Phthalonitrile-based resin for advanced composite materials: Curing behavior studies

Phthalonitrile-based resins play important roles in advanced materials due to their outstanding properties, which would be determined by the curing process and curing mechanisms. Thus, in this work the curing behaviors of phthalonitrile-based resin containing benzoxazine were investigated and the kinetic parameters were determined by non-isothermal differential scanning calorimetry (DSC) at various heating rates. Sequential double exothermic thermograms were separated by PeakFit v4.12 and analyzed as independent reaction processes. The kinetics model of each reaction was evaluated by multi-heating-rate DSC methods assisted with the iso-conversion method, and an autocatalytic model for the curing reaction of BA-ph resin was confirmed. The curing kinetics parameters including activation energyEα, pre-exponential factor A, reaction orders m and n were evaluated and calculated. The activation energies for reactions of benzoxazine and nitrile groups were 102.2 and 90.6 kJ/mol with reaction orders approximately 1.8 and 2, respectively. Additional, the predicated mathematical models for curing reactions of benzoxazine and nitrile groups were obtained and fitted well with the experimental data derived from the non-isothermal DSC thermograms.