An Apparatus to Demonstrate the Continuous Manufacture of Rayon EDWARD F. JENKINS, GEORGE E. GABUZDA, and H. ALBERT SANER Villanova College, Villanova, Pennsylvania
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NE of the exhibits which attracted most attention a t a recent "Open House" was a miniature plant for the manufacture of rayon. Washburn (1)and Scharf (2) have previously described the preparation of rayon threads. The present apparatus produced a lustrous, uniform-diameter fiber of cellulose rayon, and operated continuously for several hours. Filaments as long as forty meters and capable of suspending a 100gram weight have been made. The plant can be constructed a t a low cost. The apparatus was arranged as shown in the line drawing and accompanying photograph. The cuprammonium process was used in preference to the viscose process because the spinning solution is much easier to make. Students should be advised, however, that fourfifths of our rayon today is made by the viscose process.
APPARATUSFOR
DEMONSTRATING TAE CONTINUOUS MANUFacrmE a E RAYON
SPINNING SOLUTION
Schweitzer's Reagent was prepared by dissolving 60 g. of cupric hydroxide in one liter of 28 per cent ammonia. Cupric hydroxide is conveniently obtained by precipitation with ammonia from cupric sulfate; it is essential that this operation, as well as the drying on a porous plate, be conducted a t low temperature to prevent conversion into cupric oxide. Thirty grams of cotton were pulled into rope form and cut into sections one cm. in length. These were dissolved in the liter of reagent by mechanical stirring, about three hours being required. The mixture was filtered through glass wool, diluted with an equal volume of 28 per cent ammonia, and protected from light. COAGULATION
The spinning solution was placed in an ordinary fuunel to the stem of which was attached a finely drawn capillary bent a t right angles; an orifice diameter of 0.7
APPAXATUS FOR
mm. was found to work well. Smaller orifices produced a single filament which was too weak, while too large an orifice produced a weak, hollow thread. The solution flowed from the capillary into a solution containing 10 per cent glycerin by volume, and 33 per cent sodium hydroxide by weight. The concentration of this solution, as well as that of the acid and soap solutions, was that recommended by Scharf ( 2 ) . The coagulating bath ( A ) as well as the first wash bath ( B ) should be as long as possible; in the present setup they were 75 an. long. SUBSEQUENT BATHS
From the coagulating bath the thread was fed under a glass rod held in place by rubber policemen and over a well-greased bakelite pulley, held in place by a rubber stopper, into bath B. All the baths were similarly equipped. Varying the position of the glass rods controls the time the filament remains in the bath.
DEMONSTRATING TEE MANIJPA~URE OR RAYON
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Bath B was tap water, which should preferably be continuously renewed. Bath C was two per cent sulfuric acid. Bath D was tap water. Bath E was one per cent soap and one per cent glycerin, and was heated to about 70°C. Bath F was tap water. DRYING AND RATE OF PLOW
From bath F the thread was drawn for about one meter through the air and wound upon a glass rod revolving in the chuck of a variable speed stirring motor. While it was m o v i n ~throueh the air the filament was dried by a blast of hzt air frlm a hair-dryer. The speed at which the thread can be drawn through the baths depends on the diameter of the thread and the length of the baths. I t should be removed from ~
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the acid bath as soon as it is decolorized. Under favorable conditions the plant ran without interruption for periods of two hours. When the thread broke it. could conveniently be knotted and the process continued. Due to the friction of the rods and pulleys the thread was stretched as it passed from bath to bath uuti1 the diameter of the final product was approximately 0.3 mm. Further interest can be added to the process by dyeing the dried thread. A direct cotton dye, such as Congo Red, is recommended. LITERATURE CITED
(1) W~snarmn,"Lecture demonstrations for general chemistry," J. CHEM. EDUC., 5,96 (1928). (2) SCHAR", "The laboratory preparation of rayon according to the capper process," 2. pkysik. chem. Unlerricht, 49, 119 (1936); abstracted J. CHEM. EDUC.,13, 546 (1936).
