The puckering of polyester Yoryu crepe fabrics whose fillings were highly twisted and twist-set at various temperatures were observed in detail. It was ascertained that in the crepe fabrics the fillings take a spiral configuration the period of which corresponded to that of corugated puckers, and that z-twisted fillings were shaped like a z-spiral, while s-twisted fillings were like a s-spiral. The relation between the height and number of corugated puckers could be approximately represented by assuming a filling in the fabric as a cylindrical spiral. The spiral configuration was assumed due to the tortional buckling that was caused by the torque released in the fillings when the fabric was scoured. A model to represent the puckering mechanism was presented extending the Hearle-Yegin model for cylindrical snarling to take account of the effective energy due to the shear of a fabric. The relation between the height and period of corugated puckers was derived based on the model, which could reproduce well the experimental results. The critical torque of pucker formation was evaluated by the model, which had a linear relation with the residual torque in the twist-set fillings before scouring.
The anionic graft polymerization of vinyl monomers on epoxy-activated cellulose (CGE) was carried out in the presence of tertiary amine in dimethyl sulfoxide. The polymerizability of the monomers was in the order, methyl vinyl ketone (MVK)>acrylonitrile (AN)>methacrylonitrile (MAN)>methyl methacrylate (MMA), when the polymerization was carried out with triethylenediamine (TEM)/butyl glycidyl ether complex as an initiator. MVK and AN were successfully polymerized by TEM/CGE complex leading to the formation of graft celluloses, whereas MAN and MMA were not polymerized, because of the low oxirane content of CGE. For the graft polymerization of MVK and AN on the cellulose, TEM was the most suitable tertiary amine among the amines tried for the preparation of graft cellulose with higher grafting. The highest grafting was obtained by the use of equimolar amounts of TEM and oxirane. The grafting remarkably increased with the increase in the dielectric constant of the solvent used and the monomer concentration. The effect of reaction temperature on the grafting was small, and the apparent activation energy of the polymerization of MVK and AN were 35.9 and 9.2kJ/mol, respectively.
Cellophane was dyed with methyl orange (MO), ethyl orange (EO), and butyl orange (BO) in the presence and absence of sodium chloride. The resultant adsorption behaviors of MO and its homologs on the cellophane were interpreted on the basis of a mean activity coefficient and an aggregation number of the dye which were reported in previous pubulications. In the absence of NaCl the amounts of the dyes taken up by cellophane at 50°C were in the order MO>EO>BO. According to the previous reports, the dye aggregates in aqueous solution and the aggregation number increases with an increase in the carbon number of alkyl groups in the dye molecule. Consequently, with increasing aggregation number the repulsion forces between the negatively charged cellophane and dye increased and the diffusivity of the dye into cellophane was slowed down. Thus the amount of the dye taken up by cellophane decreased. The chemical potential of the dye in aqueous solution obtained from the previously reported activity also suggested that the tendency of the dye to transfer from the solution to the matrix lowered with increasing carbon number of the alkyl groups. Dye disaggregation caused by raising temperature of the solution resulted in the increase in the adsorption of BO at higher temperatures. The dye adsorption in the presence of 0.03M NaCl can be also explained on the basis of dye aggregation.
The flow resistance of a clothed human body exposed to a strong wind (5-30m/s) was studied using a model system; a cylinder being loosely wrapped with a cloth. The drag coefficient of wind CD increased with increase in the Reynolds number Re, when the cylinder covered by an endless cloth was exposed to wind. The value CD tends to converge when Re approaches about 1.0×105. If the length of the cloth was less than twice the cylinder perimeter, the cloth shape in the wake of the cylinder was changed into beam-, ellipse-, or stable heart-, like shake, but CD converged to the same value for almost all cases. The converged value, however, increased when the length of the cloth was near triple the perimeter of the cylinder. This value was found not to depend on the roughness of fabric surface and on the bending stiffness, but to depend only on the length of the sample cloth. The sample cloths of large air permeability and smooth surface showed almost similar CD values for any sample length.
The bending deformation of clothes acting on a lateral load and compressive load were discussed by means of “The simulation used with an area moment method” which were suggested in the previous paper. The authors proposed a new simulation method to calculate the deflection curve of the beam with simply supported ends to which lateral load and compressive load were added. By this method, it was proved that the deflection curve of the beam could be calculated with high accuracy. Especially, it was proved that the deflection values could be calculated when the compressive axial load larger than critical load of buckling was added to the beam.
An instrument to measure the force developed during needle penetration through fabrics was proposed. From the stage of sample setting until completion of a measurement, the entire process is automated and it is possible to observe the portion where a needle enters a fabric texture by employing fiber optics. The relationship among the specific forces along the recorded force line, the kind of the fabric and the mode of needle penetration were examined. By using this instrument, it is possible to investigate the properties of a fabric related to needle penetration including the properties of a limitted portion of the fabric and effects of various fabric treatments.
Merino wool fibers were treated with neutral protase which is a kind of enzyme to decompose protein. The surface structure of the fibers was observed using a scanning electron microscope. Weight loss by the treatment and the influence of the treatment on dyeing with acid dyes were also investigated. Although the fibers received almost no damage by the treatment in short time and weight loss was negligibly small, rate of dyeing was increased by the treatment. From these results, it seemed likely that the structural relaxation of interscale micellar substance facilitated the dye penetration into the fibers.