Evald L. Skau

Pore-Size Distribution in Textiles

THE APPLICATION of various permeability tests to textiles and textile materials has been a practice in the industry for a number of years, and the determinations of densities and total porosities have long been subjects of interest in this field. Sieminski and Hotte [13] ] have pointed out that the distinction between the terms porosity and pervvceability has not at all times been appreciated. Porosity of a textile fabric pertains to the total volume of void space contained within its boundaries, whereas permeability refers to the accessibility of the void space to the flow of a gas or a liquid. Porosity is usually defined as the ratio of the void space to the total volume encompassed by the boundaries of the material. Permeability is an empirical value, usually expressed as a rate of flow of some liquid or gas per unit area of fabric, and is a function of, among other variables, the differential pressure. These two properties of a fabric are thus quite different, and the relationship that exists between them is likely to be complex. The total porosity of a fabric can be visualized as

Simple Expressions for the Circularity and Fullness of Fibers

has been shown to bear a relation to many fiber properties and characteristics, such as maturity [2], luster [1, 4, 10], resilience [13~, mercerization [5, 6, 15], suitability for mercerization [10~, breaking strength [7], and dyeing qualities [9]. One of the difficulties involved in establishing definite correlations, however, has been the lack of a sound method of designating shape by means of a simple function which can be used as a numerical index.

Pore-Size Distribution in a Selected Series of Closely Woven Fabrics

The sorption on carbon black of a number of types of anionic, cationic, and nonionic surfaceactive compounds from aqueous solutions has been measured. It is shown that the sorption of these compounds does not conform to the Freundlich adsorption isotherm over the whole of the concentration range studied (0.01%—0.2% by weight). In the majority of cases an abrupt change in slope of the curve occurred at concentrations which appear to correspond, at least approximately, to the critical micelle concentrations of the various compounds. At concentrations above this critical point the plot of log X vs. log C appeared to be linear, but below the critical point considerable deviation from lineality was observed in some cases. The sorption of sodium alkyl sulfates increased with increasing chain length of the alkyl group at constant temperature, and decreased with increasing temperature at constant chain length. A series of compounds differing widely in chemical constitution, and including both anionic and cationic agents, were shown to be remarkably similar with respect to the general level of adsorption. Two typical nonionic compounds were found to be sorbed somewhat more strongly, particularly at higher concentrations, than any of the other compounds investigated. The addition of sodium sulfate to solutions of anionic compounds resulted in an increase in the sorption of the latter in every case. THE SORPTION of surface-active compounds by the soil and by fibers is believed to be an important factor in the complex mechanism of textile detergency [1, 8, 13, 14] . It is therefore of interest to obtain data relating to the sorption of a wide variety of detergent compounds, and in this connection measurements have been made of the sorption of various pure soaps from aqueous solutions by carbon black [9, 11 ] and by textile fibers [12]. The present paper presents similar data for the sorption by carbon black

A Comparison of Some Elastic Properties of Tire Cords

Additional information concerning the elastic properties of tire cords is needed since the present criteria involving breaking strength and elongation are considered insufficient to enable prediction of tire cord performance. The elastic behavior of Nylon, of rayon, and of unstretched and stretched cotton tire cords are compared with respect to their rates of elongation during measurement of the stress‐strain curves and their elongation under static loads at various temperatures between 25° and 200°C. Elongations under the influence of cyclic loads are shown for cotton and rayon cords, and an apparatus for determining mechanical hysteresis of tire cords during cyclic loading is described. The temperature and moisture content of the cord are shown to have considerable effect upon its elastic properties.