High‐Performance Bio‐Benzoxazine Resins Derived From Natural Renewable Vanillin: Synthesis, Characterization, and Properties of Their Thermosets

ABSTRACT In this study, we used vanillin and furfurylamine from renewable resources as starting materials and successfully synthesized an innovative derivative of bisbenzoxazine (MH‐fa) using the Mannich reaction. We characterized the chemical structure of the newly synthesized bisbenzoxazine compound using high‐resolution mass spectrometry (HR‐MS) technology. The results of nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy analysis (FT‐IR) confirmed the successful synthesis of the target compound. The synthesis of the benzoxazine copolymer (MH‐fa‐co‐DDM‐BMI) was achieved by leveraging the reversibility of the Diels–Alder reaction between the MH‐fa monomer and 4,4′‐bismaleimide diphenylmethane (DDM‐BMI). In addition, the investigation into the polymerization behavior of benzoxazine monomer and its corresponding main‐chain copolymer was conducted employing differential scanning calorimetry (DSC) along with in situ FT‐IR. We studied the thermal stability and combustion performance of two samples using thermogravimetric analysis (TGA) and microscale combustion calorimetry (MCC). The results revealed that the bio‐based bisbenzoxazine exhibited excellent heat resistance and flame retardancy. Specifically, poly(MH‐fa) exhibits a T d10 value of 350°C and a Y c value of 62.3% at 800°C. Furthermore, the material exhibits an extremely low heat release rate (20.4 J g −1 K −1 ), highlighting its potential applications in the field of high‐efficiency flame retardant materials.