STRUCTURE AND PROPERTIES OF HIGH-SPEED SPUN FIBERS OF NYLON-6

Structure and properties of high-speed spun fibers of nylon 6 were stu died in the range of take-up speeds from 5 to 12 km/min. With increasi ng take-up speed, Young's modulus increased uniformly, while tenacity passed through a maximum at 8 km/min. WAXD data demonstrated the incre ase in the perfectness of the crystalline state with increasing take-u p speed. First, the gamma-form crystal structure predominated up to 9 km/min along with increase in its crystal size; second, in the range o f 9 to 12 km/min, the alpha-form crystal structure appeared and develo ped as reflected by the increase in its crystal perfection. The struct ure-properties relationships are discussed, and it is indicated that t he increasing tendency of Young's modulus over 9 km/min can be attribu ted to the development of the alpha-form crystals.