Thermokinetic studies of poly(o-toluidine) doped with perchloric acid
Thermokinetic parameters of the solid-state of poly(o-toluidine) (POT) doped with perchloric (HClO4) acid was studied by thermogravimetric analysis (TG) and differential thermal analysis (DTA) under non-isothermal conditions. Molecular mechanics (MM) calculations suggest that the optimal geometric structure (OMG) of the HClO4-doped POT is at least four orders of magnitude more stable than the molecular geometric (MG) structure. These calculations indicate that the potential energy (PE/kJ mol−1) of the OMG is about four (1.09·104) orders of magnitude lower than the MG structure of the same matrix. The empirical formula of the doped polymer is best represented by [POT-2HClO4·2H2O]n as substantiate by elemental analysis and MM calculations. The full polymer decomposition and degradation were found to occur in three stages during the temperature increase. The decomposition activation energy (E d) of HClO4-doped POT matrix was calculated by employing different approximations. The heating rate (α) of the decomposition and the frequency factor (K o) were calculated. A number of equations were used to evaluate the kinetic parameters. The mechanism of the degradation of the conducting polymer is explained on the basis of their kinetic parameters. A remarkable heating rate dependence of the decomposition rate was observed.
KeywordsDTA elemental analyses molecular mechanics calculations poly(o-toluidine) thermal degradation
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