Bisphenol‐A‐based benzoxazine was copolymerized with epoxy and chain‐extended epoxies in order to study the effect of molecular weight on cured resin properties. Cure behaviour of the copolymers was studied using differential scanning calorimetry, which indicated a single exothermic curing peak at 248 °C. Dynamic mechanical thermal analysis was used to study the viscoelastic properties of the cured resins. A decrease in tan δ peak position and an increase in storage modulus and tan δ peak height were observed due to chain extension. Higher char yield was observed for the copolymer chain extended with tetrabromobisphenol‐A. Copyright © 2005 Society of Chemical Industry

N-(4-hydroxyphenyl)maleimide was melt-blended with the glycidyl ether of bisphenol-A and various mole percentages of 4, 4 -(diaminodiphenylsulfone) bismaleimide. The cure behaviour of the resins was evaluated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The blends showed distinct reductions in the onset of cure (T o ) and peak exothermic (T exo ) temperatures. The blends cured at low temperatures exhibited glass transition temperatures (T g s) higher than the cure temperatures. The cured blends showed high moduli, glass transition temperatures in excess of 250 • C and good thermal stabilities up to 400 • C.