Herman Bogaty

Water Transport Mechanisms in Textile Materials1 Part I: The Role of Yarn Roughness in Capillary-Type Penetration

The movement of liquid water in fiber assemblies such as yarns and fabrics is examined in terms of a theory of water transport based on a capillary penetration mechanism. Yarn construction features, such as twist, diameter, crimp, and fiber denier, are shown to be related to the rate of water transport in such fiber assemblies. From measure ments of yarn and fiber water contact angles, it is shown that water transport in yarns is only slightly influenced by the wetting properties of the individual fiber materials and depends mainly on the wetting behavior of the whole yarn. Increase in yarn roughness due to random arrangement of its fibers gives rise to a decrease in the rate of water transport, and this is seen to depend on two factors directly related to water transfer by a capillary process. (1) The effective advancing contact angle of water on the yarn is increased as yarn roughness is increased. (2) The continuity of capillaries formed by the fibers of the yarn is seen to decrease as fiber arrangement becomes more random. The measurement of water transport rates in yarns is thus seen to be a sensitive measure of the properties of fiber arrangement and yarn roughness in textile assemblies. The present studies on cotton, nylon, Dacron, wool, and wool blended yarns thus indicate that an appropriate choice in fiber crimp, fiber denier, yarn size, and blend uniformity are all important in obtaining blended fabrics of desired properties.

Some Thermal Properties of Fabrics Part I: The Effect of Fiber Arrangement

Examination of the thermal conductivity of fabrics in terms of the fiber conductance and fabric density shows that fabric insulation is determined by fiber arrangement as well as by fabric thicknes. Fiber arrangement is interpreted in terms of fibers lying parallel and perpendicular to the fabric surface, and it is shown that fabrics differ appreciably in this respect. For the smooth surfaced fabrics of cotton, nylon, and Orlon studied, the in crease in specific conductivity with applied pressure can be attributed mainly to an in crease in fabric density as there is very little change in fiber arrangement in such fabrics. For fuzzy surfaced fabrics of wool or blends containing wool, the change in density with applied pressure is counterbalanced by changes in the fiber arrangement. At low pres sures a substantial portion of the fibers lie perpendicular to the fabric surface but are bent over as the pressure is increased. At high pressures the fibers lie mamly parallel to the surface, but the fabric conducts less effectively because of the air layers between each fiber along the conducting path. Accordingly the specific conductivity of wool and wool-type fabrics is relatively insensitive to changes in applied pressure and this appears to be a direct result of the random arrangement of the fibers in these fabrics.

The Nature of a Fabric Surface: Thickness-Pressure Relationships

A STUDY of fabrics made of synthetic fibers and of blends of various synthetics with wool is now in progress in these laboratories. Work on some phases of this program has reaffirmed the importance of the surface character in the tactile impressions of a fabric as well as in many aspects of service behavior. The surface fuzz, furthermore, may contribute substantially to the over-all thickness of a fabric, and thus plays a part in functional properties, such as warmth [2, 4]. For these reasons, attention was directed to the determination of the thickness of fabrics at various

A Simple Quantitative Test for the Felting of Wool Top

A simple, rapid procedure for evaluating the feltability of wool in the form of top is pre sented. The method consists of subjecting a sliver to controlled wet mechanical action, and measuring its change in length. It yields results which correlate well with the shrinkage during laundering of garments made from the top; the method thus provides a useful tool for con trolling the application of some chemical shrink-resistant treatments in the mill. In addition, this method shows promise of usefulness as a tool for investigating the nature of felting.

Some Observations on the Evaporation of Water from Cellulose

The influence of water on the deterioration of cellulose is discussed, with special reference to deterioration at the brown line which forms when water rises in cotton by capillary action. The brown, fluorescent, water-soluble material results from the evaporation of water at the cellulose-water-air interface. Oxycellulose of the mildly reducing acidic type is formed. The oxidation appears to occur in part at the primary hydroxyl group, with the formation of polyglu curonic acid followed by chain scission and formation of soluble, low-molecular-weight frac tions. The deterioration proceeds even at moderate temperatures and in diffused light indoors. The brown-line effect undoubtedly contributes significantly to the degradation of cotton during its production, processing, and use.

Structural Compactness of Woven Wool Fabrics and Their Behavior in Modern Washing Machines

A wide array of commercial all-wool fabrics have been subjected to physical analysis and to ten consecutive mild launderings in a modern automatic home washing machine. Many of the fabrics are shown to exhibit low levels of shrinkage in this test. The shrink age of the fabrics of the same weave type is shown to be related to the cover factor of the cloth. A measure of compactness of fabric structure can be computed from the ratio of observed cover factor to the theoretically maximum weavable cover factor. This compact ness ratio shows a good functional relationship to shrinkage in laundering for virtually all of the fabrics. irrespective of weave. This relationship indicates that a commercially acceptable fabric may be designed with respect to its compactness to give low levels of feltability in many repeated launderings.

