Study of the structure of degummed Antheraea assamensis (muga) silk fibre

The paper discusses a special type of silk (muga silk) produced by the moth Antheraea assamensis (Lepidoptera: Saturniidae), which is available in the north east region, particularly in Assam, India. The structure of the degummed muga silk fibre is characterised by spectroscopy and X-ray diffraction. An attempt has been made to establish a correlation between the orientation of the protein of the fibre and the mechanical properties of the fibre. Inter-conversion of the - and -phases of proteins is very common, and in some cases, both the phases may be present. Since muga silk is a protein fibre, there is a strong possibility of exhibition of this inter-conversion property. The results show that the structure of muga fibre is made up of four molecular chains contained in a primitive tetrahedral cell with an average cell edge ao = b0 = 746 pm and c0 =738 pm (fibre axis) and lattice number 8. The space group of the -phase is P41, with screw axis 41. The -phase accounts for rigidity and crystallinity, while the -phase accounts for extensibility and the amorphous state of the fibre.