基于环糊精分子构筑主客体络合物型阴离子导电膜

Preparation of a full interpenetrating network anion conductive membrane using cyclodextrin host-guest complex

摘要:

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〕）将前述铸膜液中的三种物质交联，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导电膜（CDX-QCSY-PVAY）OH-。结果表明，随着β-环糊精质量分数增加，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-环糊精质量分数为20%时，导电膜综合性能最佳。此时含水率为91.3%，溶胀度为83.4%，拉伸强度为69.5 MPa，断裂伸长率为48.5%，离子交换量为2.64 mmol/g，电导率为7.1×10-2 S/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。

Abstract:

Introduced β-cyclodextrin (β-CD) into a mixed casting solution using polyvinyl alcohol (PVA) and quaternized chitosan (QCS) as a film matrix, and then crosslinked three substances in the aforementioned casting solution through a combined crosslinking agent (glutaraldehyde (GA) and melamine (MA)), a series of host-guest complex (CDX-QCSY-PVAY) OH- conductive membranes based on cyclodextrin molecule with full interpenetrating network structure were prepared. The results showed that with the growth of β-cyclodextrin content, the content of —OH increased, and the amount of OH- adsorption by complexing Ca2+ increasesed, cause to the ion exchange capacity(IEC) and conductivity and tensile strength and so on increased, but water uptake, swelling ratio and elongation at break decreased. When the content of β-cyclodextrin was 20%, the comprehensive performance was the best. The water uptake and swelling ratio were 91.3% and 83.4%, separately, the tensile strength and elongation at break were 69.5% and 48.5%. And the ion exchange capacity was 2.64 mmol/g, conductivity can reached 7.1 × 10-2 S/cm at 70 ℃. The conductivity of the above film samples can reached 83% of the original conductivity after soaking for 240 h in an alkaline environment of 6 mol/L KOH solution at 70 ℃, and still maintained good alkali stability.