Rayon from Alginic A c i d Being Developed in England r\RY seaweed contains 15 40% alginic acid, which is readily extracted. When seaweed is treated with sodium car bonate solution, the plant undergoes dis integration in 24 hours, forming a gelatin ous mass, which is diluted with water and filtered. The filtrate is bleached and ster ilized with sodium hypochlorite, then acidi fied with hydrochloric acid to precipitate the alginic acid. After being washed, the alginic acid is again neutralized with so dium carbonate to yield sodium alginate. This material was available in powder form before the war, but no serious attempt had been made to examine its possibilities as a raw material for rayon manufacture, despite the existence of abundant supplies of seaweed ofif the west coasts of Scotland and Ireland. Alginic acid was isolated by Stanford in 1884, and in 1930 was recognized as a poly mer of c?-mannuronic acid. Its molecular weight is high, but varies with the mode of isolation; osmotic pressure determinations on a series of sodium alginates, dissolved in 0.2 Ν sodium chloride solution, gave values of 48,000 to 185,000. Carbon and hydrogen determinations suggested the formula (CeHeOe)n, and the neutralization equiva lent was found to vary from 176 to 184. Two suggestions· have been made re garding its mode of polymerization, the
HO Η
HO
Ή
-V
HCOH
HCOH
HCO HOCH
HCO— HOCH
HOCH
HOCH
COOH
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first by Dillon and McGuinness, and the second by Lunde, Heen, and Oy. The au thors favor the second of these. Alginic acid fulfills the requirements of a substance for the manufacture of fibers. It consists of chain molecules of high molecular weight, with reactive sidechains, and abundant supplies are avail able. Solutions of the soluble alginates, e.g., sodium alginate—are sufficiently vis cous for spinning on the viscose rayon system, and are readily coagulated by dilute solutions of strong acids to give filaments of alginic acid, or by salts of metals to yield alginates. In producing alginate yarns, the me chanical principles of viscose rayon prac tice were adopted. A filtered solution of sodium alginate is fed to a gear-wheel pump, from which it passes to a candle filter. The solution flows through a glass tube to a tantalum spinneret, immersed in a coagulating bath. The filaments are drawn off by a revolving glass godet, and passed through a traversing funnel into the Topham box where the yarn is wound into cake form. In its details, however, the process differs from viscose spinning because of the peculiar properties of al ginic acid and the alginates. Rayon of satisfactory handle, appear ance, and strength may be obtained by ex truding a solution of sodium alginate into a bath containing iV-calcium chloride, 0.02 Ν hydrochloric acid, and 2.5% by volume of olive oil emulsified with 1% Lissapol C (I.C.I.). The olive oil was used to keep the filaments separated during drying. Otherwise, the filaments are harsh and strawlike, as they are swollen when first spun, and adhere to one another while drying. The bath for the production of alginic acid rayon consisted of ΛΓ-sulfuric acid saturated with sodium sulfate, 2.5% olive oil emulsified with 1% of Fixanol
COOH
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Condensed from the following articles in British publications: (1) Speak man, J. B . , and Cham berlain, Ν . Η., "The Production of Rayon from Alginic Acid'*, The Journal of the Society of Dyer» and Colourists, 60, 264-272 (1944); (2) Cham berlain, N . H., Johnson, Α., and Speak man, J. B., "Some Properties of Alginate Rayons", The Journal of the Society of Dyers and Colouristt, 61, 13-20 (1945); (3) Speakman, J. B. t "Rayon from Alginic Acid", Chemical Trade Journal çnd Chemical Engineer, 116, 614, 616 (1945).
