Viscosity and light scattering measurements of poly(tetrahydrofuran) were carried out in various solvents, involving a mixed theta solvent. The intrinsic viscosity vs. molecular weight relationships obtained in the range of molecular weight from 3.5·10 4 to 1.1·10 6 were : [η] = 1.31·10 −3 M̄ w 0.60 in benzene (30°C.), 1.76·10S−3M̄ w 0.54 in a mixed theta solvent of ethyl acetate (22.7 wt.‐%) and n ‐hexane (77.3 wt.‐%) (31.8°C.), repectively. The recent x 3 treatment of the viscosity data lead to the following values of the conformational parameter σ which was defined as the ratio of the end‐to end distance of the polymer in the unperturbed state to that in the freely rotating state: σ = 1.85 in benzene, 1.70 in cyclohexane. 1.58 in ethyl acetate, and 1.64 in the theta mixture. Effect of benzene on the chain conformation was notable. This polymer was prepared by bulk polymerization at 0°C. with an aluminium triethyl and water catalyst and the ratio of the weight average to the number average molecular weights was about 1.04 as was determined by the sedimentation velocity analysis.
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Kurata et al. (1965) studied this question.