Chemical Processing: Key to Tailor-Made Cotton Fibers - Chemical

Nov 5, 2010 - "In five to 10 years, fabrics entirely unknown today are expected to be important items in the consumer's wardrobe, as well as in househ...
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dangerous substances for which the symbols should be employed. Representative Meeting. Each country taking part in the chemical industries committee meeting was allowed two representatives each from government, labor, and management. United States representatives, in addition to those mentioned, were: Robert Barnett, American Legation at Bern; Henry Johnstone, Merck; and Joseph Joy, United Gas, Coke, and Chemical Workers, CIO. W. P. Gage, Shell Chemical, was an alternate delegate, and Philip Singleton, Monsanto, an adviser. In all full working parties and subcommittees there were representations from each of the three branches concerned. Points of view ranged from the strongly conservative to the strongly opposite views from the Communist labor representatives, of which at least two were present. Relatively little vitriolic argument came onto the floor of the plenary sessions, except, for example, when a British labor representative scored the French Communist with a direct opinion of the latter's failing to uphold agreements made in committee meetings. Two resolutions, presented by the representative of the Italian Communist union, referring to "peace," commercial exchanges among all nations regardless of social or economic systems, and refusal to help produce bacteriological weapons, were considered by the steering committee to be outside the scope of the chemical industries committee's prerogatives. This opinion* was upheld by a vote in plenary session with only two delegates opposed. Health Measures and Working Hours. The interest in safety and health measures was very high during this meeting, noted John Price, head of the industrial committees division of the ILO, in addressing the final session, and there has been extended discussion of hours of work. While these were not on the agenda for formal consideration at this time, he said, it is likely that they may be on the agenda of the next meeting of the chemical industries committee. Mr. Price commented also that there had been a great deal of interest in industrial relations, which seemed to be another likely prospect for consideration by the next meeting. Mr. Price called attention to the fact that the decisions of the ILO are not binding on the countries which are its members, but rather their value depends on the use which is made of them in those and other countries. Comments from the organizations concerned are eagerlv sought by the ILO. Resolutions offered by the steering eomimittee and passed in plenary session, recommended that the agenda for the Inext meeting of the chemical industries committee include consideration of improvements in productivity obtained from systems of payment by results and from echniques concerned with their application; problems arising and measures to be aken in regard to safety and hygiene; industrial relations; and the reduction of hours of work in the chemical industries.

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C&EN REPORTS: National Cotton Council of America Conference

Chemical Processing: Key to Tailor-Made Cotton Fibers Industry seeks to improve cotton fibers through fundamental and applied studies WASHINGTON, D. C.-Virtually unlimited opportunities to produce new fibers and new textile materials from cotton are offered by chemical finishing, C. H. Fisher, U. S. Department of Agriculture, advised members of the National Cotton Council at their two-day conference held here Sept. 25 to 26. As part of a concerted effort to develop new and better fibers and textiles from cotton, the council sponsored its first technical symposium on the subject of chemical finishing. About 90 of the nation's leading textile scientists attended the meeting. "In five to 10 years, fabrics entirely unknown today are expected to be important items in the consumer's wardrobe, as well as in household and industrial uses," Leonard Smith, director of utilization research for the council stated. "Chemical finishing is the relatively young science from which amazingly different cotton fabrics are expected to develop. Already chemists have been able to combine chemicals with cotton to yield fabrics resistant to heat, wrinkles, stains, and mildew, and in the laboratories, even greater progress is indicated." Chemical Treating. Chemical finishing, Dr. Fisher stated, involves a chemical treatment of cotton which alters the composition and structure of the cellulose molecules without destroying the fibrous form. The resulting fibers are new compositions with chemical and physical properties entirely different from the original cotton. Esterification and etherification are two methods which have received the most attention. Production of tailor made fibers for definite end uses from cotton include carboxymethylation, chemical bonding with resins, and treatment with octadecyl isoeyanate, J. David Reid, USDA, reported. Each of these treatments represents an entirely different approach. Carboxymethylation, for example, results in a deep seated change in the cellulose molecule in which each carboxymethyl group added is attached to a hydrcxyl group and distributed fairly well throughout the fiber. Carboxymethylation yields a permanently "starched," highly absorbent product. The product is susceptible to treatment with usual, conventional creaseproofing resins, resulting in superior creaseproof properties without unusual stiffness. Hesin-forming chemicals, such as

