Influence of the Thermodynamic State of Bisphenol a and Aliphatic Epoxy Oligomers on the Temperature Dependences of Newtonian Viscosity

Abstract

A generalised analysis is made of experimental and published data on the temperature dependences of the Newtonian viscosity of bisphenol A and aliphatic oligomers of different molecular weight in a wide temperature range, with account taken of the departure of the experimental temperature from the hypothetical (calculated) crystallisation temperature Tcr. It is shown that the deviation of the temperature dependence of the Newtonian viscosity of epoxy oligomers from the theoretically expected dependence in accordance with activation theory and free volume theory is greater the lower the temperature range of the experiment by comparison with Tcr, and accordingly the greater the probability of formation of solid-like molecular associates or clusters. The use of Tcr as a parameter of the corresponding state (the temperature of reduction) makes it possible to plot a “universal” generalised curve of viscosity for epoxy oligomers with account taken of the dependence of their Newtonian viscosity on molecular weight.