Synthesis, characterization of new bisphenol-based benzoxazines and the thermal properties of their polymers

New bisphenol-based benzoxazines (BBA-a and BBA-bra) were synthesized from bisphenol containing trityl group, paraformaldehyde, aniline and 2,4,6-tribromoaniline by a solventless method. The chemical structure of the monomers was analyzed by FTIR, 1H NMR and elemental analysis. FTIR and differential scanning calorimetry (DSC) indicated that the polymerization of BBA-a and BBA-bra was thermally initiated and occurred via ring opening of benzoxazine monomers. Comparing with that of BBA-a, the curing exothermic peak of BBA-bra shifted from 230 to 245 °C. Thermogravimetry (TG) showed that PBZ from BBA-a and BBA-bra (named as PBBA-a and PBBA-bra, respectively) had superior thermal stability. The char yields of PBBA-a and PBBA-bra at 800 °C were 42.37 and 48.30%, respectively.