Polyani-Semenov rule

Defining the activation energies according to Polyani-Semenov rule (20) we find... 

It is improbable that the value of the preexponential coefficient would exceed the frequency factor by one or two orders of magnitude. Possibly the reason for the abnormally high steric coefficient in Reaction 1 is its deviation from the Polyani-Semenov rule, although the activation energy calculated by Moin (15) gives the same result within the limits of the precision of this method. In any case, the low limit of the activation energy of the Voevodsky reaction is its thermal effect. Accepting the fact that Reactions 3 and 8 proceed without an activation barrier, P3 = 0.2 and P2 0.03. 

Lachinov and co-workers [52] have performed a more detailed study of the kinetics of block radical polymerisation of perfluoroalkylmethacrylates (FMA) in the solid state. The main method of investigation of the kinetics of FMA polymerisation was isothermic calorimetry [58]. Due to the absence of data on the heat effects of their polymerisation in the reference literature, these values were measured [52]. The values of AQ and glass transition point (T ) of polymers formed are shown in Table 8.3. Obviously heat of polymerisation of monomers of the fluoroacrylate sequence is quite close to heat of polymerisation of non-substituted monomers of the AMA sequence [59], and a significant influence of the length of the fluoroalkyl radical on this parameter is absent [52]. In accordance with the Polyani-Semenov rule, the present result makes it possible to consider that chain propagation constant of FMA with the accuracy of the pre-exponential multiplicand being equal to each other [57]. 

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