Robert M. Reinhardt

Preparation of Soluble Yarns by the Carboxymethylation of Cotton

Water- and alkali-soluble cotton fibers, yarns, and threads have been prepared by two methods. The cotton is preferably pretreated by pressure-kiering in 2% sodium hydroxide to remove the noncellulosic materials, and then treated with monochloroacetic acid and sodium hydroxide by either a one-step or a two-step process. Where only disintegration or partial solubility is required, the one-step method is sufficient. Where complete solubility of the cot ton is required, the process must be carried out in two steps: a mild, followed by a stronger treatment. The treated cotton is neutralized in alcohol with acetic acid to produce water soluble products or with strong acids in alcohol to produce water-insoluble but alkali-soluble products. Cotton in the form of sliver, yarn, and thread has been successfully treated.

Studies on the Partial Carboxymethylation of Cotton

Additional studies have been made on partial carboxymethylation—the reaction between mono chloroacetic acid and cotton in the presence of sodium hydroxide—and on the products ob tained. A thorough investigation of the time and temperature of reaction and concentration of reagents showed that relatively small amounts of monochloroacetic acid, properly applied, alter the properties of cotton considerably. Pilot-scale carboxymethylation of cloth was conducted which showed that it is possible to use standard textile machinery in the process. The cloth resulting from this treatment had a crisp liand with a slightly starched feel. More detailed investigations than reported previously were made, and it was found that the tensile strength and elongation of treated cotton are increased, dyeing properties are changed, and soiling-resistance and soil removal are increased. It was also learned that the treated materials are unaffected after one years storage.

The Preparation of Partially Cyanoethylated Cotton with Acrylonitrile

The preparation of partially cyanoethylated cotton with acrylonitrile in the presence of sodium hydroxide is described, including effects of changes in time, temperature, and concentration of reagents. Products with retention of the fibrous form have been ob tained with degrees of substitution up to 2.7 cyanoethyl groups per anhydroglucose unit. Hydrolysis of the cyanoethyl group occurs readily under alkaline conditions and re sults in both cleavage and conversion to the carboxyethyl group. Maximum conversion in the latter case was 29%.

Influence of Mercerization and Crosslinking of Cotton Fabrics on Dyeing Kinetics of Direct Dyes from Finite Baths

Dyeing of cotton fabrics treated with dimethyloldihydroxyethyleneurea and trieth anolamine is discussed. Adsorption time curves from finite baths of untreated, mer cerized, and crosslinked cotton print cloths have been studied. Mercerization did not change heterogeneous diffusion resistance but increased adsorption equilibrium con stants, dyeing affinities, and diffusion coefficients. Maximum dyeing capacities of mer cerized cotton were lower. Crosslinking reduced most of the kinetic constants (rate constants, structural diffusion resistance constants, maximum dyeing capacities, ac tivation energies, and diffusion coefficients). Triethanolamine additive enhanced the kinetic constants and the dyeabilities of crosslinked cotton fabrics. The results indicated that in the crosslinked cotton, triethanolamine reacted preferably with the crosslinks and not with the remaining free reactive groups of cotton fabric.

Crease-Resistant Cloth from Partially Carboxymethylated Cotton

A method of applying resin treatments to the acid form of partially carboxymethylated cot ton cloth to produce crease-resistance has been developed. The acidity of the carboxyl group and the higher swellability are advantageous for overcoming two difficulties met in the usual methods of producing crease-resistant cotton cloth by resin treatment. The presence of the acid carboxyl group supplies a built-in catalyst, making the addition of catalyst unnecessary, in this way avoiding the prepolymerization of resin baths which contain added catalysts. The high swellability of the modified cotton allows easier penetration of the resin-formers and larger pickup of resin, with the production of cloth of equivalent crease-resistance, of superior hand and abra sion-resistance, and better in most other physical properties, in comparison with the unmodified resin-treated cloth. The process of carboxymethylation, which consists of impregnating cotton cloth with a weak solution of monochloroacetic acid followed by treatment with strong sodium hydroxide, is com mercially feasible and can be carried out on ordinary textile equipment.

Studies on Permanent Creasing of Cotton Garments

the Southern Regional Research Laboratory has initiated work on the application of resin formulations to cotton garments for the express purpose of imparting permanent creases to them. In its full scope, the project has two phases: application to finished garments and application to yard goods, with resin curing in each case being accom plished on the finished garment. Advantages and disadyantages of the processes are described. Methods of application, procedures, and results are given for application of a dimethylol cyclic ethylene urea (CEU) formulation to swatches of fabric and to gar ments. Description is given of the effect of a numler of variables, such as the effect of storage on impregnated cloth, possibilities of stripping, precautions in drying and curing, durability to laundering, effect of sizing, effect of catalysts, and results using related resins in varying the formulation. Ultimate objectives are given including cooperative work with other research agencies to utilize standard drycleaning equipment for commercial application, use on yard goods, and development of non-chlorine-retentive finishes suitable for white goods in imparting permanent creases to cotton garments.

Part I: Purified Cotton:

β-Propiolactone was reacted with purified cotton in the presence of organic solvents. The reaction was found to be affected by time, temperature, and concentration of reagents. Weight gains of upwards of 60% were obtained. In all reactions of purified cotton with β-propiolactone in organic solvents, etherification oc curs, apparently followed by polyesterification of the attached groups by additional lactone. At tempts to direct the reaction towards either etherification or esterification by means of acid and base catalysis were not successful. Increases in the extent of reaction were obtained by activation of purified cotton with acetic acid prior to the treatments with β-propiolactone.

The Preparation of Water- and Alkali-Soluble Cotton Yarns

Reports in the public press have confused the two types of soluble yarns produced in the Southern Regional Research Laboratory. This letter differentiates between the alkali-soluble metal carboxymethylcellulose fibers previously described and the new water- or alkali-soluble modified cotton yarns. A typical method of preparation is described.

The Properties of Cotton Reacted with β-Propiolactone

A number of the textile and chemical properties of cotton reacted with β-propiolactone have been investigated and are reported. Differences in the properties of the products of the reflux and of the alkali methods of treatment are shown. Reaction of cotton with β-propiolactone yields a cellulose derivative with a bound graft polymer. The results of this unusual reaction are shown by optical means with micro scopic cross sections and electron micrographs, by changes in X-ray diffraction patterns, by influence on textile properties, by chemical effects such as saponification to yield car boxyethylcellulose, and by the production of unsaturation in the cellulose derivative.

Loss of Free Formaldehyde from Cotton Fabrics

Cotton fabrics with known free formaldehyde contents were prepared. Free form aldehyde contents of the fabrics were monitored after applying the formaldehyde and after subjecting samples to various experimental conditions that afforded opportunity for loss of the free formaldehyde. In this manner, it was possible to observe changes in formaldehyde contents from exposure of the fabrics to air, to water, and to other fabrics. The influence of time, temperature, moisture, and level of formaldehyde on these changes, and the effect of cellulose crosslinking were determined. The results are discussed with a view to enlarging and extending our fundamental understanding of formaldehyde release from finished cottons and, in particular, the role of free form aldehyde in the fabrics.