Complexing effect of N-hydroxyphthalimides in the stereospecific polymerization of methyl methacrylate

A study was carried out on the effect of both the temperature of the reaction medium and structure of the initiator (N-hydroxyphthalimides) on the tacticity of the polymethyl methacrylate obtained under radical polymerization conditions. An increase in the amount of hydroxyl groups in the N-hydroxyphthalimide (NHPI) molecule leads to an increase in syndiotactic sequences in the macromolecule. The Fordham equation was used to calculate the differences in the activation enthalpies and entropies for addition in the iso and syndio positions in the presence of various N-hydroxyphthalimides. In all cases, formation of a syndiotactic polymer is favored.