engleski

Strategy for kinetic parameter estimation - thermal degradation of polyurethane elastomers

The kinetics of the thermal degradation of polyurethane elastomers (PU) based on poly (ether polyol) soft segment and aromatic type of diisocyanate (MDI) was investigated by thermogravimetric analysis (TGA) under the nitrogen atmosphere employing four different heating rates. The corresponding kinetic parameters of the two degradation stages were estimated by minimising the output error functional and by the Kissinger method. In evaluation of kinetic parameters of the two-step PU thermal decomposition, differential thermogravimetry (DTG) curve is applied as objective functional in regression procedure. Parameter estimation is obtained by minimising the weighted quadratic output error functional with the modified Nelder-Mead simplex search algorithm. The confidence regions in the pre-exponential factor-activation energy space are established for both the first and second stage of degradation. The effect of the soft segment molecular weight and hard segment content on the activation energy of the degradation process was constructed by response surface methodology.

thermal degradation; polyurethane elastomers; kinetic parameter

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