The mechanism and kinetics of curing of epoxy resin with poly(in-phenylene methylphosphonate) (PMP) was studied by extraction and swelling experiments, DSC, P-31 NMR, and FTIR. It was shown that at linear heating of 20 degrees C/min PMP cures bisphenol A type epoxy resin at 230-300 degrees C, whereas in the presence of catalytic amount of 2-methyl imidazole the curing occurs at 200-230 degrees C. Under isothermal conditions, epoxy resin was cured with PMP after 40-70 min at 150 degrees C. An unusual mechanism of curing due to opening and insertion of epoxy into the phosphonate bond was suggested. (c) 2006 Wiley Periodicals, Inc.