The high-speed spinning of poly (ethylene terephthalate) has been carried out for take-up velocity up to 10000m/min in order to investigate necking behavior. Fiber diameter and temperature were measured along the spinline by optical methods, and spinning stress was measured after the end of thinning process. Strain rate, spinning stress and elongational viscosity were estimated from the measured data. The reduction of elongational viscosity is observed at a point where the fiber diameter is rapidly reduced, though the fiber temperature is decreased monotonously. This reduction of viscosity assigned to the onset of necking. In the case of take-up velocity of 10000 m/min, the necking begins at the fiber velocity of 288m/min at 221°C. This suggests that the necking occurs in the molten state for the ultra-high speed spinning. The necking begins at lower fiber velocity, lower stress, lower elongational viscosity and higher fiber temperature with increasing take-up velocity. This indicates that the necking is determined by the different kinds of forces along the spinline, such as spinning stress and cohesive force.
The experimental study on melt spinning has been carried out for a petroleum mesophase pitch. The thermal properties were examined by thermogravity analysis and dilatometric measurements. Glass transition temperature of the mesophase pitch is 130°C which is higher than that of isotropic petroleum pitches. A die swell can not clearly recognized in the mesophase pitch melt spinning. The strain rate of the running filaments is extremely high by comparison with polymer melt spinning; the value is attained to 150sec-1 at the maximum point along the spinline. The region of elongational deformation is very narrow and close to the spinneret. The elongational viscosity of the deformation region is the range from 3×103 poise to l×104 poise, which is similar to that of the conventional polymer melt spinning. The temperature at solidified point of the running filaments is 270°C, The mesophase pitch orients even by shear flow in a capillary die and the orientation of methophase pitch further increases by the elongational flow of running filaments along the spinline.
In this paper, using the technique of information theory, how the information of sight and touch stimuli was changed into the panel's response information by the biological information processing system was discussed when the sensory values of pile fabrics were evaluated by the panel's senses of sight and touch. The results obtained are as follows; (1) When the sensory values of pile fabrics were evaluated by the consumers' and specialists' senses of sight and touch, the sight (or touch) information added to the touch (or sight) information was recognized as the sensory values by both groups. (2) When consumers evaluated the sensory values of pile fabrics using the information of sight and touch stimuli, the ratio of the touch information to the sight and touch information was about 31_??_36% and the ratio of the sight information was about 65_??_71%. On the other hand, the ratio of the touch information was about 46_??_49% and the ratio of the sight information was about 52_??_56% on specialists. In view of these facts, it was found that consumers depended on the sight information more than specialists in evaluating the sensory values of pile fabrics. (3) Relations among_??_st, _??_t and_??_s, is expressed in the following equation (1). (1) where_??_st, _??_t and_??_s are mean preference values evaluated by the senses of sight and touch, the sense of touch, and the sense of sight, and A and B are constants. And there is a good agreement between measured mean preference values and values calculated by Eq. (1). (4) It was found that the visual and tactual sense values were determined by fitting Eqs. (1)_??_(17) using the physical properties and the three attributes of color perception (hue, value and chroma) of pile fabrics and the obtained data agreed well with the sensory values evaluated by consumers' and specialists' senses of sight and touch.
The modification of silk fiber by freezing-drying after immersion of silk fiber in water is a process of bulkiness modification, in which the volume expansion of water due to freezing was utilized. In this paper we intended to elucidate the conditions for swelling and freeze-drying and to clarify the relation between the structure and the mechanical properties of silk fiber. The rapid freezing of silk fiber was required for the prevention of fiber degradation. From the morphological observation, silk fibers were expanded by freezing of water in the viods and crackes. Therefore, the bulkiness, softness and hygroscopic property of silk fiber were improved by the freeze-drying. The crystallinity was unchanged by the freeze-drying, however, the changes of microstructure related to the mechanical properties of silk fiber.
In order to investigate the effects of the ribs of fabric surface on water repellency, the relation between the diameter 2r and distance 2(r+d) of parallel lining nylon filaments at equal intervals and water repellency was obtained from the sliding angle of water droplets. Sliding angle was affected by the diameter and distance of filaments, and there was a tendency that the water repellency increased when r became small and r+d became large. When (r+d)/r is over 3, water repellency is excellent. Cassie and Baxter showed that the water repellency was greatly affected by the surface structure, especially the proportion of the liquid/air interface to the surface area determined the water repellency. Based on the above results, Cassie and Baster's theory was confirmed to the wide range cylindrical samples by the sliding angle of water droplets.