- Average termination rate coefficients in emulsion polymerization: effect of compartmentalization on free-radical lifetimes. SW Prescott, MJ Ballard and RG Gilbert. Journal of Polymer Science Part A: Polymer Chemistry, 43(5), 1076–1089, 2005.
Abstract:
A method is presented by which the time-dependent average termination
rate coefficient in an emulsion polymerization may be calculated
as an appropriate average of the chain-length-dependent termination
rate coefficients. The method takes advantage of the fact that the
overall termination rate is dominated by terminations between rapidly
moving short radicals and much slower long ones. This termination
rate coefficient is suitable for use in the Smith-Ewart equations
describing the compartmentalization of radicals in an emulsion polymerization.
Rate data in emulsion polymerizations can be quantitatively interpreted
if the kinetics fall into one of two categories: zero-one (showing
compartmentalization; intraparticle termination is not rate-determining)
or pseudo-bulk (no compartmentalization; intraparticle termination
is rate-determining). The new method can be used to interpret rate
data for systems falling between these categories and also can be
used to find termination rate coefficients from Monte Carlo simulations
of termination kinetics. The latter is especially useful for predicting
and understanding kinetics in controlled radical polymerizations
in disperse media.
Last edited: Friday September 10, 2010
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