| 摘要 |
Cation-exchange membranes are prepared by treating sheeted thermoplastic polymers containing styrene in polymeric form with a cation-exchange group donor reagent and 0.01-5% of formaldehyde. The polymer may be, e.g. 10-35%, polymeric styrene and a carrier of polyethylene or polypropylene. The membranes may be manufactured by causing the carrier polymer in comminuted form to imbibe a quantity of styrene until the styrene is fully absorbed, heating the mixture to polymerize the styrene, e.g. using benzoyl peroxide as catalyst, forming the polymer into a sheet and treating the sheet with a sulphonating agent, e.g. chlorosulphonic acid, sulphuryl chloride or ether complexes of sulphur trioxide or a complex of sulphur trioxide and 1:4 dioxane, and the formaldehyde. The membrane may then be immersed in sodium hydroxide solution to hydrolyse e.g. the sulphonyl chloride groups and to convert the membrane to its sodium form.
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