Design, Synthesis, Characterization, and Polymerization of Fused-Ring Naphthoxazine Resins

Fused-ring naphthoxazine monomers are synthesized from 1-naphthols and cycloimines derived from piperidine and pyrrolidine. Their polymerization has been confirmed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) as well as by solution and solid-state 1 H and 13 C nuclear magnetic resonance spectroscopy (NMR). A polymerization reaction similar to the traditional benzoxazine monomers is found with oxazine ring disappearing and hydroxyl group forming by the nonisothermal FT-IR experiment. Fused-ring monomers, studied in this work, polymerize at significantly lower temperatures compared to the ordinary benzoxazine resins.