Effect of the Coagulation Bath Composition on the Spinnability of Casein Solutions

The results of determining the maximum fiber take-up velocity (MTV) were used in studying the effect of temperature and composition of the coagulation bath (bath I - a CaCl₂ solution with a concentration of 22.2 to 244.2 g/1 and pH 0 to 7.5; bath II - a NaC1 solution with a concentration of 0 to 306.8 g/1 and pH from o to 2.0) on the spinnability of casein solutions. For both baths, the dependence of the MTV on pH and salt concentration are of extreme nature. As the temperature rises, the difference between the values of the MTV and linear jet speed at the exit from the spinneret increases exponentially. A correlation between the temperature coefficient of this value and the apparent enthalpy of viscous flow of the spinning solution has been established. Hence, it is assumed that the effect of temperature on spinnability is due to the effect of temperature on the viscosity of the spinning solution. The obtained results have been considered in terms of HAN'S theory of spinnability with due account for the nature of the processes leading to gelation of the protein solution jet in the coagulation bath.