FIBER STRUCTURE AND TENSILE ROPERTY OF CHITOSAN FIBER SPUN FROM LYOTROPIC LIQUID CRYSTALLINE SOLUTION

A spinning system to produce chitosan fibers from lyotropic liquid crystalline solutions was designed. The fine structure of the chitosan fiber was investigated by using polarization microscopy and X-ray diffractometry. Tensile properties were also examined. The chitosan fiber showed a so-called “banded structure” similar to those previously found in the Kevlar fibers and chitosan films prepared from similar liquid crystalline solutions under shear deformation. The X-ray diffraction pattern showed two strong and sharp spots on the equator. These facts indicated that molecular chains in both amorphous and crystalline regions were highly oriented along the fiber axis. Such a structure is expected to give high performances of chitosan fibers. This fiber actually showed several fold increases in the modulus and breaking strength from fibers prepared by conventional wet spinning. It was concluded that the liquid crystalline spinning was effective for obtaining high-modulus and high-strength chitosan fibers.