Update and critical reanalysis of IUPAC benchmark propagation rate coefficient data

Abstract

We present an updated and expanded dataset of benchmark propagation rate coefficient (k_p) data obtained from pulsed laser polymerization (PLP) of 13 vinyl monomers (styrene, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, cyclohexyl methacrylate, glycidyl methacrylate, benzyl methacrylate, isobornyl methacrylate, butyl acrylate, methacrylic acid (15% aq. solution), methyl acrylate and vinyl acetate. The data are reanalyzed using a statistical model that takes into account systematic interlaboratory variation, leading to significantly larger joint confidence regions and slightly adjusted figures relative to the original IUPAC benchmark publications. A full set of revised IUPAC benchmark values of pre-exponential factors, activation energies (EA) and k_p at 25 °C are presented. 81 independent PLP studies were pooled to give estimates of the standard interlaboratory error in measurements of ln(k_p at 25 °C) and E_A, which were obtained as 0.08 and 1.4 kJ mol⁻¹, respectively, with a correlation coefficient of 0.04. We recommend that these values be used to estimate the uncertainty in PLP studies that have not been independently replicated.