Preparation And Properties Of Regenerated Silk Fibroin Materials

Regenerated silk film of Bombyx Mori was prepared using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) as cross-linking agent and N-hydroxysuccinimide(NHS), 2—morpholinoethanesulfonic acid (MES) as assistant on the principle of laminating and hot air dryness. The cross-linked film was characterized using XRD, FT-IR and Raman. The solution losing, tensile strength at break, elongation at break and Young modulus of cross-linked film were tested and analyzed. The results showed that there were more silkⅠin cross-linked film when adding 10-15% (relative to silk fibroin quantity)EDC using laminating and hot air dryness. But the quantity of silkⅠshould not increase when the percentage of EDC was higher than 15%. The solution losing and Young modulus of cross-linked film decreased remarkably when adding 15-20% (relative to silk fibroin quantity)EDC, while the elongation at break increased remarkably. NHS and MES could strengthen the effect of cross-linking as assistant.Silk porous Material was prepared by cross-linking silk fibroin solution and EDC, NHS, MES on the principle of freeze-drying. The solution losing, porosity, the average pore diameter, density, compression were tested and analyzed. The results showed that the molecular conformation of silk porous material is mostly amorphous. The pore diameter, porosity , solution losing percentage in hot water and compression of silk porous material declined with the fall of temperature and the rise of silk fibroin solution's concentration. By changing the technical condition, we could prepare the silk porous film with the average pore diameter from 30.8μm to 282.8μm , the porosity from 59.7% to 90.9% , the density from 0.071 g/cm3 to 0.207 g/cm3 , the compressibility from 6.0% to 24.1% and the solution losing percentage in hot waterfrom 27.6% to 6.03%.The suitable method to dissolve Antheraea Yamamai silk fibroin fibers and the method to prepare regenerated silk fibroin were investigated. Antheraea Yamamai silk fibroin film was prepared on the principle of laminating and hot air dryness. The molecular configuration of silk fibroin in the film treated by ethanol with different concentration was characterized using XRD, FT-IR and Raman. The results showed that calcium nitrate and lithium thiocyanate dense solution were good solvent for Antheraea Yamamai silk fibroin fibers, the lithium thiocyanate dense solution with high concentration could dissolve Antheraea Yamamai silk fibroin fibers preferably at 35℃,1 h. There were mainlyαstructure and random coil in the Antheraea Yamamai silk fibroin solution, and that's same in the regenerated silk fibroin film using laminating and hot air dryness. Theαstructure and random coil should change toβ-sheet structure in the film after treating by 60-80 % ethanol, 1 h. It could enhance the water repellency of the film remarkably.