Arrhenius equation thermal degradation

Thermal Stress. The Arrhenius equation states that a 10°C increase in the temperature doubles the rate of most chemical reactions. However, this approach is generally only useful to predict a product s shelf life if the instability of the emulsion is due to a chemical degradation process. Furthermore, this degradation must be identical in mechanism but different in rate at the investigated temperatures. Thus, the instability of... 

Sande (98) reported that temperature is not expected to affect the absorption of photons as such, and no additional energy is needed for the reaction to take place. However, the temperature will affect subsequent chemical degradative reactions in the usual manner as described by the Arrhenius equation. If a secondary thermal reaction is involved, a temperature effect on the overall reaction quantum yield would be expected. A change in the viscosity of the liquid as a result of increase of room temperature can influence the rate of photochemical degradation. 

Moreover, the data obtained from TGA are susceptible to be study mathematically in order to quantify the kinetics of the thermal degradation. These studies became very interesting in order to determine the improvement reached in the thermal stability provoked by the addition of additives or by modifying the initial PU. Assuming the degradation process is thermally activated, the TGA data can be fitted as Arrhenius equation (Eq.l)[ll] ... 

An adaptation of the Arrhenius equation referred to as the Kissinger method [32] was employed for this analysis. Determination of the activation energy for thermal degradation of polycarbonate-acrylonitrile-butadiene-styrene copolymer-montmorillonite composite when compared to the polymer blend without montmorillonite provided a similar trend... 

In the simplest case, if viscoelastic behavior and degradation are taken as thermally activated molecular processes with constant activation energy, the Arrhenius equation can be used to estimate long-term changes in an elastomer [8], Reaction rate data for an elastomer property are obtained at a series of elevated temperatures under otherwise constant conditions and plotted as described earlier. The plot can then be used to estimate changes at long periods of time at reduced temperatures. 

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