Chain polymerization is an important reaction to prepare polymer compounds

and is also an important knowledge in the course of polymer chemistry. In the course of teaching chain polymerization

the selectivity of vinyl monomers on polymerisation types has always been a key and difficult problem in process of polymer chemistry teaching. In this paper

the direction and intensity of the substituent electron effect are discussed qualitatively and quantitatively from three aspects: the induction effect

the conjugation effect and the substituent radical constant

then the reasons for the difference in polymerization types between the two groups of monomers were analyzed by using vinylidene chloride and vinylidene fluoride

methyl acrylate and vinyl acetate as examples

in order to help students understand the selectivity of the vinyl monomers on the type of polymerization.