Radiation-induced polymerization by free ions. Part 3.—Rate constants for cationic polymerization

Abstract

The general kinetics of radiation-induced ionic polymerization are discussed and the effects resulting from impurity termination are analyzed quantitatively. A method is described for the calculation of the propagation rate constants k_p by combining measurements of polymerization rates with conductivity determinations of the ionic lifetime in the stationary state. The rate constant for cationic propagation by free ions is ca. 4 × 10⁶ M^–1 sec^–1 for both styrene and α-methylstyrene in the bulk monomer. This large value suggests that the lower results obtained previously for styrene by the use of chemical cationic catalysts refer mainly to ion pairs of varying reactivity.