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Copolymerizations by Ionic Mechanism

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  p228-231

2026-01-22

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Copolymerizations by Ionic Mechanism

Ionic copolymerizations are more complicated than free-radical ones. Various complicating factors arise from effects of the counterions and from influences of the solvents. These affect the reactivity ratios. In addition, monomer reactivity is affected by the substituents. They influence the electron densities of the double bonds and in cationic polymerizations the resonance stabilization of the resultant carbon cations. Also, the effects of the counter-ions, the solvents, and even the reaction temperatures can even be greater than that of the substituents in cationic polymerizations. There are only a few studies reported in the literature, where the reactivity ratios were determined for different monomers, using the same temperature, solvent, and counterion. One such study was carried out on cationic copolymerizations of styrene with two substituted styrenes. These were a-methylstyrene, and with chlorostyrene [370–372]. The relative reactivity ratios of these substituted styrenes were correlated with Hammett p