Effect of Composition Ratio on Properties of Self-Crimping Bicomponent Fibers Composed of Polyamide 6 and Thermoplastic Polyamide Elastomer

Self-crimping bicomponent fibers have been widely used in textile products to improve properties, such as elasticity and fluffiness. So far, although many polyester-based self-crimping bicomponent fibers have been developed, polyamide (PA)-based ones are rarely reported. In this paper, self-crimping bicomponent fibers with PA/thermoplastic PA elastomer (TPAE) ratios of 35/65, 40/60, 45/55, and 50/50 were fabricated via melt spinning, and the effect of composition ratio on the properties of the fibers was investigated. The cross-sections of PA/TPAE bicomponent fibers varied from eccentric sheath-core to side-by-side, therein PA/TPAE interface changed from a curve to a straight line. The results showed that the increase in PA content contributed to the improvements in crystallinity, orientation, tensile tenacity, and thermal shrinkage strength, while that in TPAE content to the improvements in thermal shrinkage rate and elastic recovery rate. PA/TPAE bicomponent fibers had moderate mechanical properties and excellent elastic recovery, and hence can meet the requirements for textile processing. It is also noticed that the crimp behavior of PA/TPAE fibers was deviated from that of polyester-based side-by-side fibers as well as the predictions from current theories. This paper provides a new way to producing self-crimping fibers, the proposed fabrication method is applicable for large-scale production.