Biomimic Artificial Spinning Of Regenerated Silk Fiber

Spider dragline silk has been noted for its excellent comprehensive mechanical properties in recent years, and sikworm silk was used as a luxurious textile material for a long history though it was thought traditionally not as strong as the former. However, from recent research we know that the mechanical properties of silkworm silk can be changed/improved by avoiding the weakness of the structure, and even as high as the spider's. In other hand, as more and more researches about the spider's spinning process and other outer conditions have been done, more and more usefull technology will be used on the spinning of regenerated silk fiber.In our experiment, we used the concentrated silk fibroin aqueous solution obtained from the abundant Bombyx mori silk fibers that given by the nature, (NH₄)₂SO₄ aqueous solution as coagulant and a homemade apparatus to produce high-performance regenerated silk fiber by wet spinning in order to examine the feasibility for the spinning of regenerated silk fiber in industry.From the research about the technologic parameters, we found that the concentration of the spinning dope play an important role on the feasibility of spinning. It is hard to spinning when the concentration is too high or too low, when the dope concentration is about 15%, the fiber is spinning continuously and both the surface and cross-section morphology are uniform and pretty well; In the other hand, the fiber's cross-section shape is most depend on the concentration of coagulant, and the fibers density is also depend on the temperature and the length of coagulation bath. The affect of post-draw under the air and steam conditions to the fibers' structure and properties were also discussed. And finally found a suitable technologic parameter for the spinning of thr regenerated silk fiber.We succesfully spun the regenerated silk fibers in a continuous process with an optimized technologic parameter. The as-spun fiber is formed with both silk I and silk II structure, with the increase of drawn ratio, the silk I structures converted into silk II structures. In other hand , the molecular chains of the regenerated silk fibers were more inclined to orient along the long axis with increase of the drawn ratio, especially under the steam annealing. The mechanical properties of regenerated silk fiber can been improved by the further treatment, which was superior to the native cocoon silk and close to the force-drawn silkworm silk fibers. In addition, the resulted regenerated silk fibers also presented controllable mechanical properties.Transfer mass ratio and the rigidity of the solidify surface were used to explain the form of the cross-section on the fiber. From the relation between the structure and mechanical property, a drawn mechanism under steam condition was approved.