Synthesis and properties of fully bio-based bifunctional polybenzoxazine derived from difuran diamine

Biobased diamine, difuran diamine (B-DFDA) synthesized from benzaldehyde and furfurylamine, was innovatively used to synthesize novel bio-based benzoxazine (V-bfa and Gu-bfa) by reacting with vanillin and guaiacol, respectively. The curing behavior was studied by differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FT-IR), revealing that V-bfa has a low curing temperature, and the aldehyde group was not only consumed but also engaged in the formation of hydrogen bonds. Meanwhile, the V-bfa monomer required lower activation energy (Ek = 119.2 kJ/mol and Eo = 120.9 kJ/mol), suggesting that the aldehyde group has a more unique effect, which may promote the ring opening of oxazine rings. Compared with poly(Gu-bfa), poly(V-bfa) has better mechanical properties, higher glass transition temperature (248 °C) and char yield (59.8%). At the same time, its lower dielectric constant (k) makes it promising for application in the field of electronic packaging and communications.