Variation of the propagation rate coefficient with pressure and temperature in the free‐radical bulk polymerization of styrene

The propagation rate coefficient K p of the free‐radical bulk polymerization of styrene is determined between 30 and 90°C up to a maximum pressure of 2800 bar. The data from pulsedlaser polymerizations and product analyses by gel‐permeation chromatography (PLP‐GPC) are adequately represented by the expression:\documentclass{article}\pagestyle{empty}\begin{document}$ \ln \left[ {{{k_p } \mathord{\left/ {\vphantom {{k_p } {\left( {{\rm L} \cdot {\rm mol}^{ - {\rm 1}} \cdot {\rm s}^{ - {\rm 1}} } \right)}}} \right. \kern-\nulldelimiterspace} {\left( {{\rm L} \cdot {\rm mol}^{ - {\rm 1}} \cdot {\rm s}^{ - {\rm 1}} } \right)}}} \right] = 17,14 - 1,873 \cdot 10^{ - 4} {p \mathord{\left/ {\vphantom {p {{\rm bar}}}} \right. \kern-\nulldelimiterspace} {{\rm bar}}} - \frac{{3748}}{{{T \mathord{\left/ {\vphantom {T {\rm K}}} \right. \kern-\nulldelimiterspace} {\rm K}}}} + \frac{{0,202}}{{{T \mathord{\left/ {\vphantom {T {\rm K}}} \right. \kern-\nulldelimiterspace} {\rm K}}}}{p \mathord{\left/ {\vphantom {p {{\rm bar}}}} \right. \kern-\nulldelimiterspace} {{\rm bar}}} $\end{document} The conseaquences of deducing activation volumes and activation energies from k p /(L · mol −1 · s −1 ) or from k * p /(kg · mol ‐1 ·. S −1 ) are outlined.