| 摘要 |
1479388 Cation exchange membranes in electrolytic cells DIAMOND SHAMROCK CORP 15 Oct 1975 [16 Oct 1974 16 June 1975] 42309/75 Heading C7B [Also in Division C3] Cation exchange membranes for use in an electrolytic cell are obtained by surface treatment of a membrane comprising a fluorine containing polymer having pendant sulphonyl groups with an acyclic polyamine other than ethylene diamine to convert the sulphonyl groups to the form -SO 2 NRR' NRR", optionally after a pre-treatment with ethylene diamine, on one side, the remaining sulphonyl groups being in the form -SO 3 R where R is H, Na or K. R' is C 3 -C 6 alkylene, Z 2 NR", or ZNR" Z 2 NR", Z is C 2 -C 6 alkylene and R" is R or -SO 2 -. If the membrane is first treated with ethylene diamine, groups to a depth of 2.5-25 microns are converted to -SO 2 NR-C 2 H 4 -NRR". The remainder of the treated depth, up to about 50 microns and to an extent of at least 10 microns in the absence of ethylene diamine treatment, is treated with a polyamine e.g. 1,3-diaminopropane, dipropylene triamine, diethylene triamine, or butylene diamine. Treatment with alkali metal hydroxide converts other sulphonyl groups to the -SO 3 R form. The polymer is preferably a copolymer of tetrafluoroethylene and CF 2 =CFY f SO 2 F where Yf is a C 2 -C 8 bivalent perflourinated aliphatic radical. The membranes are used in the electrolysis of brine with the treated surface facing the cathode. |
