Estimating errors in the determination of activation energy by advanced nonlinear isoconversional method applied for thermoanalytical measurements performed under arbitrary temperature programs

摘要

In a previous paper (Thennochim. Acta 670 (2018) 1-6) it was shown that the estimation of errors (Delta E) in the determination of apparent activation energies (E) determined by a nonlinear isoconversional method applied for thermoanalytical measurements performed under constant heating rates involves the following successive steps: (1) the determination of Fisher confidence interval (Delta E-F) for confidence level of 95 % by applying the procedure suggested by Vyazovkin and Wight, and (2) the application of the relation: Delta E = 0.2447 x Delta E-F + 0.00037 x (Delta E-F)(2). The check of this procedure when using advanced nonlinear incremental isoconversional method (A-NL method) suggested by Vyazovkin is applied for thermoanalytical data under arbitrary temperature programs has been performed for: simulated sinusoidal modulated data, thermogravimetric (TG) data for thermal decomposition of a sort of high density polyethylene (HDPE) under quasi-isothermal conditions, and TG data corresponding to thermal decomposition of a sort of low density polyethylene under arbitrary temperature programs. It has been concluded that the suggested procedure for estimating the error in E evaluation based on above relationship is also applicable when A-NL method is used for kinetic analysis of thermoanalytical data recorded under arbitrary temperature programs.