Abstract
The rheological properties of $\alpha$-and ${\gamma}$-keratoses prepared from Merino wool by oxidation with performic acid were examined by using the cone and plate rheometer. Steady shear rate viscosity, dynamic viscosity, and dynamic storage modulus have been measured for keratose solution containing 7.5-20.0g/dl keratose in aqueous soidum tetraborate buffer solution. Measurements were carried out over a shear rate range of 0.75-600 sec-1 to obtain steady rate viscosity, and dynamic properties were measured by oscillatory shear over a frequency range of 0.006-2.2rad/sec. Significant difference in rheological properties between two fractions of oxidized wool was found. $\alpha$-keratose solution showed the non-Newtonian behavior, whereas ${\gamma}$-keratose solution revealed nearly the Newtonian behavior below the critical concentration(Cc) of 12.5g/dl at which ${\gamma}$-keratose seemed to start to form an aggregate. It was also found that zero shear rate viscosity was markedly dependent on the concentration of both the fractions, suggesting the presence of strong interaction between the molecules in solution, with the 8th and 11th powers of concentration above Cc for $\alpha$-and ${\gamma}$-keratose solutions, respectively. These were closely considered in connection with wool structure.