Synthesis of bio-diamine derived main-chain type benzoxazine resins with low surface free energy

A series of bio-based fluorin-free main-chain type benzoxazine precursors were synthesized via bisphenol A/bisphenol F/diallyl bisphenol A, Priamine 1074 and paraformaldehyde by Mannich condensation reaction. Chemical structures of these obtained main-chain type precursors were characterized by FT-IR and NMR spectroscopies. The polymerization processes were studied by differential scanning calorimeter (DSC) and in situ FT-IR analysis. Besides, the contact angle and surface free energy of polybenzoxazine coatings were measured by water contact angle instrument. Moreover, the thermal performance of the resulting polybenzoxazine thermosets were evaluated by dynamic mechanical analyzer (DMA) and thermogravimetric analysis (TGA). Through the above various measurements, the newly developed bio-based main-chain type polybenzoxazine resins show good thermal stability and low surface free energy, suggesting great potential for applications as high-performance resin matrix.