A COMPARATIVE-STUDY ON K-THETA EVALUATION FROM [ETA]-M DATA IN SINGLE AND MIXED-SOLVENTS THROUGH VARIOUS EXCLUDED VOLUME THEORIES

By allowing for the dependence of B on molecular weight, through its relationship with A2, modified Flory-Fox-Schaefgen, Kurata-Stockmayer-Roig, Berry and Inagaki-Suzuki-Kurata equations are obtained, relating [eta] to A2 and to K-theta. Through these equations, K-theta can be determined from data sets for [eta]-A2. Because of the scarcity of these data sets, A2 values have been calculated from experimental data for [eta] and trial K-theta values through two parameter theories, namely, through the Flory-Krigbaum-Orofino theory for PSI. Iterative processes were followed until coincidence was obtained between trial K-theta values and those evaluated from the modified excluded volume equations. The method has been applied to K-theta evaluation for various literature data for [eta] of polystyrene, poly(methyl methacrylate), poly(dimethyl siloxane), poly(2-vinyl pyridine) and poly(vinyl pyrrolidone). A discussion on the reliability of the above excluded volume theories on the basis of obtained K-theta values and slopes, as well as on the observed deviations, is undertaken.