项性能均好于聚砜/离子液体复合膜.当质量比PSf∶PIL=1∶0.2时,PSf-PIL复合膜离子交换量为0.68meq/g;80℃时电导率为7.8×10-2 S/cm;经过80℃、400h、KOH(6mol/L)的耐碱性测试后,虽然胍盐离子液体部分降解,但K+会进入膜微结构中,使得电导率不降反升,为初始值的1.17倍,膜质量损失小于3%,IEC由原来的0.68meq/g上升到0.79meq/g.

N,N,N′,N′-tetramethyl-N″-propenyl guanidine ionic liquids（ILs）were synthesized from bromopropylene and N,N,N′,N′-tetramethylguanidine（TMG）.Using AIBN as initiator,the ionic liquidof polyacrylic guanidine was polymerized into guanidinium polymeric ionic liquid（PIL）.The structure of PIL and IL was characterized by 1 HNMR.The PSf-IL composite membrane and the PSf-PIL composite membrane were prepared by the flow casting method,and were characterized by means of infrared（FTIR）,electron microscopy（SEM）,thermogravimetric analysis（TGA）.Mechanical properties of the two composite membrane structure and physical and chemical properties were characterized.The results showed that the properties of PSf-PIL composite membranes were better than that of PSf-IL composite membranes when IL and PIL were added in the same amount.When the weight ratio of PSf to PIL was1∶0.2,the IECof PSf-PIL composite membrane was 0.68 meq/g and the conductivity was 7.8×10-2 S/cm at 80 ℃.After the composite membrane has been subjected to the alkali resistance test at 80℃for 400 h and KOH（6 mol/L）,K＋entered the membrane microstructure even though the partial dissociation of the guanidinium ionic liquid,making conductivity was 1.17 times the initial value,weight the original0.974 times;IECincreased to 0.79 meq/g.