Abstract
A convenient and reliable method for evaluating fiber strength of soy protein dope during spinning was studied. The method applied to calculate the drags received by cylindrical body moving in the stationary fluid could be conveniently used to calculate the fiber strength during spinning. The spun-fiber strength was proportional to the protein concentration in dope. Finally fibers could not be spun when dope was prepared with less than 1.0% NaOH(pH12.20), and viscoelasticity of dope slightly increased with the laps of time and gel formation also increased. But, on the contrary, when dope was prepared with more than 1.1% of NaOH concentration(pH12.45), the viscoelastic value of dope decreased with the laps of time and showed the fluidity. By incubating dope with more than 1.1% NaOH, maturation effects could be obtained; when the dope was prepared with 1.5% NaOH(pH13.1)and incubated at 50°C for 30min, the spun-fiber strength was the highest. Ad-justing the NaOH concentration to over 1.6%, no maturation effects could be observe, and the viscoelastic value and strength of the fiber were also decreased, since dope changed to sol state and the molecular weight of the protein decreased.
