申请人:E. I. DuPont de Nemours and Company
公开号:US04267364A1
公开(公告)日:1981-05-12
Fluorinated ion exchange polymers which have pendant side chains which contain --OCF.sub.2 COOR groups, or which have both pendant side chains containing carboxylic groups and pendant side chains which contain sulfonyl groups, when used in the form of membranes to separate the anode and cathode compartments of an electrolysis cell, permit operation at high current efficiency. Those containing both carboxylic and sulfonyl groups can be made by oxidation of fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups. The fluorinated polymers which have pendant side chains containing sulfinic groups, or both sulfinic and sulfonyl groups, are in turn made from fluorinated polymers which have pendant side chains containing sulfonyl halide groups by reduction with, for example, hydrazine. Those polymers which have only pendant side chains which contain --OCF.sub.2 COOR groups can be made by copolymerization of a mixture of monomers, one of which is a vinyl monomer which contains the indicated carboxylic group. Fluorinated ion exchange polymers which have pendant side chains containing --OCF.sub.2 COOR groups and also pendant side chains which contain sulfonyl groups can also be made by copolymerization of a mixture of monomers, one of which is a vinyl monomer which contains the indicated carboxylic group; and also by treatment of a polymer which contains --OCF.sub.2 CF.sub.2 SO.sub.3 H or salts thereof with a combination of fluorine and oxygen.
含有侧链的氟化离子交换聚合物,其中侧链含有--OCF.sub.2 COOR基团,或同时含有含羧基和含磺酸基的侧链,当以膜的形式用于分离电解池的阳极和阴极间隔室时,能够实现高电流效率。同时含有羧基和磺酸基的聚合物可以通过氧化含有亚磺酸基团或亚磺酸基团和磺酰基团的氟化聚合物制备而成。含有亚磺酸基团或亚磺酸基团和磺酰基团的氟化聚合物是通过还原含有磺酰卤基团的氟化聚合物,例如用肼还原而制备的。只含有侧链的聚合物,其中侧链仅含有--OCF.sub.2 COOR基团,可以通过共聚合一种含有所述羧基的乙烯单体的单体混合物制备。同时含有侧链的氟化离子交换聚合物,其中侧链含有--OCF.sub.2 COOR基团和含有磺酸基的侧链,也可以通过共聚合一种含有所述羧基的乙烯单体的单体混合物制备;以及通过用氟和氧的组合处理含有--OCF.sub.2 CF.sub.2 SO.sub.3 H或其盐的聚合物制备而成。