Preparation Of RSF Fibers Using Self-dialysis Process And Their Structure And Properties

The degummed silk fibroin (SF) was dissolved in the mixed solvents of LiBr/EtOH and LiBr/EtOH/EDTA (EDTA contents were 0.02, 0.04, 0.06wt%), respectively. Then the dopes were wet-spun by self-dialysis process to obtain uniform RSF fibers in this paper. The results showed that minim EDTA in the system could not only reduce crystallinity of RSF which was good to biodegradation but also improve strength-at-break of RSF fiber, which gave theoretical and experimental support to the study on RSF used as biomedical material. And it was the innovation of this paper. The experiment was divided into three parts: Firstly, the preparation and properties of RSF solution was discussed. The results showed that solubility of SF in LiBr/EtOH/EDTA system was superior to solubility in LiBr/EtOH system. Swelling time and heat-up temperature influenced solubility of SF. In order to obtain dope with good formation property, swelling time was made 6h or more and heat-up temperature was 75℃. Secondly, spinnability of SF dope was studied. The results indicated that the higher concentration of the dope and the less content of H2O would result in the better spinnability. And higher concentration of the dope had good spinnability whether the dissolution system containing minim EDTA or not. Pure EtOH and LiBr/EtOH (40/60, w/w) were used as solvent, to which minim EDTA was added. Then certain degummed SF was dissolved in the above mixed solvents to prepare the dope (21.7wt%) containing minim EDTA or not, respectively. Thirdly, the structure and properties of RSF fibers were investigated through SEM, X-ray diffraction, FTIR, Raman spectrum, TGA, electron single-fiber tensile tester. The results showed that RSF had more β-sheet structure, lower crystallinity (as-spun fiber:27.8%) and better strength-at-break (drawn fiber: 0.74cN/dtex for draw ratio 1.5) while the content of EDTA in the solvent was 0.04wt%.