A semiempirical quantum mechanical study of the cationic homopolymerization of expanding and potentially expanding monomer systems

The cationic homopolymerization reactions of expanding and potentially expanding monomer systems were modeled and the energies of activation were calculated using the AM1 semiempirical quantum mechanical method. The results were used to determine the relative reactivity of study monomers with respect to spiro-orthocarbonates (SOC) and epoxides. All expanding monomers studied were endothermic by 4–16kcal/mol except the methylated bicyclic orthoesters which had an enthalpy of reaction of essentially 0kcal/mol. Three potentially expanding monomers were exothermic by 3–18kcal/mol. The energies of activation for all expanding monomers ranged from 28–37kcal/mol. The energies of activation for SOCs and epoxides are approximately 32 and 0–3kcal/mol, respectively [1], [2]