Cocatalysis in Cationic Polymerization

Problems concerned with the principles of cocatalysis and coinitiation as a part of cationic polymerization are discussed. When the established concept of different reactive particles, i.e., contact and separated ion-pairs or free ions, is applied to cationic initiation and propagation centers, then common features for one general process can be drawn even in so diverse cases as “pseudocationic” polymerization, solvent “cocatalysis,” polymerization during condensation and induced by co-monomer addition. A special case of activation by solvent is “cocatalysis” by water.

The model for these cases was found during the interpretation of waves observed on styrene polymerization curves. The formation of ion-pairs proceeds spontaneously. The activation and deactivation of these ion-pairs is effected via coordination of suitable molecules with the former, i.e., by equilibrium shifts