基于环糊精分子构筑主客体络合型OH^-导电膜

Preparation of Host-guest Complex OH^- Conductive Membrane Based on Cyclodextrin Molecules

将β-环糊精(β-CD)引入到以聚乙烯醇(PVA)和季铵化壳聚糖(QCS)为膜基质的混合铸膜液中,然后借助联合交联剂〔戊二醛(GA)+三聚氰胺(MA)〕将前述铸膜液中的3种物质交联,制备一系列环糊精含量不同、具有全互穿网络结构的主客体络合物型OH-导电膜(CDX-QCSY-PVAY,X为β-CD的含量,Y为QCS与PVA的含量)。结果表明,随着β-CD质量分数的增加,羟基含量增加,络合Ca2+吸附OH–数量增加,离子交换量、电导率与拉伸强度等均呈上升趋势,但含水率、溶胀度与断裂伸长率呈下降趋势。当β-CD含量为20%(以β-CD、QCS和PVA的总质量为基准,下同)时,导电膜综合性能最佳。此时含水率为71.1%,溶胀度为63.7%,拉伸强度为69.5 MPa,断裂伸长率为48.5%,离子交换量为2.43 mmol/g,电导率为7.1×10-2S/cm(70℃)。在70℃、6 mol/L KOH溶液中,上述膜样品在泡碱240 h后的电导率降低了17%,具有较好的耐碱稳定性。

β-cyclodextrin(β-CD)was introduced into a mixed casting solution using polyvinyl alcohol(PVA)and quaternized chitosan(QCS)as film matrix,and then these three substances were crosslinked in the presence of a combined crosslinking agent of glutaraldehyde(GA)and melamine(MA)to preparea series of host-guest complex(CDX-QCSY-PVAY,X is the mass fraction ofβ-CD,Y is the mass fraction of QCS and PVA)OH–conductive membranes based on cyclodextrin molecules with full interpenetrating network structure.The results showed that when the mass fraction ofβ-CD increased,the content of hydroxyl group and the amount of OH-adsorption by complexing Ca2+increased,the ion exchange capacity(IEC),the conductivity and the tensile strength all showed an increasing trend.However the water uptake,swelling ratio and elongation at break decreased.When the dosage ofβ-CD was 20%(basd on the total mass ofβ-CD、QCS and PVA,the same below),the conductive membrane exhibited the best comprehensive performance.The water uptake and swelling ratio were 71.1%and 63.7%,respectively.The tensile strength and elongation at break were 69.5%and 48.5%,respectively.And the ion exchange capacity was 2.64 mmol/g,the conductivity reached 7.1×10-2 S/cm at 70℃.The conductivity of the above membrane was only decreased 17%after soaking for 240 h in 6 mol/L KOH solution at 70℃,indicating that the membrane had good alkali stability.