Lyocell凝固丝的结构及其对后拉伸性能的影响OA

To clarify the structure of Lyocell coagulated filament and its influence on post-drawing property,two-stage drawing process was designed to prepare high-performance Lyocell fiber.A series of Lyocell coagulated filaments were prepared by changing the mass fraction of the coagulation bath.The structural characteristics and extensibility of Lyocell coagulated filaments were analyzed using scanning electron microscopy,X-ray diffraction,birefringence,stress-strain and online stretching methods.The property of Lyocell filaments prepared by two-stage stretching process and one-stage tensile process were compared.The results showed that as the mass fraction of the coagulation bath increased,the solvent mass fraction in the coagulated filaments was increased,forming an ultramolecular structure with smaller grain size,lower crystallinity and orientation degree.However,the elongation at break and the second stage maximum draw ratio of coagulated filaments showed a pattern of increasing first and then decreasing.Under the same total draw ratio,compared with the filaments prepared by one-stage drawing process,the breaking strength of the filaments prepared by the two-stage drawing process was increased by approximately 25%.