Generalized two-dimensional infrared correlation spectroscopy (2D-IR) has been applied to the study of the curing reaction process of MDA-benzoxazine.The reaction has been monitored by in situ infrared heating accessory (in situ FTIR).In the in situ FTIR test

appropriate MDA-benzoxazine resin was coated uniformly in the bromine potassium piece and placed in a heating accessory.The heating rate was 2.06 K/min and up to 190 ℃

then hold the same curing temperature in 120 min.The FTIR spectra were processed by omnic and 2D-IR software of Thermo Fisher Company.Two products could be observed after thermal ring opening reaction:the intermediate with C=N bond does not continue the chain-extending reaction

and part of the them exhibits cracking reaction at high temperatures

then schiff alkali with C=N+ bond could be observed.The intermediates with carbonium ions were further cross-linking polymerized

and the polymers were comprised of hydroxyl

trisubstituted aromatic ether and mannich bridge structure.The orders of the key groups in the curing were given by 2D-IR

and the specific chemical structure of the polymer was comprised of trisubstituted aromatic ether and mannich bridge structure.