Remarkable Solvent Effects of Oxygen- and Sulfur-Containing Compounds on the Propagation Rate of Methyl Methacrylate

Abstract

Abstract The propagation kinetics of methyl methacrylate (MMA) in the presence of a number of oxygen- and sulfur-containing compounds have been investigated. Solvents used were 2-methyl-1,3-dioxepane (MDOP), 2,6-dithiaheptane (DTHP) and 1,5-dithiacyclooctane (DTCO). In the presence of DTHP and DTCO, the propagation rate coefficient, k p, of MMA was found to be 25% to 100% higher compared to bulk polymerisations under the same conditions. The significant increase of k p was explained by electron donation from the sulfur-containing solvents, which increased the reactivity of the macroradicals. MDOP had no observable effect on k p. The solvent influence on polymer tacticity was also studied using both 1H and 13C NMR spectroscopy. No significant influence of the solvent on polymer tacticity was found.