| 초록 |
Sulfonated PVA membranes cross-linked with dimethyl 5-sulfoisophthalate sodium salt (DMSIP Na salt) as a cross-linking agent to introduce sulfonic groups and 4-(2-hydroxyethyl)piperazine-1-propanesulfonic acid (EPPS) containing a sulfonic acid group as a chain extender, were prepared with various compositions. The addition of NaOH in casting processes enhanced the crystallinity of prepared membranes but the degree of cross-linking decreased. The use of pressure in annealing processes caused further cross-linking reaction and crystallization. The increase in the first decomposition temperature, which corresponds to the degradation of PVA side chains via dehydration, was mainly caused by the increase in crystallinity, while further cross-linking mainly leaded to slower and limited first decomposition in this system. The proton conductivity of the membranes at room temperature increased with the amount of DMSIP Na salt and EPPS, and the values were in the range of 10-3 to 10-2 S cm-1. |
