High mol. wt. fluorinated copolymer contg. ion-exchanger gps. - prepd. by copolymerising a fluorinated ethylenically unsatd. monomer and a functional monomer

摘要

Fluorinated copolymers contg. ion-exchanger gps. and 1-50 mol. % component contg. COOH gps., or gps. convertible to COOH gps., are prepd. by copolymerising a fluorinated ethylenically unsatd. monomer (II), and a functional monomer (I), contg. the functional gps., in the presence of polymerisation starter source. The copolymerisation takes place in 0-10 (5) mols. inert organic solvent/mol. (I), under pressure >6 (6-50) kg./cm2, and a copolymer is obtd. having high mol. wt., as expressed by TQ-value (melt flow index) >150 (170-340) esp. 180-300 degrees C, and ion exchanger capacity 0.5-4(0.8-3) esp. 1-2.2 m. equiv./g. of dry polymer. The copolymer is esp. a COOH-type cation exchanger, active as ion exchanger membrane in electrolysis of an aq. soln. of electrolyte, e.g., prepn. of NaOH by NaCl electrolysis. The copolymer can be prepd. with high copolymerisation reaction velocity. The diaphragms are suitable for prepg. a pure alkali hydroxide, in high concn. wid with a high current efficiency.