Reaction kinetics apparent curing activation

Assuming co-reaction, the cure reaction of a mixture of bis(4-maleimido phenyl) methane and BACY was followed by FTIR [221]. The reaction kinetics, studied by DSC, suggested dependency of cure mechanism on blend composition. The apparent activation energy computed by the Prime method increased with BMI content. The rate maximum at a fractional conversion range of 0.32-0.33 indicated an autocatalytic nature of the reaction. The different pattern of activation energy with fractional conversion for two different blend compositions indicated non-identical cure mechanisms for the two compositions. The cyclot-rimerization of BACY occurred during the cure of a 1 2 molar ratio of BMI and BACY. Since activation parameters derived from DSC method are generally not consistent, and since the cyanate cure can be catalyzed by impurities present in BMI, which was not taken into consideration, the authors conclusions on the cure mechanism based on DSC kinetics can be erroneous. 

Let us consider here the effect of segmental mobility on curing rate. The Eiring theory of reaction rates, which considers formation and decomposition of an activated complex, can deal with the simultaneously occuring chemical kinetics and diffusion control characterized, respectively, by some rate constants k and kd. Under certain conditions (prevailing chemical kinetics or diffusion control), the apparent reaction rate constant, kapp, expressed via the Rabinowitch equation... 

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