Non-Isothermal Curing Kinetics of Alkali-Treated Alfa Fibers/Polybenzoxazine Composites Using Differential Scanning Calorimetry

The exploration of curing process of benzoxazine resins, which possess outstanding features, is crucial for practical and advanced applications. In this study, bisphenol A-aniline based benzoxazine (BA-a) composites reinforced with alkali treated alfa fibers (TAF) were prepared. The influence of different loadings of the TAF on the curing kinetics of BA-a was investigated using non-isothermal differential scanning calorimetry (DSC) at different heating rates. Isoconversional integral methods or model free kinetics, namely, the iterative Kissinger-Akahira-Sunose (it-KAS), iterative Flynn-Wall-Ozawa (it-FWO), Sbirrazzuoli methodology (VYA/CE) and Trache-Abdelaziz-Siwani (TAS) methods have been applied to the experimental data in order to evaluate the curing kinetic parameters. The study revealed that the presence of TAF improved the crosslinking reaction of benzoxazine and reduced the activation energy. The pre-exponential factor exhibited the same trend as the activation energy. The reaction model, examined for all composites, showed that all systems were accurately presented by an autocatalytic reaction model. The Avrami-Erofeev model was the most appropriate for describing the cure kinetics and revealed a good agreement with experimental data.