Curing mechanism and kinetics of benzoxazine co-catalyzed by transition metal salt and phenolic resin

Benzoxazine is widely used in halogen-free copper clad laminate, printed circuit board and other fields in electronic information industry. However, its high curing temperature (about 250 °C) limits its future application. The effectiveness of benzoxazine catalyzed by transition metal p-toluenesulfonate(M(OTs)n) and linear phenolic resin(PF), separately and mixed, were studied by DSC. The curing mechanism, structural changes and curing kinetics of different catalytic systems was studied by In-situ FT-IR and nonisothermal Differential Scanning Calorimeter(DSC).The results show that M(OTs)n and PF can simultaneously exist in benzoxazine as catalyst, and the catalytic ability is the strongest. The kinetic data shows that the introduction of catalyst can change the curing reaction mechanism of benzoxazine from autocatalytic curing reaction model to n-order reaction model. It follows the n-order reaction kinetic model based on Malek and Friedman method, and the theoretical calculation curve is in perfect accordance with the experimental data.