A semiempirical quantum mechanical study of cationically catalyzed homopolymerization and copolymerization of vinyl ethers and epoxides

The purpose of this study was to use the semiempirical quantum mechanical computational method, AM1, to investigate vinyl ether cationic homopolymerization, epoxide homopolymerization, and copolymerization of selected vinyl ethers with a model epoxide (cyclohexene oxide). Homopolymerization studies of 19 vinyl ethers showed that activation enthalpies ranged between 0.0 and 15 kcal/mol, and that the enthalpies of reaction for homopolymerization were nearly all exothermic. Homopolymerization of three epoxides predicted low activation enthalpies, some of which were virtually activationless. All ring-opening epoxide polymerizations were exothermic. Copolymerization of three vinyl ethers with cyclohexene oxide gave activation enthalpies that varied between 2.7 and 4.0 kcal/mol, and the enthalpies of reaction for copolymerization were all exothermic.