Textile Research Journal

Optimum quality from cotton at the textile mill depends on the need for improvements in a number of handling areas. Processing and yarn quality problems sometimes occur through overdrying practices. Excessive heating of cotton causes discoloration (yellowing), reductions in strength, and increased fiber breakage. The severity of damage increases as exposure time and temperature increase. Chemical and physical tests were conducted on heated cottons of high, medium, and low Micronaires to determine changes that may affect cotton processability and overall quality. Mechanical processing of cotton immediately after heating (at reduced moisture levels) had a greater adverse effect on physical fiber properties than did mechanical processing after heating and allowing time for moisture regain. Compared to yarn from unheated cottons, yarns from heated cottons had increased levels of neps and reduced strength and uniformity.

Characteristics of air-jet textured yarns are determined by the instability, linear density, and strength, together with structural properties such as loop size, loop frequency, and degree of entanglement. Such characteristics are affected by various process parameters and supply yarn properties. The effects of these parameters on the final yarn properties have been investigated using instability, linear density, and strength tests, together with SEM photographs for visual assessment of the yarn structure. Optimizing any given yarn property almost always affects other yarn characteristics, and therefore this must be remembered when selecting suitable process parameters and supply yarns for specific end uses. For a given texturing nozzle and conditions, there is an optimum filament fineness and number of filaments that can be textured effectively.

The fundamental data required to establish the technique of dyeing nylon and wool fibers in a water/perchloroethylene dye bath were gathered. A sodium atom of CI acid blue 62 was substituted by a series of normal alkylamine and hydrogen atoms in order to obtain complex dyes that are soluble in perchloroethylene. These dyes, which have 6, 9, and 12 carbon chain lengths, have good solubility in both water and perchloroethylene. This can be attributed to the fact that these dyes are dissolved in a dissociated state in water and in an undissociated state in perchloroethylene. The saturated amounts of these complex dyes on nylon 6 films dyed in each bath were greater than those of the original dye. There were differences between shades of nylon 6 films dyed in water and in perchloroethylene, and these seem to be attributable to the different degrees of aggregation of the complex dyes.

The electrostatic propensity of carpets, as measured by a stroll test, has been compared with both the bulk and surface resistances of the carpets measured under the same atmospheric conditions. The correlations between electrostatic propensity and electrical resistance were poor for both the bulk resistance and surface resistance cases. In spite of the poor correlations, it would appear that the 2 times 10¹⁰ ohms recommendation presently in vogue will guarantee that the electrostatic propensity of the carpets should be less than the threshold of shock perception.

The presence of glycolipids on wool fibers has been detected by analyzing the solubilized material when wool is treated with different organic solvents selected to remove internal lipids. One of these has been isolated and identified as a glucosilceramide. These compounds are thought to contribute to the bilayer structure that may be present in the β-layers of the cell membrane complex.

The contribution of the three different splice elements was studied. Splice strength is primarily due to intermingling/tucking. Twisting also contributes significantly to splice strength, but the contribution of wrapping to strength is minimal.

The equilibrium sorption of ten cationic dyes by porous and regular acrylic fibers has been investigated. The data have been interpreted by a simple Donnan approach, based on the assumption that there are two different types of acidic groups in these fibers. The ionic distribution coefficients K_D for the dyes and the fibers were calculated. These coefficients provide an indirect measure of the “affinity” of the dyes for the fibers. The values of K_D have been discussed in relation to the structures of the dyes and fibers, and in relation to the effects of salts, pH, and temperature.

Fabrics made from friction spun fillings (friction fabrics) had a hand that was judged to be equivalent to fabrics made from ring spun fillings of the same count (ring fabrics). Fabrics with rotor spun fillings (rotor fabrics) had a hand that was harsher than either of the others. The friction spun fillings only had a tenacity of about 57% of ring yarns. Plain weave friction fabrics had a tenacity in the filling direction of about 70% of ring fabrics and 66% for twill weave fabrics. The tear strength was 63% of the ring fabric. Warps were common in each set, but the substitution of one filling by another type altered the fabric performance in the warp direction even though the filling yarn count was unchanged. The topography of the fabric surface was changed by the substitution. Harmonic analysis of surface roughness data showed the effects to be considerable. Fabric bending stiffnesses changed by altering the fabric and yarn structures, but the two methods of measurement did not give identical assessments of these differences. Fabric shear and hysteresis losses suggest that friction fabric might tend to “bag.”

Recently green motes have formed in fabrics made of Pima cotton. The green color is resistant to normal bleaching with chlorite, hydrogen peroxide, and hypochlorite. The pigment may be destroyed by a combined bleaching process, usually hypochlorite-hydrogen peroxide. The whiteness obtained with this process is similar to that of normal fibers.

An analysis of the data for a classical expression of loop shape factor reveals the inadequacy of this parameter in representing loop shape. A modified loop shape factor has been proposed and appears to express the three-dimensional loop shape more closely. The loop shape of cotton yarns at the fully relaxed state is not unique. The stability and stabilization process of loop shape have been investigated, pointing to the need for a more fundamental approach.