Anomalous copolymerization behavior of styrene and ethyl methacrylate at high conversion

Styrene and ethylmethacrylate were copolymerized in bulk at 62°C and several monomer feed ratios. At moderately high conversion, anomalous copolymerization behaviour occurred. Although the onset of the departures from expected copolymerization behaviour seems to be related to the onset of the gel-effect, this relation did not hold when mimicking higher conversion by adding an amount of homopolymer. Obviously the propagation reactions are not only affected by changes in diffusion characteristics but also by changes in other medium characteristics e.g. interactions between monomeric and copolymeric species. This investigation was supported by The Netherlands Foundation for Chemical Research (SON) with financial aid from The Netherlands Organization for advancement of Pure Research (ZWO).