DRAWING AT WET-SPINNING OF POLY (GLUTAMIC ACID) FIBERS

A conc. aqueous solution of poly (sodium-L-glutamate) (PSLG) was spun in aqueous acid solutions. The effect of drawing conditions including the drafting, spinning-drawing and after-drawing were discussed in relation to the molecular chain conformation, crystal-type and mechanical properties of the resulting fibers. Drafting; When the H3PO4 solution was used as a coagulant, not only the extruded fluid filament became thinner, but also the molecular chains were extended and the β-type crystals were formed in the drafting process. When the HCl solution was used as a coagulant the α-type crystals were formed. Spinning-drawing; The spinning-drawing process was carried out after the drafting. The semicoagulated filaments were drawn between the 1st and the 2nd rollers above the coagulation bath. When the H3PO4 solution was used as a coagulant, the β-type crystals were formed and highly oriented. On the contrary, the HCl solution was used as a coagulant, the α-type crystals were formed and slightly oriented. After-drawing; The filament containing H3PO4 was wound up on a bobbin. The α-type crystal was formed in the filament. In the after-drawing process, the filament was drawn between two rollers in air, in a H3PO4 solution or in water at various temperatures. When the after-drawing was carried out at temperatures below 70°C, the filament superior in quality was obtained, and the β-type crystal was formed in the drawn filament which was highly oriented. Whereas, the after-drawing was carried out at temperatures above 70°C, the filament was broken. The filament with excellent mechanical properties was obtained by the combination of the drawing processes in the drafting and in the spinning-drawing.