Method of Freeman et al

From the experimentally determined curve giving the weight of polymer as a function of 1/T, the reaction rate as a function of 1/T can readily be derived (Fig. 14). If eqn. (72) is applied at two temperatures and the resulting expressions in the logarithmic form are subtracted from each other, 

A log Rt thus varies linearly with A log W for constant intervals A(l/T). The reaction order n is the slope of the line and E can be calculated from the intercept. 

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