0000000000205383
AUTHOR
Hai Dong
Kinetic Analysis of “Living” Polymerization Processes Exhibiting Slow Equilibria. 5. Effect of Monomer Transfer in Cationic Polymerization and Similar Living Processes
This work deals with the kinetics of polymerization processes with chain transfer to monomer and reversible formation of dormant species. Such a mechanism is typical for cationic polymerization in the presence of Lewis acids as co-initiators. The expressions of number- and weight-average degrees of polymerization and polydispersity index are derived rigorously for a mechanism with free ions as the active species, but it is also applied to other mechanisms, e.g., ion pairs as active species. Plots of polydispersity index versus monomer conversion can be easily computed on a PC computer even though the expressions for the weight-average degree of polymerization and the concentration of residu…
Kinetic analysis of "living" polymerization processes exhibiting slow equilibria. 6. Cationic polymerization involving covalent species, ion pairs, and free cations
The kinetics of cationic polymerization is studied theoretically in accordance with a three-state mechanism which consists of two successive equilibria: the ionization/ion collapse equilibrium between covalent species and ion pairs, and the subsequent dissociation/association equilibrium between ion pairs and free ions. The number- and weight-average degrees of polymerization and the polydispersity index (PDI), Pw/Pn, are derived. The molecular weight distribution of the polymer generated from this mechanism is generally broader than that of polymers formed via a two-state mechanism, i.e. with only one equilibrium either between covalent species and ion pairs or between covalent species an…