A novel method for estimating unperturbed dimension [η]θ of polymer from the measurement of its [η] in a non-theta solvent

A novel method based on the Einstein’s viscosity equation modified by Guth–Simha–Gold and the model on concentration dependence of polymer chain dimension proposed in our previous study has been developed to estimate the unperturbed dimension, [η]θ, of a polymer (i.e., the intrinsic viscosity at theta conditions) from the measurement of the intrinsic viscosity, [η], at non-theta conditions only. The [η]θ values obtained in present method for polystyrene, poly(oxyethylene), poly(methyl methacrylate), poly(vinyl chloride) and poly(isobutene) are good consistent with their experimental values at theta conditions or with their calculated values according to Mark–Houwink–Sakurada equation at theta conditions by the aid of their Kθ and molecular weight.