Extraction and characterization of silk fibroin from waste silk

Waste silk fibers were dissolved in calcium chloride aqueous solution. Effect of calcium chloride concentration on silk solubility was studied. Dialysis method was used to purify the dissolved silk fibroin. The purified silk fibroin was characterized by FTIR. and thermoanalysis technique. Results showed that the purified silk fibroin mainly had irregular curly conformation. The glass transition temperature of the regenerated silk fibroin reached 90.6 degrees C-135 degrees C, higher than 78.9 degrees C-135 degrees C before purification. Thermal weight loss temperature by 50% was 490.3 degrees C differing from 429.7 degrees C before purification.