Bio-based benzoxazine monomer and polymer based on vanillin and difurfuryl diamine

A type of bio-based benzoxazine monomer based on difurfuryl diamine (DFDA) obtained by the coupling of furfuryl amine using formaldehyde will be discussed. The benzoxazine monomer was synthesized by reacting DFDA with renewable phenolic vanillin and formaldehyde. This benzoxazine system was purified by precipitation to obtain solid powders that melt at 55 °C to form low viscosity liquids that can be readily used to impregnate fiber reinforcements. Onset cure temperature is 163 °C and the autocatalytic reaction behavior was observed. The resulting polybenzoxazine has about 244 °C after post curing. It was found that the polybenzoxazine network containing high content of furan rings in the backbone provides the improvement of 800 °C char yield compared with Bisphenol A (BPA) based polybenzoxaizines greater than 50% measured by TGA temperature ramps in an inert environment. This paper will discuss processing and thermal characteristics of this highly renewable material, which are useful for high temperature applications.