Abstract
Wet spinning of nylon 6 was studied by using 90% phenol aqueous solution as solvent and NaOH aqueous solution as coagulant. The optimum spinning conditions obtained for molecular weight of 3×104, nozzle of 0.5mmφ, coagulating bath length of lm and spinning speed of 10m/min, are as follows; coagulating bath temperature: 50°C, coagulating bath concentration: 4% and polymer concentration: 20%. Side and cross-sectional microscopic features, density, area ratio and mechanical properties of the wet spun filaments are considerably affected by spinning conditions. Molecular weight of polymer has also a large effect on spinnability, and in the case of nylon 6, molecular weight required for good mechanical properties is more than 2×104. Wet-spun filament can be drawn about 6 times in water at 65°C in spite of its higher density and crystallinity, and oriented X-ray fiber diagram is obtained for drawn and heat treated samples.
It is concluded that when spinning, drawing and heat treatment conditions are chosen adequately, the wet-spun fibers have good mechanical properties as that of the melt spun fibers. In addition, dyeing rate and moisture regain of wet spun fibers are larger than those of melt spun fibers. The cause of this behavior is discussed in terms of the cross-sectional and fine-structural characteristics of the wet-spun fibers.
