On the copolymerization of acrylonitrile with styrene in the presence of Lewis acid, 1. Effect of zinc chloride concentration

Abstract

AbstractThe copolymerization of acrylonitrile (AN) with styrene (St) is studied in the presence of Lewis acid (LA) (zinc chloride and zinc nitrate) in homogeneous reaction system. It is revealed that the rate of copolymerization (Rp) only slightly increases with the concentration of Lewis acid in the range of ratios [LA]/[AN]≦0,01 at constant concentrations of comonomers and source of radicals, i. e. 2,2′‐azoisobutyronitrile (AIBN). An increase in Rp appears when the ratio [LA]/[AN]≧0,05 is reached. The dependence of log Rp on log [AIBN] is not linear in the systems containing Lewis acid, but is a function of both the total concentration of Lewis acid and AIBN in the reaction system. For the system St‐AN‐Zn(NO3)2 the dependence of the reciprocal value of molecular weight of copolymer on the rate of copolymerization is linear and does not exhibit the minimum found for the system St‐AN‐ZnCl2. The results of kinetic investigations are interpreted from the view‐point of the present ideas on the mechanism of copolymerization in the presence of Lewis acid.