COMPOSITE DIAPHRAGMS

摘要

There are disclosed porous and electrolyte permeable composite diaphragms for electrolysis cells comprising a chemically inert, fibrous porous matrix or substrate impregnated with a copolymer of divinylbenzene and at least one member of the group consisting of 2-vinylpyridine and 4-vinylpyridine. A method of electrolysis of an electrolyte using the said diaphragms and an electrolysis cell containing said diaphragms are also disclosed. The ratio of divinylbenzene to vinylpyridine is 1/16 to 1/1. The preferred substrate is asbestos paper or asbestos mat. The composite diaphragm preferably contains 5 to 25% (by final weight) of said copolymer. Preferably, the copolymer is directly formed on the substrate in the absence of a solvent. The composite diaphragm may also be prepared by impregnating the inert fibrous matrix with a solution of the divinylbenzene and the vinylpyridine in an organic solvent. The solution can contain a polymerization initiator. The organic solvent is evaporated and the dried impregnated matrix is heated in an inert atmosphere to effect polymerization. The composite diaphragm is then washed with an organic solvent to remove unreacted monomers. The composite diaphragms of this invention are dimensionally stable and have good resistance to mechanical abrasion. Their dimensional stability allows for thinner diaphragms with smaller interelectrodic distances with a saving in electrical energy.