Sustainable synthesis of a high-performance benzoxazine resin with intrinsic reprocessable: Curing kinetics, thermal properties and environmental benefits

In this study, a high-performance bifunctional benzoxazine monomer (designated as TDT-fa) was successfully synthesized via a two-step approach using eugenol, furfurylamine, paraformaldehyde, and 1,1,5,5-tetramethyl-3,3-diphenyl trisiloxane as raw materials. The chemical structure of the product was comprehensively characterized by nuclear magnetic resonance spectroscopy ( 1 H NMR and 13 C NMR) and Fourier transform infrared spectroscopy (FT-IR), confirming the successful synthesis of the target molecule. The curing kinetics behavior of TDT-fa was deeply studied by differential scanning calorimetry (DSC). The apparent activation energies of its curing reaction were calculated using the Kissinger method and the Ozawa method, with the values being 100.60 kJ/mol and 112.22 kJ/mol respectively. The two values were close. Further analysis was conducted using the Starink method, and the average apparent activation energy of the curing reaction was finally determined to be 111.14 kJ/mol. It was also confirmed that the reaction mechanism of this curing reaction conforms to the characteristics of autocatalytic reaction. The results of thermogravimetric analysis (TGA and DTG) show that the residual carbon rate (Yc) of TDT-fa at 800 °C in a nitrogen atmosphere is as high as 50.41%, indicating that this resin has excellent thermal stability. Furthermore, the solidified TDT-fa resin exhibits unique reprocessability. Under specific conditions, it can achieve nearly 100% reprocessability. This characteristic effectively addresses the environmental pollution problem caused by traditional benzene pyrazine resins after use, providing an important basis for its application in the field of high-performance and environmentally friendly materials.