| 摘要 |
A cation-permeable membrane is prepared from 55 parts by weight resorcinol, 47 parts phenol, 103 parts sulphuric acid, 131 parts formaldehyde (37 per cent in water) and 33 parts water. The resorcinol and phenol are melted together at 100 DEG C., cooled to 60 DEG C. and the acid added, cooling to 50 DEG C. allowed and the water added. The mixture is then added to the formaldehyde which was previously cooled to -10 DEG C. The resulting liquid is cast in a thin film and cured for 3 hours at 80-85 DEG C. An anion-permeable membrane is prepared from 108 parts by volume 2-vinyl pyridine (containing 0.1 per cent hydroquinone), 120 parts isopropanol, 108 parts dimethyl sulphate and 81 parts divinyl benzene (76 mol. per cent in ethyl vinyl benzene). The 2-vinyl pyridine is dissolved in the isopropanol and warmed to 55 DEG C., the dimethyl sulphate being added, the mixture cooled and the divinyl benzene added. The resulting liquid is cast in a film and heated to 80 DEG C. for three hours. Specification 720,002 is referred to. |