Some Properties of Serges Made from Blends of Wool with Acrylic Type Synthetics

The introduction of many types of new fibers in the past decade has increased the variety of possible combinations in blending to a very high degree. The traditional sequence in evaluation of fabrics involving the steps of fabric design, preparation, and testing now has become increasingly slow and expensive. This has led to an appreciation for the need of better organized approaches to develop the basic principles needed to relate the behavior of the fabric to the

Some Thermal Properties of Fabrics

Examination of the thermal conductivity of fabrics in terms of the fiber conductance and fabric density shows that fabric insulation is determined by fiber arrangement as well as by fabric thicknes. Fiber arrangement is interpreted in terms of fibers lying parallel and perpendicular to the fabric surface, and it is shown that fabrics differ appreciably in this respect. For the smooth surfaced fabrics of cotton, nylon, and Orlon studied, the in crease in specific conductivity with applied pressure can be attributed mainly to an in crease in fabric density as there is very little change in fiber arrangement in such fabrics. For fuzzy surfaced fabrics of wool or blends containing wool, the change in density with applied pressure is counterbalanced by changes in the fiber arrangement. At low pres sures a substantial portion of the fibers lie perpendicular to the fabric surface but are bent over as the pressure is increased. At high pressures the fibers lie mamly parallel to the surface, but the fabric conduct...

The Felting of Shrink-Resistant Wool as Related to Some Properties of the Single Fiber

the work of extension, and a and b are constants. This equation was found to hold for untreated wool tops in a wide variety of reagents. The extent of shrinkage of wool which has been subjected to a chemical antifelting treatment would also be expected to be influenced by the nature of the felting medium, depending upon the extent to which the wool has been modified in processing. Much of the study of fiber properties in relation to the feltability of shrinkresistant wool has heretofore emphasized the importance of the surface of the fiber. Thus, it has been clearly established that chemical treatments for conferring shrink-resistance to wool which involve the use of active chlorine result in a decrease in the direc-

The Nature of a Fabric Surface: Evaluation by a Rate-of -Cooling Method

Certain proteins and other polymeric materials have been found highly effective in preventing the redeposition of carbon black, a test soil, on cotton fabric in aqueous cleaning systems containing an alkylarylsulfonate detergent and alkaline builders. The soil-redeposition-preventing properties of the various proteins tested were found to be correlated approximately with their proline content. The proline-rich proteins gave good to excellent whiteness retention. Of several synthetic polymer materials investigated, the uncharged types were more effective than the charged types. For the uncharged polymers, polyvinylpyrrolidone, polyvinyl alcohol, and polyethylene glycol, an optimum degree of polymerization was observed for maximum effectiveness. IN any textile cleaning operation the ability of a detergent system to prevent soil from redepositing on the fabric after it has once been removed is of equal importance to its ability to remove soil initially. Investigators have referred to this phenomenon variously as &dquo;soil redeposition,&dquo; &dquo;soil suspension,&dquo; or &dquo;whiteness retention.&dquo; The highly effective action of certain proteins and synthetic polymeric materials in preventing the deposition of carbon black from an aqueous alkaline-built alkylarylsulfonate detergent solution is described in this report. The importance of soil redeposition as a factor in detergent action was first stressed by Carter [ 5 ~ , who reported that the silicates and phosphates prevented redeposition much more effectively than sodium hydroxide or sodium carbonate when used as builders for soap. This finding was confirmed by Powney and Noad [9] and by Vaughan and Vittone [ 11 ] . In recent years the problem of preventing soil redeposition has assumed additional importance because of the relatively poor whiteness retention associated with the use of synthetic detergents in comparison with soap. This point is well illustrated by the recent work of Wagg [12], who showed that sodium oleate is superior to four representative types of synthetic detergents in the prevention of soil redeposition. As in the case of soap, the silicates and phosphates have been reported to be effective in improving the whiteness retention of alkylarylsulfonate detergents [7]. A generally accepted postwar innovation for improving whiteness retention is the use of sodium carboxymethyl cellulose (CMC), a German World War * This work was supported by a Working Fund provided by the Quartermaster Corps, Department of the Army. This report was presented at the 123rd National Meeting of the American Chemical Society, Los Angeles, Calif., Mar. 1953. A report based on this paper appeared in the Sept., 1953, issue of Industrial and Engineering Che1llistr:y. t Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture. ’