Phenolic Naphthoxazines as Curing Promoters for Benzoxazines

The effect of phenolic hydroxyl bearing naphthoxazines as catalysts for the ring-opening polymerization (ROP) of simple 1,3-benzoxazines was investigated. The latent catalytic role of napthoxazines in the curing process of the mixtures was demonstrated by DSC and FT-IR investigations. It was found that phenolic naphthoxazines cause clear reduction in ROP temperature, particularly when electron-withdrawing groups are attached and an onset ROP temperature as low as 169 °C is attained. Thermal properties of the final polymers were also analyzed, and no significant effect of naphthoxazines on the thermal stability of the cured polybenzoxazines was observed.