Method of Multiple Heating Rates

If the value of the constant heating rate is changed between runs with other conditions being identical, different TGA curves will be obtained. From Equation 1.8 it can readily be shown that  

To evaluate n, we may employ the following expression which applies at In = 0  

In this case, a plot of E/RT versus In W should give a linear relationship whose slope will be n. 

Studies have been conducted involving graphical methods based on variable heating 

Another approach to the measurement of the isothermal life of a polymer is the use of the equation  

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The kinetics of the cure of ATS at 130°C in nitrogen determined by various methods are shown in Figure 1. The dashed curve represents the prediction based on kinetic parameters determined by analysis of scanning DSC data by the method of multiple heating rates described previously (8). This method utilizes a rate equation of the form ... 

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