Abstract: Regenerated silk fibroin fibers with remarkable mechanical properties were successfully prepared via wet spinning technique, based on the high concentration and high molecular weight silk fibroin aqueous solution as spinning dope. With the observation of SEM, it could be found that the cellular structure may exist in the core of as-spun fibers. The regenerated silk fibers exhibited a smooth surface and dense structure after the post-drawn process. The NMR and Raman spectra results reveal that the β-sheet content increased with the increase of drawn ratios. It was also found that the steam-annealing can further improve the orientation of the macromolecular chains in the fibers. After the post treatment(both post-drawn and steam annealing), the breaking strength and the elongation at break can reach 0.5 GPa and 22%, separately, which is close or even better than that of natural silk(cocoon) fibers.

Key words: Silk fibroin, Artificial spinning, Post-drawn, Conformation, Mechanical property