Dialkyl vinylphosphonates such as dimethyl vinylphosphonate (DMVP) and diethyl vinylphosphonate were quantitatively polymerized with dicumyl peroxide (DCPO) at 130 degrees C in bulk. The polymerization of DMVP with DCPO was kinetically studied in bulk by fourier transform near-infrared spectroscopy (FTNIR and electron spin resonance (ESR) spectroscopy. The initial polymerization rate (R-p) was given by Rp = k[DCPO](0.5)[DMVP](1.0) at 110 degrees C, being the same as that of the conventional radical polymerization involving bimolecular termination. The overall activation energy of the polymerization was estimated to be 26.2 kcal/mol. The polymerization system involved ESR-observable propagating polymer radicals under the practical polymerization conditions. ESR-determined rate constants of propagation (k(p)) 103 L/mol s at 110 degrees C, respectively. The molecular weight of the resultant poly(DMVP)s was low (M, = 3.4 - 3.5 X 103), because of the high chain transfer constant (C. = 3.9 X 10(-2) at 110 degrees C) to the monomer. DMVP (M-1) showed a considerably high reactivity in the radical copolymerization with trimethoxyvinylsilane (TMVS) (M-2) at 110 degrees C in bulk, giving an inorganic component-containing functional copolymer with potential flame-retardant properties; r(1) = 1.6 and r(2) = 0. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 109: 3746-3752, 2008.