6533b7dbfe1ef96bd1271339

RESEARCH PRODUCT

A comparative study on Kθ evaluation from [η]-M data in single and mixed solvents through various excluded volume theories

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Abstract 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 [η] to A2 and to Kθ. Through these equations, Kθ can be determined from data sets for [η]-A2. Because of the scarcity of these data sets, A2 values have been calculated from experimental data for [η] and trial Kθ values through two parameter theories, namely, through the Flory-Krigbaum-Orofino theory for Ψ. Iterative processes were followed until coincidence was obtained between trial Kθ values and those evaluated from the modified excluded volume equations. The method has been applied to Kθ evaluation for various literature data for [η] 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 Kθ values and slopes, as well as on the observed deviations, is undertaken.