GB815331A - Improvements in and relating to polyacrylonitrile solutions - Google Patents

Abstract

Acrylonitrile, either alone or in admixture with up to 20 per cent of one or more other ethylenically unsaturated compounds such as methyl acrylate, styrene or vinyl acetate, is polymerized in an alkaline concentrated aqueous solution of an inorganic thiocyanate, e.g. sodium thiocyanate, in the presence of a hydroperoxide catalyst, e.g. cumene, tetrahydronaphthalene or tertiary butyl hydroperoxide. The aqueous solution, whch may contain an alcohol, may be rendered alkaline by means of an alkali such as sodium carbonate but, more preferably, by an amine such as tetraethylene pentamine or tetramethyl methylene diamine which also functions as an activator of the hydroperoxide catalyst but which may result in a discoloured solution, an effect which may be avoided by the addition of formaldehyde prior to polymerization. During the course of polymerization further quantities of monomer and catalyst may be added to the reaction system. The resulting polymer solutions may be spun into fibres by the methods described in Specifications 672,775, 714,530, 729,472 or 732,135. Specifications 626,155 and 796,294 also are referred to.