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(I.C.I.). The yarns produced from these baths retained 2 % by weight of olive oil, which was a useful lubricant in subsequent weaving and knitting. The concentration of the sodium alginate solution should be fairly high, as the best handle is given by a solution containing 7.5 to 8.0% of the dry alginate. For convenience in spinning, the grade (mole-
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1945
cular weight) of the alginate should be chosen so that the solution has a viscosity of 100-150 seconds at 25° C , as determined by the falling sphere viscometer, using 6/82 inch steel balls. Under these conditions, no difficulty has been encountered in producing yarns with a strength of 2.0 grams per denier at 65% relative humidity, in deniers as low as 2 deniers per filament. This compares with values of about 1.3 and 1.8 grams per denier for cellulose acetate and viscose rayons, respectively. Alginic acid and calcium alginate are readily dissolved in a solution of soap (0.2%) and soda (0.2%). However, this defect can be turned to advantage. For example, when a fabric is woven from yarn prepared by twisting together cotton and calcium alginate yarns so as to remove the twist from the cotton yarn, subsequent scouring leaves a cotton fabric composed of yarns entirely without twist; fabrics of this type have already found a number of applications. Secondly, if a fabric is woven from yarns prepared by twisting together mohair and calcium alginate in such a way as to cause the mohair to wrap around the alginate, the extra length of mohair is released to form loops on the surface, when the fabric is scoured. The production of alkali-reswtant rayons was then investigated. It seemed that success might be achieved by cross-linking alginic acid with metals of high coordinating power, such as chromium and beryllium, instead of calcium. Unfortunately, satisfactory filaments were not obtained by direct spinning of sodium alginate solution into baths of chrome alum and beryllium sulfate. They were, however, obtained by treating alginic acid rayon and .calcium alginate rayon with the basic acetates of chromium and beryllium. Yarn containing 1.29% chromium and 9.04% calcium, prepared by treating calcium alginate with .a 2% solution of one-third basic chromium acetate, was undissolved after immersion for 27 hours in a soap and soda solution at room temperature. Similarly, a yarn containing 2.89% beryllium and 5.20% calcium, prepared from a basic beryllium acetate solution, is also alkali-resistant. Chromium and beryllium alginate rayons prepared from alginic acid suffered a less than 5% loss in tenacity on treatment with a solution of soap and soda for 30 minutes at 25° or 40° C , and the beryllium alginate yarn, which is more useful in being uncolored, had a tenacity of more than 2 grams/denier. 1717
Alkali-resistant rayon can also 1M* cont a i n e d by cross-linking a c i n i c acid yarn w i t h formaldehyde. The yarn is treated w i t h a solution of ammonium rhloride an, and 100';; K.H. and 2:»° C. showed that the extensibility of chromium and beryllium alginates is much too low to permit their successful use in weaving and knitting. Calcium alginate rayon possesses satisfactory elasticity for these purposes, and as it can be stored for long periods it seems likely that it will form the stock material for all purposes—for conversion into woven and knitted fabrics, which can b e made alkali-resistant with chromium or beryllium acetate, as well as for special uses in which its alkali-solubility is an advantage. Uginate rayons have a marked aftiniu for basic dyes. In addition, they can he dyed with selected direct dyes and, when the yarns contain chromium or beryllium, with mordant dyes. Therefore, there is good reason to believe that the seaweed rayons will find an important place in the textile industry of the future.
Engineers1 Program for Control of German Industry to Prevent Rearmament Recommendations of National Ensinecrs Committee, selected from five engineering societies, and based on year's study by 35 leading engineering and technological specialists have been submitted to State, War, and Navy Departments, Commanding General of Army Service Forces, Foreign Economic Administration, and authorities in .American Occupied Z o n e in Germany. The five-point program proposed is here outlined. EL FIVE-POINT program for strict control ^ * of German industry, from raw materials to processing and scientific research, i n order to prevent rearmament, has been formulated by the National Engineers Committee of the Engineers Joint Council o n t h e basis of studies made b y 35 leading engineers and technological specialists and jQade public after transmission to the appropriate XJ. S. authorities. The study was begun last February with the approval o f t h e State and War Departments. Prohibition or Control of Five War Essentials Working within the framework of the Y a l t a and Potsdam agreements, the engineering group concludes that assurance that Germany will keep the peace requires institution and maintenance of effective controls of power production and distri1718
bution and industrial plant construction: (1) prohibit the synthetic fixation of nitrogen; (2) prohibit the production of synthetic liquid fuels; (3) prohibit the production of aluminum; (4) prohibit t h e development or use of atomic energy ; and (5) limit the capacities and production of steel and steel products plants. It also is proposed to eliminate danger from secret scientific research by preventing coordination of such effort with development facilities under German control. Economic subsidies t o industry by t h e German Government are ruled out a s a fruitful source of future war strength. Copies of the report and recommendations have been laid before the heads of t h e State E>epartment, the War Department, the N a v y Department, the Commanding General of the Army Service C H E M I C A L
Forces, the Foreign Economic Administration, and General Lucius D . Clay, deputy to General Eisenhower for U. S. Group Control Council for Germany. Specialists in the fields of construction, power, the materials t o be eliminated or controlled, and research organized into a task committee for each particular field The recommendations are regarded as the most authoritative and complete data on German industrial potential, its needs for normal civilian economy, and where the line should be drawn t o prevent rearmament. T h e scope of the committee's studies, according to t h e directive of the Engineers Joint Council to the National Engineers Committee, includes industrial control of all aggressor nations. Its first report deals entirely with Germany. To Avoid Economic Vacuum T h e report is built around the expressed philosophy that "it is necessary to subtract from aggressor peoples, for a long period of recuperation, the fundamentals of their industrial war potential for armed aggression", but that ''complete elimination of German industries, leaving agriculture a s the sole occupation, would produce an economic dislocation and social chaosof destructive magnitude, not alone in Germany but throughout Europe". Framers of the report believe their A N D
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