Studies on micro structure of cotton fiber - Relation between micro-fiber structure and bulkiness of the wad

The purpose of this study was to clarify the micro-structural effect of cotton fiber on the bulkiness and softness of a cotton wad. The micro-fibril orientation at the surface of a cotton fiber was analyzed by a fluorescence polarization method using a polarizing microscope. The convolution length (convolution period) of a cotton fiber was measured under a microscope. The bulkiness and softness of the cotton wad were analyzed by measuring the specific volume change using a structure stabilization method by vibration under various loads. The results showed that the larger the orientation angle of the fibrils in a cotton fiber is, the shorter its convolution period becomes. This means that a cotton wad having fibers with a shorter convolution period has more bulkiness and softness. We concluded that the helicoidal orientation of the fibrils not only makes the convolution of cotton fibers complex but also influences the physical properties of the wad.