Dilute‐Solution Dynamic Viscoelastic Properties of Cellulose Tricarbanilates

Abstract

The frequency dependences of the storage and loss shear moduli, G′ and G″, of dilute solutions of three cellulose tricarbanilate fractions in tetraethylene glycol dimethyl ether were measured at 25.0°C by the Birnboim‐Schrag multiple‐lumped resonator. The frequency range was 100 to 5800 Hz and the concentration range 0.5 to 3 g/L. The weight‐average molecular weights were 0.4, 0.8, and 1.1×106. Intrinsic viscosities were determined by capillary viscosimetry. For interpretation of the results, the bead‐spring coil model and the Yamakawa‐Yoshizaki theory for the intrinsic viscosity of helical wormlike chains were modified to take into account a moderate degree of molecular weight heterogeneity with assumption of a Schulz‐Flory distribution. The viscoelastic data could be fitted by the bead‐spring model with the hydrodynamic interaction parameter h*=0.15 or 0.05 and Mw/Mn=1.3. From the intrinsic viscosities, the persistence length was calculated from the Yamakawa‐Yoshizaki theory as 10 nm for all three samples, much smaller than those of semiflexible rodlike molecules previously studied.