Mechanism of the copolymerization of styrene with methyl,ethyl, and n-butyl acrylates in the presence of zinc chloride

The complexes of methyl acrylate (MA), ethyl acrylate (EA) and n-butyl acrylate (BA) with zinc chloride (ZnCl₂) were prepared at 300 K and found to be polar in nature. The viscosity and density of the complexes increased while the tendency to form a binary complex decreased with increase in size of the alkyl substituents of the acrylate monomers. The copolymerization of MA and BA with styrene (Sty) followed a cross-propagation mechanism, whereas the copolymerization of EA with Sty followed a radical-complex mechanism in the presence of their complexes with ZnCl₂.