Poly (phenylene sulfide) (PPS) fiber (158 denier) was prepared by the melt spinning and thermal properties, such as phase transition temperatures, heat of transitions, were investigated by differential scanning calorimetry (DSC). In the DSC melting curve of the as-spun PPS fiber, the glass transition, cold crystallization and melting were observed. In order to investigate the enthalpy relaxation, PPS fibers were treated at a temperature lower than glass transition. The excess enthalpy was calculated from DSC curves of the annealed samples. Assuming the total excess enthalpy, ΔH0 of quenched sample could be calculated by the equation, ΔH0=ΔCp(Tg-Ta), where ΔCp is the heat capacity difference between the liquid state and the glassy state at the glass transition temperature (Tg) and Ta is the annealing temperature. From the change of the excess enthalpy with the annealing time, the relaxation time was obtained. It was found that the relaxation rate of PPS fiber was the highest among the reported values of other engineering plastics.
Poly (ethylene terephthalate) (PET) fabrics grafted with acrylic acid (AA) and methacrylic acid (MAA), especiálly its Na salt form, became hygroscopic. A wear comfortability under perspiration was expected from the view point of water transfer mechanism. A relative humidity change within a microspace between clothes and skin was thus evaluated by a model apparatus. AA/MAA grafted PET (Na salt form), PET, cotton and PET/cotton blend were used as sample cloths. As a result of the experiment, it became clear that with an increase in moisture absorbability of the sample cloths, a rising rate of relative humidity within the microspace became lower. The humidity change within the microspace under perspiration was presented by the following equation, where RH is a relative humidity (%) at time t (min.) and K is a rate constant. K value for each material changed in 2-3min, and the value in the first period was higher than that in the latter period.
The force required to thrust a hand sewing needle through fabrics for men's suites of various textures were measured employing the previously reported technique. The results were discussed in terms of the parameter of texture and of the physical properties measured by the method proposed by The Committee of Hand Evaluation. As the result, it was estimated that the force required for needle penetration was strongly affected by the volume fraction of fiber in the cloth and by the shear modulus. However, the other properties were estimated not to be essential to the force required for needle penetration. It was also ascertained that the force required for needle penetration was related to “Hari” and “Shari” of fabrics, but not to the other parameters estimated by KES hand evaluation. In addition, it was observed that, for the fabrics giving the smaller resistance to the needle, the better results were obtained in the shirring at the shoulder part of men's suites as well as in the evaluation of TAV, the total-appearance-value.
The geometrical patterns formed by superposing the two figures of dots arranged at points of intersection of rectangle fretwork have been investigated by using a personal computer. Rotating a dot plane (B-plane) to another fixed dot plane (A-plane), the rotation cycle at which the same patterns are formed is 180°, and the symmetric point is found at 90°. When the l2/l1-value is smaller than tan θ, the revealed patterns form rectangles which consist of dot chains surrounding overlapped dots, and the ratio of long to short side of the patterns is the same as that of dot pitchs, where θ is the rotation angle of B-plane to A-plane, l1 and l2 are the dot pitch of breadth and length, respectively. When the l2/l1-value is larger than tan θ, the patterns result in the drastic change which is not found in the case of the same two figures of dots arranged at points of intersection of square fretwork. These patterns will be expected to be practical as printing patterns for cloth etc.