Abstract
A study was undertaken to obtain useful fibroin powder from the silk wastes. For the preparation of silk fibroin powder, neither salts nor acids were used as solvents, but the wastes were solved in water under the high temperatures and dried to gain very high concentrated silk powder. Then the powder was further decomposd with proteolytic enzymes. The characteristics were identifed by means of the solubility, DSC, GPC, and XRD. The composition of the silk powder was confirmed by the amino acid analyzer. It was found that the endothermic peak wasreduced as the increase of decomposing temperatures and hours at about 33$0^{\circ}C$, the molecular weight distribution showed a reducing tendency, the second decompositions were less molecularized by 20% than the first ones, the average molecular weight of 4,700 was shown in the second treatments, the X-ray diffraction showed the crystalline structure transformation between second treatments, the X-ray diffraction showed the crystalline structure transformation between silk I and II types, and the composition of amino acids was nearly identical regardless of decomposition methods and conditions.
