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Determination of activation energy during the thermal degradation of Polyamide 66/glass fiber composites

The objective of this study was to clarify the mechanical properties and the non-isothermal degradation kinetics of Polyamide 66 (PA 66)/glass fiber (GF) composites. The non-isothermal degradation behavior of the samples was studied by thermal gravimetric analysis under nitrogen purge. The perfect compatibility of GFs with polymer matrix in composites was studied by scanning electron microscopy. It was found that with increasing content of GFs in samples due to good distribution of fibers in PA 66, the degradation temperature and calculated activation energy in composites increased in all heating rates. The activation energy was calculated by the Flynn–Wall–Ozawa method (isoconversional method). It was concluded that the model-free methods can be a reliable way to determine the kinetic parameters. Furthermore, the isokinetic relationship was used to estimate a model-independent pre-exponential factor (lnA) corresponding to a given degree of conversion.