Effects of aromatic diboronic acid on thermal charateristics of polybenzoxazines based on phenol and aniline

[Display omitted] •Polybenzoxazine-aromatic diboronic acid composites were prepared and characterized.•Thermal characteristics of polybenzoxazine were improved upon addition of boronic acid.•Interactions between benzoxazine and boronic acid were detected. In this work, polybenzoxazines based on phenol and aniline were prepared by curing as-synthesized and purified monomers in the presence of aromatic diboronic acid, BDBA. Condensation reactions between BOH groups of diboronic acid and phenolic OH groups of benzoxazine took place during curing only when unreacted phenol, or low mass oligomers were present in the medium. Generation of fragments involving B-O-C groups and significant improvement in thermal characteristics were detected upon curing the as-synthesized monomer in the presence of even 5 wt %BDBA. On the other hand, enhancement in thermal characteristics was not detected for the polybenzoxazine prepared by curing the purified monomer, when the wt % of BDBA was lower than 15%.