Question

Discuss the general effects of temperature, solvent, and catalyst on the monomer reactivity ratios in ionic copolymerization. how do these compare with the corresponding effects in radical copolymerization?

Answer 1

In ionic copolymerization, the interaction between monomers play the major role in deciding the reactivity ratios for the polymerization. Thus, formation of polymer in non-polar solvents is favored as the radicals do not get solvated and are free to react with one another. As the temperature goes up, the formation of radicals also increases and thus the reactivity ratio also increases. The catalyst used, also favors the formation of separate radicals for the reaction.

On the other hand, in ionic polymerization, formation of ion-pair is what defines the reactivity ratio of polymerization. Thus polar solvents which help forming the ion-pair favors this reaction. Also the ion-pair stays close when lower temperature is used for polymerization and thus favors higher reactivity ratios.