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 c omputational method, AM1, to investigate vinyl ether cationic homopolymeriz ation, epoxide homopolymerization, and copolymerization of selected vinyl e thers 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 we re nearly all exothermic, Homopolymerization of three epoxides predicted lo w activation enthalpies, some of which were virtually activationless. All r ing opening epoxide polymerizations were exothermic, Copolymerization of th ree vinyl ethers with cyclohexene oxide gave activation enthalpies that var ied between 2.7 and 4.0 kcal/mol, and the enthalpies of reaction for copoly merization were all exothermic. (C) 2000 Elsevier Science B.V. All rights r eserved.