Temperature and Humidity Effects on Degradation

In conunon with all chemical reactions, the rate of oxidative degradation also increases with the temperature of the substrate (Andrady et al., 2003). The magnitude of acceleration depends on the activation energy of the degradation process. The common form of the Arrhenius equation relates the rate constant k of a reaction to the 

The Equation 6.2 must be applied with caution as the rate must be time independent for the expression to apply. Kinetics of polymer degradation can change at T Tg (°C) therefore, values of E determined below Tg cannot be assumed at be the same at r Tg (°C). If the mechanism of degradation changes with temperature, Equation 6.2 cannot be used to estimate the value of AE. Typical values for AE for unstabilized PP was reported to be 27kJ/mol (Frangois-Heude et al., 2014). 

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