STUDIES ON THE PRODUCTION OF ACRYLIC FIBER BY WET SPINNING

(2) ON THE COAGULATION VALUE AND THE CRITICAL CONCENTRATION OF ACRYLIC AN-MA COPOLYMER IN SOLUTION

Abstract

Acrylonitrill (AN)-methyl acrylate (MA) co-polymers in which contents of MA varied from 0 to 15, wt. %, were dissolved in 50 wt. % NaCNS aqueous solution to make 1% polymer solution at 30°C. 10cc. of them were titrated with 0, 6, 11, 16, wt. % NaCNS aqueous solution at 5-10°C or 18-20°C. In this report, the amount of precipitant just to make polymer precipitated is called coagulation value or the point of turbidity. The critical concentration is expressed with the concentration of NaCNS, wt. % based on liquid phase at the point of turbidity.
It was found that the coagulation value increases as the concentration of NaCNS in the precipitants and the MA content in the copolymer increase. The critical concentration of NaCNS in liquid phase is reversely proportional to the MA content in polymer. That is, each copolymer has its own critical concentration, depending on the MA concentration.
Data of critical concentration shows that water is the most powerful precipitant. 6% NaCNS conc. aqueous solution is the second. 11 and 16% aqueous solution are mild.
It is noticed that the measuring temperature affects on the critical concentration.