Benzoxazine Resins Containing Trifluoroacetylamine: Preparation, Curing Kinetics, and Thermal Properties

ABSTRACT In order to reduce the polymerization temperature of conventional benzoxazines, three single‐functional benzoxazines (TF‐EBA, TF‐FBA, and TF‐PBA) containing trifluoroacetylamino groups were synthesized. The molecular structures of TF‐EBA, TF‐FBA and TF‐PBAwereconfirmed by Fourier Transform Infrared Spectroscopy (FT‐IR) and protonNuclearMagnetic Resonance ( 1 H NMR). The curing kinetics of the TF‐BA resins were analyzed by Kissinger and Ozawa methods. The activation energies for the polymerization of TF‐EBA were 80.80 and 84.70 kJ/mol, respectively, which were determined by the Kissinger and the Ozawa methods. The curing behavior was analyzed by Differential Scanning Calorimetry (DSC) and FTIR. After 170°C/1 h + 200°C/3 h heat treatment, the TF‐BA resins were cured completely. Meanwhile, the thermal stability of TF‐BA benzoxazine polymers was evaluated by Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA). The glass transition temperatures ( T g ) of the three TF‐BA resins all exceed 200°C. Among them, the T g of TF‐EBA is 276°C, and the T g of TF‐FBA is 282°C. Under N 2 atmosphere, the char yield ( Y c ) of all TF‐BA resins at 800°C is more than 40%. In summary, this study conducted a detailed discussion on the curing kinetics and thermal stability of monofunctional benzoxazines containing trifluoroacetyl amino groups, and it has certain reference value for related work.