Textile Research Journal

Four diepoxides, namely, the diglycidyl ether of 1,4-butanediol, meso-butadiene diepoxide, Eponite 100, and vinylcyclohexene dioxide have been applied to cotton print cloth (80 X 80) from methanolic and aqueous solutions in the presence of zinc fluoborate as catalyst. Physical properties imparted to cotton by these diepoxides under various conditions of reaction and cure have been evaluated. Data are presented to show varia tion of fabric properties with mole ratios of diepoxide: Zn(BF₄) ₂: AGU ( anhydroglucose units of cotton cellulose). It has been found for all except butadiene diepoxide that a given add-on does not result in like fabric properties and that for a certain percentage improvement in dry crease resistance, a higher retention in tensile properties is obtained at the higher AGU: Zn(BF₄)₂ mole ratio.

Shrinkage-time curves for a range of wool fabrics, and the effect of various shrink- proofing treatments on these curves, have been studied. Felting rates of untreated fabrics depend on fabric structure and applied force in the way previously established [e.g., 3, 13, 15]. The shrinkage-time curves of treated fabrics show two definite stages, an initial portion indicating a very low felting rate, followed by a second stage where felting may be much more rapid. For a given fabric structure and given applied force, the felting rates of both stages, and the times at which the second stage begins, depend on the degree of treatment. The two-stage curves indicate two distinct steps in the felting of the fabrics and are not due to the fibers being unevenly treated.

Frictional properties of treated Merino 64's fibers show no correlation with shrink resistance, and the results are qualitatively different from those found with Lincoln 36's.

The importance of defining washing conditions when testing shrink-resistant wool fabrics is again emphasized by results showing that quite different impressions can be gained by washing in different machines and thereby applying different mechanical forces to the fabrics. In an extreme case, a treated fabric of loose structure, when washed for a given time in two different machines, can appear to be either completely shrinkproofed or scarcely shrink-resistant at all.

In drying wool by forced air flow to a uniform regain in the range 8% to 16%, the amount of water removed per unit volume of air used is almost independent of the air temperature. , In view of this, the paper examines the practicability and economics of using unheated air for wool drying. Running costs depend on the atmospheric humidity , at the location of the dryer, but usually are appreciably lower than those of an efficient steam-heated dryer. The air intake per pound of water removed is much greater than in conventional dryers but the blower power required is approximately the same. No circulation is used, and this permits close control of the regain of the wool leaving the dryer.

Cotton samples with a wide range in fiber properties were chosen. An X-ray measure of the degree of crystallite orientation and/or the secant modulus of fifteen cottons are traced through levels from sub-fibers to single fibers to bundles to yarns. The differences due to sample characteristics gradually become less as the cottons progress through these levels. When the secant modulus of the yarns spun at the appropriate twist for maximum strength is referred to the X-ray measurement, no additional masking, but resolution occurs. The resolution seems to be more pronounced with American upland than with barbadense cottons. Tenacity, secant modulus, and bundle linear density primarily explain the rankings.

Kinetic studies of the sorption of water, following a change of water vapor pressure surrounding wool fibers and horsehair with a high initial or final water content, are described. The processes of absorption and desorption show non-Fickian behavior over the entire course of water content change. An additional non-Fickian anomaly, present for both integral and interval absorption, is an overshoot above the final equilibrium con centration of water in the fibers. It is apparent that the initial molecular configuration of the keratin has a marked influence on the sorption behavior. The effect is greater at the high relative humidities of the experiments reported in this paper than at intermediate relative humidities (approximately 50% RH) as reported in Part II.

Data obtained by a vibroscope technique show a different course of absorption, for the same changes of relative humidity around the fiber, than is found for the samples on the sorption balance. The non-Fickian nature of the process is evident in both techniques.

The effect of periodic acid oxidation on the wrinkle resistance of cotton fabric has been investigated. In the range of oxidation where basic fabric properties are pre served the dry WRA increases with increasing oxidation. The change in wet WRA for these fabrics is negligible, suggesting that cross-links which are evident in the dry state are broken in the presence of water. An explanation involving hémiacetal and hemialdal formation is advanced.

The constructional details and theory of operation of a highly stable and sensitive fiber and fabric friction sound analyzer are described. Sound pressure curves for three typical fabrics and one bulk wool are shown. Results will be described in detail in Part II.

A new technique for the differential staining of skin and core structure of nylon 6 and 66 yarn cross-sections has been developed. The technique requires the use of two water-soluble dyes, Kiton Pure Blue V, an acid dye, and Methyl Violet 2B Supra I, a basic dye. With these two dyes there is no chemical swelling of the cross-section as with ZnCl₂, iodine staining. Also the skin of an undrawn filament, which is reported by some investigators to be undetectable, can be stained.

Cotton cellulose dyed with direct cotton dyes was oxidized with buffered sodium hypochlorite solutions under different conditions. An attempt was made to correlate the extent of degradation of cellulose and the oxygen consumption during oxidation with the chemical constitution of dyes. The behavior of dyed samples during exposure to Fade-Ometer light has also been examined to study the influence of the constitution of the dyes. The results are discussed with a view to correlating the behavior of these dyes with that of leuco vat dyes under similar conditions.

The radiation-induced interaction of acrylonitrile with cyanoethylated cotton prob ably involves grafting of side chains of acrylonitrile at the site of the cyanoethyl groups. The extent of interaction is dependent on the degree of substitution of the cotton and on radiation dosage. There are increases in delayed elastic recovery and elongation- at-break and decreases in permanent set, average stiffness, and solubility of the cellulose of the treated cottons.