Fibrillation behavior of silk fibers from Japanese-oak-silkworm, Antheraea yamamai

Silk fibers from japanese-oak-silkworm, Antheraea yamamai, were fibrillated via Japanese handmade-paper making method, and laboratory handsheets were made. Scanning electron microscopy showed that the occurrence of fibrillation followed by tangling between the flbrils is important for the formation of sheets. The morphologies of the fibrils obtained through the fibrillation were investigated by transmission electron microscopy. Two types of fibrils, i.e. the ribbon-like ones and the random-coil-like ones were observed. The wide-angle X-ray diffraction measurement for these fibrils showed an amorphous scattering curve. However, no difference was observed between the infrared spectra for these fibrils and the control fibroin. It seems that the lateral packing of pleated beta sheet structure of fibroin of Japanese-oak-silk is loosened slightly when the fibrillation proceeds to a certain degree.