Equol–Thiophene‐Based Benzoxazine: Synthesis, Curing Kinetics, and Blend Properties

A novel biobased bifunctional benzoxazine monomer EQ‐tma was successfully synthesized via Mannich condensation using equol and 2‐thiophenemethylamine as starting materials. The chemical structure of the monomer was confirmed by 1 H NMR, 13 C NMR, FT‐IR, and high‐resolution mass spectrometry. The curing kinetics of EQ‐tma were investigated by non‐isothermal DSC, and the apparent activation energies determined by the Kissinger, Ozawa, and Starink methods were 93.94, 97.21, and 87.50 kJ/mol, respectively, indicating that the curing reaction followed an autocatalytic model, and the kinetic equation was accordingly established. EQ‐tma was then blended with commercial PH‐ddm, and the curing mechanism of the blends was studied by in situ FT‐IR. TGA analysis demonstrated that the incorporation of EQ‐tma improved the thermal stability of the commercial benzoxazine, while DMA was employed to evaluate the thermomechanical properties of the resultant co‐polymers. This study provides new insights into the molecular design of biobased benzoxazines and reveals their formulation potential when blended with benzoxazine commercial system.