Modification Of Wool Research Articles

Modification of Wool by the Application of Linear Synthetic Polyamides

Ethanolic potassium hydroxide solutions in concentrations from 0.1% to 5.0% have been used to pretreat wool effectively for the application of N-alkoxymethyl polyamides to prevent felting shrinkage. The alcoholic alkali may be used purely as a pretreatment, or the alkali can be incorporated in the alcoholic resin solution. Even when the alkali pretreatment does not in itself reduce the felting shrinkage, effective shrinkproofing is obtained with less than 1% resin based on the weight of wool.

Modification of Wool by the Application of Linear Synthetic Polyamides

N-alkoxymethyl polyamides may be applied to wool from aqueous dispersions containing a surface-active agent. If an anionic agent is used, the resin can be deposited on the wool by the addition of acid. For efficient deposition, the resin-detergent ratio must be chosen such that: (a) the net charge on the resin-detergent particles is opposite in sign to the charge on the fiber surface, and ( b) the amount of detergent is insufficient to interfere with the nonfelting action of the resin. Using a sodium secondary-alkyl sulfate as anionic detergent and a resin-detergent weight ratio of 20 :1, ethoxymethyl nylon has been applied to wool fabric from aqueous dispersions at approximately pH 2.5. The felting shrinkage of the fabric can be reduced appreciably by depositing about 6% resin on it in this way.

Modification of Wool by the Application of Linear Synthetic Polyamides

The presence of foreign materials such as soaps and oils on wool interferes with the deposi tion of N-alkoxymethyl polyamides when used for the prevention of felting shrinkage. If the wool is rigorously cleaned by ethanol extraction or if the fiber surface is modified by pretreatment with hydrogen peroxide or other reagent, then the resin is able to attain its maximum effect and approximately 3% resin (based on the weight of the wool) is sufficient to prevent felting shrinkage. It is suggested that both forms of pretreatment tend to improve adhesion between resin and fiber and so render the resin deposit more effective in preventing felting.

Modification of Wool by the Application of Linear Synthetic Polyamides

The effect of surface deposits of N-hydroxymethyl polyhexamethylene adipamide on the felting shrinkage of wool has been determined. These polymers resemble the N-methoxymethyl poly amides in that the polymer itself is not particularly effective in preventing felting shrinkage of wool, but when the substituted polymer is applied to wool fabric and then converted to the un substituted polyamide on the fabric, its effectiveness in reducing felting shrinkage is very much increased. A deposit of approximately 3% by weight of polymer on the fabric has been found to eliminate entirely felting shrinkage of the fabric under the test conditions. The optimum degree of sub stitution of the polyamide for production of non-feltability is similar to that found for the N- methoxymethyl derivatives— vi., between 20% and 25% -NH groups substituted. The N-hydroxymethyl polyamides can be converted to the unsubstituted polymers either by hydrolysis—e.g., with acids—or by heating in air.

Modification of Wool with Beta-Propiolactone

Modification of Wool with Beta-Propiolactone

The Chemical Modification of Wool—Treatment with Formaldehyde Solutions

A study was made of the reaction of formaldehyde with wool in order to determine optimal conditions for the production of wool that is more stable to alkali, as measured by the alkali- solubility test. Extremely mild treatments with dilute formaldehyde solutions confer an appre ciable degree of alkali-resistance to the wool, presumably by the formation of cross-links, and optimal alkali-resistance was obtained by treatment with 0.5% formaldehyde solutions at pH 6 to 8 for 6 hrs. at 50° C. Under these conditions, cystine linkages are not involved to any appre ciable extent, and the acid-combining capacity of the wool is changed only slightly. Although loss of sulfur from formaldehyde-treated wool occurs readily on treatment with hot alkaline solutions, the rate of loss of both sulfur and weight is less than in the case of untreated wool. The chemical evidence cited is in agreement with the view expressed elsewhere that additional cross-linkages are introduced in the wool molecule as a result of treatment with formaldehyde solutions. The lability of these new cross-linkages on exposure to acidic or hydrolytic condi tions is noted, and this behavior is compared with that of wool modified by other chemical reactions. Some comparisons are made with the use of the formaldehyde reaction in the regen erated protein-fiber field.

Modification of Wool by the Application of Linear Synthetic Polyamides

The effect of surface deposits of nylon and N-substituted nylons on the abrasion-resistance and felting shrinkage of wool has been determined. N-methoxymethyl nylons are much more effective than nylon itself, when applied from solution, in increasing the abrasion-resistance of wool fabric, but not in decreasing the felting shrinkage of the fabric. If the N-methoxymethyl nylon is first applied to the wool fabric from alcoholic solution and then hydrolyzed in situ by approximately 2N HCl, the polymer is found to confer non-felting properties on the wool. A deposit of approximately 3% by weight of polymer has been found to eliminate entirely the felting shrinkage of wool fabric under the conditions of test. The optimum degree of substitution of the nylon for the production of non-feltability is between 5% and 6% combined formaldehyde, which corresponds to between 20% and 24% —NH groups substituted. The effectiveness of these polymers in increasing abrasion-resistance and decreasing felting shrinkage is explained on the basis of their adhesion to and covering power on the wool fiber.

Modification of Wool by Rubber Latex

Modification of Wool by Rubber Latex

British Hat and Allied Feltmakers Research Association: Dr. Thomas Barr

Dr. Thomas Barr has been appointed director of research to the British Hat and Allied Feltmakers Research Association. This newly formed Research Association will carry out investigations on problems provided by members of the felt-hat industry. Initially, the work of the Association will be carried out in accommodation provided by the Textile Industries Department of the University of Leeds. The location of the new research group at Leeds should prove an attraction and stimulus, since for the past quarter of a century Leeds has been-one of the most active centres of both fundamental and applied research on animal fibres. Dr. Barr is at present in charge of a research section in the I.C.I. Dyestuffs Division, carrying out fundamental research work on textile processes involving the study of cellulose, natural and regenerated, the modification of wool and physiochemical studies of colloidal electrolytes such as synthetic detergents, etc.

Relation of Fiber Diameter to Modification of Wool Resulting from Chemical Processing

Relation of Fiber Diameter to Modification of Wool Resulting from Chemical Processing