Estimation of Reactivity Ratios in the Copolymerization of Styrene and VeoVa‐10

The styrene and vinyl neodecanoate copolymerization system shows a strong tendency to form two separate homopolymers. In order to improve the feeding strategies and hence the copolymer uniformity, it is necessary to know the reactivity ratios between these monomers. The error‐in‐variables‐method (EVM) is the most recommended mathematical procedure for estimating these parameters. Experiments on free‐radical copolymerization in solution in sealed ampoules are carried out to provide data for the conversion (via gravimetry) and fractional monomer compositions (via Fourier transform mid‐infrared (mid‐FT‐IR) spectroscopy). These data allow estimation of the reactivity ratios. EVM appropriately takes into account the experimental errors in the data and allows determination of the reactivity ratio values by the Mayo–Lewis model (r₁ = 28.60 and r₂ = 1.23). The convergence and robustness of the method decrease considerably with a larger discrepancy between the reactivity values.