Thermal Curing of Benzoxazine Blends from Cardanol- Furfurylamine and Diphenolic Acid-Aniline

Cardanol-furfurylamine benzoxazine (CFB) is a bio-based resin thanks to cardanol as a by-product of cashew nut shell liquid. Polybenzoxanize obtained from CFB exhibited high thermal stability, however, it requires a high thermal curing temperature. This research was aimed to reduce the curing temperature of CFB by blending it and diphenolic acid-aniline benzoxazine (DAB). The blend molar ratio of CFB:DAB was 4:1. Under thermal curing, carboxyl group in DAB was degraded and accelerated ring-opening polymerization of CFB/DAB blend so that no catalyst was used. Different curing temperatures of CFB/DAB blend was investigated. Results from fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) proved that the ring-opening initiated at 115.2 ?C for DAB, 141.6 ?C for blend and 206.2 ?C for CFB. It proved that CfB/DAB blend could start thermal curing at an obvious lower temperature. Moreover, polybenzoxazine synthesized from CFB/DAB blend exhibited good thermal stability compared to DAB-polybenzoxazine and obtained higher char yields compared to CFB-polybenzoxazine.