Critically evaluated rate coefficients for free‐radical polymerization, 1. Propagation rate coefficient for styrene

Pulsed‐laser polymerization (PLP) in conjugation with molecular weight distribution (MWD) measurement has emerged as the method of choice for determining the propagation rate coefficient kp in free‐radical polymerizations. Detailed guidelines for using this technique (including essential internal consistency checks) and reporting the results therefrom are given by the authors, members of the IUPAC Working Party on Modeling of kinetics and processes of polymerization. The results for PLP‐MWD kp measurements from many laboratories for bulk free‐radical polymerization of styrene at low conversions and ambient pressure are collated, and are in excellent agreement. They are therefore recommended as constituting a benchmark data set, one that is best fitted by (Formula Presented.) (the confidence ellipsoid for the Arrhenius parameters is also given). These benchmark data are also used to evaluate the merits of several other methods for determining kp; it is found that appropriately calibrated electron paramagnetic resonance spectroscopy appears to yield reliable values of kp for styrene. © 1995 Hüthig & Wepf Verlag, Zug