Biobased Bisbenzoxazine Resins Derived from Natural Renewable Monophenols and Diamine: Synthesis and Property Investigations

Synthesizing biobased thermosetting resins with unique performance from renewable resources has attracted increasing attention because of the sustainable development aspirations from human beings. However, diamine-derived bio-bisbenzoxazine resins have rarely been reported because of the lack of naturally sourced diamines in nature. Here, we report a series of biobased bisbenzoxazine resins via green synthetic methods using various monophenols (guaiacol/sesamol/peterostilbene) and a diamine (Priamine 1074) as natural renewable raw materials. Chemical structural details of these bisbenzoxazines were characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy, and size exclusion chromatography. Thermally activated polymerization behaviors were investigated by differential scanning calorimetry thermograms and in situ FT-IR analysis. Besides, surface properties of each resin were studied through the contact angle measurement, and surface-free-energy values without varying too much were achieved from this series of Priamine 1074-derived bioresin coatings before and after different polymerization cycles. Moreover, thermal stability of the fully polymerized bioresins was evaluated by dynamic mechanical analysis and thermogravimetry analyses. These bio-polybenzoxazines all showed good thermal properties with Td10 greater than 350 °C. Consequently, this new family of biobased bisbenzoxazine thermosetting resins and their corresponding polybenzoxazines exhibit outstanding surface and thermal performances, providing great potential applications for high-performance polymeric coating materials.