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/3-propiolactone, not only bond chemically with the cellulose but may react further with the group so attached to yield a resinlike material bonded chemically to the cellulose. The resulting products have reduced water-absorbency, a large increase in fiber bulk and diameter, and resistance to some types of acid degradation. Little or no loss in breaking strength is involved. Possible uses include fibers for rugs and carpets, electrical insulation, and soil-resistant textiles. Surface Reaction. Another chemical method of modifying cotton is a topochemical or surface reaction type. The use of octadecyl isocyanate to give a water repellant textile is typical. Because the isocyanate molecules are large, they do not penetrate the fiber wall and therefore small amounts are sufficient to cover the surface of the fiber. Most conventional finishing processes, which are designed to enhance the feel (hand) and appearance of the fiber or textile, do not impart new qualities such as added durability, C. Norris Rabold, of Erwin Mills stated. The newer chemical finishes are used not only to improve durability but also to impart specific properties for particular uses. Wrinkle resistance in cellulose fiber materials may be achieved by using chemical fibers which inhibit fiber swelling, R. F. Nickerson, Monsanto Chemical Co., reported. The process involves placing dry cellulose in an aqueous solution of the reactant and a catalyst. As the fibers swell, the reagent and catalyst are carried into the fiber, where they are deposited. Drying and heat treatment complete the process. Reactants generally consist of polyfunctional compounds of the methylol type related to hemiacetals. Partial Conversion. The partial acetylation of cotton resulting in partial conversion of the cellulose to cellulose acetate may be accomplished at a modéra ve cost, Edward M. Buras, U. S. Department of Agriculture, reported. The cost is more than offset by the greatly improved service life and potential applications where rot or mildew and heat resistance are important factors. Aminization of cotton fibers is possible using 2-aminoethylsulfuric acid, John D. Guthrie, USDA, reported. The arninized cotton takes on most dyes more readily than ordinary cotton. Of interest is the fart that uininizntion serves as a means of introducing other groups to cot4153

THE CHEMICAL WORLD THIS WEEK

mût TRADE-MARK

ACETONITRILE NiACET Acetonitrile is

α

stable,

c l e a r , colorless l i q u i d w i t h aromatic odor. It has a

an

boiling

range of 8 0 to 82°C. / a purity of 9 9 . 0 % minimum, and a specific gravity

of

0.782

to 0.785

at

20°C REACTION

MEDIUM

Acetonitrile is used as a reac­ tion medium f o r

reactions

pro­

Raw-stock processing, yarn treatment, batch and continuous piece goods finishing were the topics considered in a discussion led by George Buck of the Utilization Research Division. Seated on t h e platform is Sydney M. Cone, Jr., president of the association

ceeding under ionic mechanisms. It has a high dielectric constant and is an excellent solvent f o r a w i d e variety of compounds. Some c o m p o u n d s which d i s s o c i a t e in water

can be

successfully

dis­

solved in Acetonitrile.

PURIFICATION Acetonitrile is a medium for the purification of compounds by recrystallization. The solubility

of

many compounds is affected by comparatively

small changes in

temperature, so that a saturated solution

precipitates

the

solute

r e a d i l y in cooling. The volatility of Acetonitrile is an a d d e d a d v a n ­ t a g e as all traces can b e removed readily. For further

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Carbide and Carbon Chemicals Company A Division of Union Carbide and Carbon Corporation

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4154

ton, including those which give flame re­ sistance, rot résistai ice, water repellency, and cation exchange materials. Treatment of cotton with cthylamine is considered to he a satisfactory method ot reducing the unfavorable crystallinity of cotton cellulose. Carl Conrad, USDA. stated. The cthylamine treatment, he said, may be carried out commercially without too many practical difficulties or excessive costs. The resulting products may serve as an intermediate in esterification and etherification reactions, and in the preparation ol yarns or fibers with improved elastic recovery ability; increased ibsorbency of water, resins, and dyes; water repellency; fire resistance; and crease resistance. In a related paper, Lyman Fourt, Harris Research Laboratories, noted that treatment of cotton with anhydrous cthylamine has a strong decrystallizing action and a strong swelling effect. In this regard, the cthylamine treatment is somewhat similar to the mereerization process. He compared the effect of the two processes on the luster of yarns. Flameproofing Cotton. A series of papers was presented relating to the flameproofing of cotton. George Seidcl, Du Ppnt Co., discussed the development of fire resistance in cotton by the deposition )f titanium and antimony compounds from strong aqueous acid solution. Richard E. Reeves, USDA, stated that a different approach to the problem of introducing inorganic oxides into cotton involves the use of the alkyl orthotitanates, T i ( O R ) , . This method can b e applied under very mild conditions, thus avoiding the introduction of mineral acids. The process appears to consist of an ester exCHEMICAL

change. Lflective flameproofing requires about 11 (/c TiCXs while excellent rotproofing requires about 9 % TiCX·. T o get flameproofing requires high concentrates of orthotitanate and results in loss of excess reagent remaining on the! fabric. The process has several economic I disadvantages including the need to wet! the cotton, then remove t h e water by sol- ' vent exchange. Another drawback is the: need for carrying out t h e reaction in an organic solvent under essentially anhydrous conditions. T h e high cost of the reagent is a further drawback. While the process increases flame resistance, it tends to increase t h e tendency to glow. As a result, even though the titanium loaded fabric may not burn, it will glow to complete consumption. Ordinary glow-proofers decrease but d o not eliminate this trait. Phosphorus for Nonflammability. Phosphorus compounds may b e used to reduce flammahility of cotton. However, because of a cation exchange which takes place during laundering, most phosphorus compounds are removed a n d the flame resistance is lost. Mr. Guthrie stated that investigations are being made to develop phosphorus compounds not subject to cation exchange. One possible solution lies in the use of a polymer containing phosphorus tetrakis ( hydroxymethyl ) phosphonium chloride, a crystalline compound made hy reacting phosphine with formaldehyde and hydrochloric acid. In addition to giving excellent, permanent flame resistance, it imparts crease resistance to t h e fabric. It does, however, result in loss of tear strength. A further drawback is the limited production of t h e compound. AND

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