Study On The Dry Wet Spinning Of Regenerated Silk Fibroin Fibers

With the enhancing awareness of green environment protection consciousness ofpeople, and the excellent characters of the regenerated protein fiber such as the goodbiocompatibility, healthy, care-skin, and so on, the development of the regeneratedsilk fibroin (RSF) fiber has attracted more attention. The spinning solution was basedon abandoned fibroin fibers, the spinning process of coagulation bath, predrawingbath, hot washing bath was adopted to realize the silk fibroin fiber regeneration by drywet spinning method. The coagulation bath, predrawing bath, hot washing bath to theregenerated protein fiber were researched.The research showed: the concentration of ammonium sulfate was40%, thetemperature was about15℃,the height of air layer was3centimeter, the spinneretdraw-ratio was2. The concentration and temperature of coagulation bath affect theas-spun fiber through double diffusion. When the fiber solidification was slow, thestructure of as-spun fiber would become denser and the skin-core structure would beimproved. When the height of air layer was3centimeter, the as-spun fiber wassmoother than the wet spinning, Conversely, the orientation and disorientation gotbalanced, the mechanical properties was greatly improved. When the spinneretdraw-ratio was2, the spinning was steady.The optimum parameters of predrawing bath were: the concentration of ethanolwas5%and lithium bromide was2%, the temperature was15℃. When thedraw-ratio in the predrawing bath was2.2, the degree of orientation was higherthrough observing the polarization microscope and X-ray diffraction.When the temperature was70℃in the hot washing bath, the draw-ratio washigher. With the increase of draw-ratio, the surface grooves, cracks of fibers would be gradually reduced until smooth, and the internal voids would be gradually decreasedor even disappeared, the boiling water shrinkage would reduce, the structuredimension would become more and more stable. However, the molecularconformation had been unchanged substantially which was still α-helix and randomcoil structure-based, the coexistence of a small amount of β-sheet structure, the crystalstructure which was still a large amount of unstably SilkⅠstructure.