Peter Hallpap

Solvent influence on cationic copolymerization — part I. Derivation of a rule

Abstract The influence of solvent on cationic copolymerization is investigated by theoretical methods. Mathematical expressions of the quotients of reactivity ratios, r 2 r 1 , of a copolymerization system are derived for the gas phase and solution. Considering some knowledge about solvation energies of charged and uncharged species in various solvents, a rule is derived describing the changes of r1 and r2: the value of r 2 r 1 decreases on moving the copolymerization system to a more polar solvent.

Solvent influence on cationic copolymerization — Part II. Model calculations of the solvent influence on the cationic copolymerization of ethene and isobutene

Abstract The influence of solvent on cationic copolymerization, modelled by ethene/isobutene copolymerization, is investigated by theoretical methods. Solvent influence was simulated by a continuum model after gas phase calculations at the MINDO/3 level. Characteristic changes, caused by the transition from the gas phase to solution (solvent: CH 2 Cl 2 ) were obtained, e.g. an increase of activation barriers and decrease of energy gains of the competing propagation reactions. The quotient of reactivity ratios r 2 / r 1 (1—ethene; 2—isobutene) decreases on changing the copolymerization system to a more polar solvent.