Tensile Properties
The fineness, tensile properties and moisture regain of the silk fibers from the three layers of A. atlas cocoons are compared with that of B. mori and two common wild silks in Table 2. As seen from the table, fibers from the outer layer of A. atlas cocoons are coarser than the fibers from the intermediate and inner layer. However, the A. atlas silk fibers from all the three layers are coarser than B. mori silk fibers but much finer than A. mylitta and P. ricini silk fibers. Although the inner layer of A. atlas co- coons contains the finest fibers, the breaking tenacity of the fibers in the inner layers (3.6 g/den) was lower than the fibers in the outer and fiber layer. The breaking te- nacity of the fibers from the outer and intermediate