Modification of cation exchange membrane by grafted poly(4-vinyl-N-methylpyridinium-iodide)

✍ Scribed by Kazuhiro Shimasaki; Hirofumi Ihara; Yukio Mizutani

• Book ID: 102735921
• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 714 KB
• Volume: 34
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1987.070340318

✦ Synopsis

It is well known that cation exchange membranes, having a very thin layer of a cationic polyelectrolyte on the membrane surface, have preferential permselectivity for monovalent cations in a monovalent-divalent cations system. We studied the relationship between preferential permselectivity and molecular structure of the cationic polyelectrolyte. Grafted poly(4-vinyl-Nmethylpyridinium-iodide) was used and was compared with poly(4-vinyl-N-methylpyridiniumiodide). The backbone polymers were poly(styrene-co-p-benzylstyrene) and poly@enzyl), onto which 4-vinylpyridine was grafted by anionic polymerization and then quatemized with CH,I. The gr'afted poly(4vinyl-N-methylpyridinium-iodide) is effective in making the cation exchange membrane preferentially permselective for Na+ in a Na+ -Ca2+ system and is more preferable than poly(4-vinyl-N-methylpyridinium-iodide) in terms of electric resistance of the membrane. However, the relationship between the molecular structure of the cationic polyelectrolyte and the durability of the preferential permselectivity is not clear.