Synthesis and properties of biobased mono-benzoxazine resins from natural renewable pterostilbene

Two novel fully biobased mono-benzoxazine resins have been designed and synthesized using pterostilbene , furfurylamine/stearylamine and paraformaldehyde via a solventless reaction. The structures of newly obtained mono-benzoxazine monomers have been characterized by nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and high-resolution mass spectrometry (HR-MS). The detailed assignments for oxazine-ring protons and carbons in each benzoxazine are identified using 1 H– 13 C heteronuclear multiple quantum coherence spectroscopy (HMQC). Besides, the polymerization processes of benzoxazine resins are studied by differential scanning calorimetry (DSC) and in situ FT-IR spectroscopy, and the thermal stability of their corresponding polybenzoxazines are investigated by thermogravimetric analysis (TGA). Moreover, coatings of both polybenzoxazines on glass slides and low-carbon steels have also been prepared to evaluate their anticorrosion performance. The results indicate that both polybenzoxazines possess good thermal stability and can play efficient roles for shielding corrosion as coatings. Therefore, the current study highlights the utility of the natural renewable pterostilbene as a promising candidate to prepare high-performance bio-based polybenzoxazines.