Stereospecific Radical Polymerization of #alpha#-(Alkoxymethyl)acrylates Controlled by a Catalytic Amount of Zinc Halides

摘要

The stereospecific radical polymerization of #alpha#-(alkoxymethyl)acrylates-benzyl #alpha#-(methoxymethyl)acrylate, benzyl #alpha#-(ethoxymethyl)acrylate, and ethyl #alpha#-(ethoxymethyl)acrylate-in hte presence of a catalytic amount of zinc halides (ZnCl_2 and ZnBr_2) was attained, and the obtained polymers had very different tacticities, rich in syndiotacticity (up to r = 0.71), from that prepared in the absence of a zinc salt (atactic). In contrast, no change was observed in the stereoregularity of the polymethacrylates radically obtained in the presence of ZnBr_2 as an additive. The coordination of zinc salts to polar #alpha#-substituents on the #omega#-end of the propagating polymer and the monomer must play an important part in this system.