Dimethyl(I-ethoxycarbonyl)vinyl phosphate (DMEVP), prepared in nearly quantitative yield from the reaction of ethyl bromopyruvate with trimethyl phosphite, polymerizes easily by free radical initiated polymerization and copolymerizes readily with styrene (S). Reactivity ratios determined at 60 and 135 degreesC were r(S) = 0.21 +/- 0.02, r(DMEVP) = 0.35 +/- 0.05 and r(S) = 0.31 +/- 0.03, r(DMEVP) = 0.31 +/- 0.04, respectively. Glass transition temperatures and thermal stabilities of the copolymers decreased but char yields obtained upon thermolysis increased as the DMEVP contents of the copolymers increased. H-1, C-13 and P-31 NMR spectra of the copolymers are reported. DMEVP exhibited mild chain transfer activity (C-tr similar to 0.01) in styrene polymerizations conducted at 135 degreesC and in emulsion polymerizations at 50 degreesC. (C) 2003 Elsevier Science Ltd. All rights reserved.