High temperature copolymerization of styrene/ethyl acrylate: Reactivity ratio estimation in bulk and solution

Abstract

Styrene/ethyl acrylate (Sty/EA) free-radical copolymerizations have been conducted in bulk with and without initiator and in solution using p-xylene and m-xylene (30 wt% and 60 wt% solvent level) at 100• C and 130• C. The monomer reactivity ratio values and their temperature dependence have been determined from low conversion copolymer composition data using the computer software package RREVM, which is based on the error in variables model (EVM) method. Copolymer composition data at low conversion confirmed the MayoLewis model at both temperatures. The reactivity ratio values of the Sty/EA system do not seem to change with dilution by nonpolar solvents at low concentration from the reactivity ratio values obtained in bulk with and without initiator. However, xylene isomers were found to have a slight effect on the reactivity ratio value of ethyl acrylate when high solvent concentration was utilized.

Using 1H‐NMR spectroscopy for the kinetic study of the in situ solution free‐radical copolymerization of styrene and ethyl acrylate

“…r St and r EA increase with increasing reaction temperature, as shown in Table I. Sahloul and Penlidis17 investigated the dependence of r St and r EA on the temperature. They observed r St and r EA increasing with increasing temperature.…”

“…The determination of the reactivity ratio has been the major focus of studies described in the open literature for this copolymerization system. [7][8][9][10][11][12][13][14][15][16][17] The results of numerous studies in which the reactivity ratios have been calculated are summarized in Table I. The reactivity ratios for EA (r EA ) and St (r St ) are in the range of about 0.13-0.23 and 0.69-1.36, respectively.…”

“…The determination of the reactivity ratio has been the major focus of studies described in the open literature for this copolymerization system 7–17. The results of numerous studies in which the reactivity ratios have been calculated are summarized in Table I.…”

Practical Prediction of Heteropolymer Composition and Drift

“…It is important to note, however, that reactivity ratios are affected by solvent and reaction temperature. , For CRP of polymers with small DP at low conversions, the assumptions of the Mayo–Lewis model are invalidated due to deviating reactivities of short chain radicals, kinetics of the initiation step, and the activation/deactivation equilibria. Thus, the apparent reactivity ratios, as measured for low DP polymers in CRP, may differ from those of free radical polymerizations .…”