Strength function limiting behavior

In principle, the A 0(H) function is of limited interest for kinetic applications because the indicators are chemically very different from the organic substrates generally used. On the other hand, as the measurements are based on pH determination, the length of the acidity scale is limited by the pA" value of the solvents. However, very interesting electrochemical acidity studies have been performed in HF by Tremillon and co-workers, such as the acidity measurement in anhydrous HF solvent and the determination of the relative strength of various Lewis acids in the same solvent. By studying the variation of the potential of alkane redox couples as a function of acidity, the authors provide a rational explanation of hydrocarbon behavior in the superacid media.48... 

Electrical degradation and breakdown phenomena [23] limit the utility of polymers in many applications ranging from electrical cable insulation to uses in advanced electronic devices. The key property of a polymer in relation to its electrical degradation and breakdown behavior is its dielectric strength. This property cannot be predicted quantitatively as a function of the polymeric structure at this time. However, because of its importance, we will discuss it briefly. 

The most important effect of plasticization is the lowering of the Tg of the polymer, which was discussed in Section 6.D. Another effect of plasticization is that the activation energy for viscous flow of the solution at T>1.2-Tg is usually smaller than the activation energy of the pure polymer since ET)p Er S for most polymer-solvent combinations. Our preliminary calculations show that Equation 12.21 may often be preferable to Equation 12.19 for describing the behavior of Er SS, at least for Op l. This issue must, however, be considered in greater detail in order to reach more definitive conclusions. In particular, ET SS must be examined as a function of Op in the limit of Op—>1. Furthermore, the dependence of the behavior of ET SS as a function of Op on the strength of the interactions between the polymer and the solvent needs to be considered. 

---