Synthesis and curing kinetics of benzoxazine containing fluorene and furan groups

A novel benzoxazine bearing fluorene and furan group (B-bff) was prepared using 9,9-bis(4-hydroxyphenyl) fluorene, furfurylamine and formaldehyde as raw materials. The chemical structure of B-bff was characterized with FTIR, 1H NMR, 13C NMR, and elemental analysis. The curing reaction was investigated under non-isothermal differential scanning calorimetry (DSC) at different heating rates. The apparent activation energy of the curing reaction was determined to be 119.1 kJ mol−1 and 121.3 kJ mol−1, respectively, according to Kissinger and Ozawa method. Isoconversional analysis of the DSC data showed that the activation energy value decreased with the degree of conversion. The autocatalytic kinetic model was found to be the best description of the investigated curing reactions. In addition, the predicted curves from our kinetic models fit well with the non-isothermal DSC thermograms. Thermogravimetric analysis (TGA) result showed that the cured polymer possessed good thermal properties with the 5% weight loss temperature 402 °C and char yield at 900 °C 57%.

Research highlights▶ In this manuscript, a novel benzoxazine bearing fluorene and furan group (B-bff) was prepared using 9,9-bis(4-hydroxyphenyl) fluorene, furfurylamine and formaldehyde as raw materials. ▶ The curing reaction was investigated by non-isothermal differential scanning calorimetry (DSC). ▶ The apparent activation energy of the curing reaction was determined to be 119.1 kJ mol−1 and 121.3 kJ mol−1, respectively, according to Kissinger and Ozawa method. ▶ Isoconversional analysis of the DSC data indicated that the activation energy value decreased with the degree of conversion. ▶ The autocatalytic kinetic model was found to be the best description of the investigated curing reactions. ▶ Thermogravimetric analysis (TGA) result showed that the cured polymer possessed good thermal properties.