694
INDUSTRIAL AND ENGINEERING CHEMISTRY
ACKNOWLEDWENT I n the preparation Of this paper free has been made of United States Geological Survey Professional Paper 139, “Geology and Ore Deposits of the Ducktown Mining District,
Vol. 24, No. 6
Tennessee.” The majority - - of the information has been obtained from the management of the two copper companies whose cordial coaperation is gratefully acknowledged. R~~~~~~~ February 25, 1932.
Cellulose in Industry HERVEY J. SKINNER,Skinner and Sherman, Inc., Boston, Mass.
C
ELLULOSE is one of our most important raw materials and one which enters, by way of its many ramifications, into the daily life and routine of every individual. Cellulose is the essential constituent of all vegetable tissues and fibers. It is the chief raw material of the textile and paper industries and more recently has become the raw material from which a wide variety of new products are made. The sources of cellulose are legion and may be classified in a number of ways. A classification according to the part of the plant from which it is derived will perhaps be first in order so as to present a proper picture of the many varieties of cellulose : First, there are the seed fibers which are borne on the seeds or on the inner walls of the fruit or capsule. Cotton is the principal and by far the most important member of this class which also includes kapok and other flqsses or silk-cottons. Second, there is the cellulose in the fihers of which the inner bark or bast tissue of the plant stems is composed. As these fibers appear in commerce, they are not individual cells like the cotton fiber, but are aggregations of numerous small elongated cells, the so-called ultimate fibers. In this clam we find flax, hemp, jute, ramie, and other grasses, such as the cereal straws, cornstalks, sugar cane, and esparto. Third, there are the fibers which are ot&ned from the leave3 of the plant and which are similar in ch:u.acter and closely related to the bast fibers of the preceding clars. This class includes Manila hemp, Sunn hemp, Slsal hem and related fibers. Fourth, we have the woody fiber oftrees which consists of the various elements of which tbe fibrovascular tissue of the wood is composed.
A classification in accordance with the industrial uses of cellulose may be simpler and more logical. Four groups come within such a classification: 1. Fibers used in the textile industry. 2. Paper-making fibers. 3. The purified celluloses which form the raw materials for the preparation of the cellulose derivatives. 4. A miscellaneous group consisting of the fibcrs used in corda e, as stuffing materials for upholstering, ria brush and mat €item, and for a number of minor uses.
A fifth class might be added-the cellulosic materials of the lumber industry-but these will not be discussed in this paper except in their bearing as sources of cellulose. TEXTILE FIBERS
COTTON. The purest form of cellulose which occurs in mature is cotton, which contains more than 95 per cent of cellulose. It consists of the unicellular hairs which are attached to the seed of the cotton plant. It is indigenous to nearly all subtropical countries but appears to be best capable of cultivation in warm humid climates where the soil is .sandy. The principal centers of cultivation are the southern part of the United States, India, and Egypt. Cotton is also raised in various other parts of the world-notably China,
Russia, South America, the east and west coasts of Africa, and the West India Islands- but these sections are relatively unimportant as compared with the United States, India, and Egypt, which together produce approximately 85 per cent of the world’s cotton crop. New and large areas in Russia recently opened up for cotton cultivation may make that country an important factor in the world market. The cotton belt of the South, embracing the thirteen states situated in the coastal plain extending from Virginia and North Carolina to Texas, is the most important cotton-producing center in the world. The area devoted to the raising of cotton in this cotton belt is approximately 45,000,000 acres, or over 98 per cent of the total United States cotton acreage. The 1930 cotton crop from this section amounted to 13,700,000 bales or 6,863,000,000pounds. Slightly over half of this amount is exported, the balance being consumed in the United States. The manufacture of cotton textiles in the United States is centered in two areas-the northeastern section (around New England) and the South. While Beverly, Mass., is credited with the distinction of building the first cotton mill in the United States in 1787, historical records show that during the same year a mill was erected near Charleston, S. C. At any rate, the South began the manufacture of cotton goods a t a very early date. It was discouraged, however, by many of the leading citizens of the South. Thomas Jefferson was opposed to it, believing that the people would be happier and more virtuous and prosperous in the pursuit of agriculture than they could be with the vices and evils of manufacturing towns in their midst. The tariff laws a t that time intensified the opposition to this branch of industry, and John Randolph in a speech in the House of Representatives in 1824 declared that if there were no other obstacles, the climate was against it. Notwithstanding this early opposition, the industry grew gradually until toward the end of the nineteenth century, when spindles and looms began to appear in greater numbers in the South. Up to about 1913, the industry grew in the North and South a t about the same rate, but since that time the South has forged ahead of the northern section, so that in 1930 the South produced 67 per cent of all the domestic cotton goods manufactured, and consumed 73 per cent of all the cotton used in American mills and 20 per cent of the entire world’s cotton consumption. The length and the character of the cotton fiber or staple are the most important factors that determine the value of cotton. Commercially, cotton is divided into two classes: short staple of 11/18 inches and under in length; and long-staple cotton of 11/8 inches and over in length of fiber. The length and strength of fiber produced in any locality depends on the variety planted, the soil, climatic conditions, and cultural methods. The processes through which the raw cotton passes are entirely mechanical. The lint or fiber is separated from the seed in the cotton gin, after which the cotton is baled and
June. 1932
INDUSTRIAL AND ENGINEERING CHEMISTRY
695
shipped to tile textile plants, where the spinning and weaving that ramie has the most perfect crystalline structure of any of processes are also mechanical. the natural vegetable fibers, ranking next to the mineral fiber, Physically the cotton fiber consists of a long tubular cell asbestos. This fundamental fact explains why the fiber is with one end attached to the seed. The outer end of the tube uniquely lacking in elasticity and adequate twistingproperties, is pointed and closed. While growing, the fiber is round and a fault which has heretofore heen attributed to improper methcylindrical, having a central canal running through it; but, ods of decorticating and degnumming. I n vie-, of this funas the fiber ripens, the juices in the inner tube arc d r a m back damentally important property of ramie, it would appear u s e into the plant and dry up on exposure to light and air, causing less to attempt to develop a ramie industry in this country to the fiber to fiatten and become twisted into an irregular spiral compete with the firmly entrenched cotton industry. or screwlike hand by reason of the unequal collapse and conMARI;ETINO OF C o n o x . Both the cotton grower and the traction of the cell wall. This twisted condition of the cot- cotton user have benefited by researcli and the application ton fiber is of great economic importance, since upon this of science, hut the crying need of the industry as constituted characteristic depends its adaptability for spinning, the fibers today is improved marketing methods. Tire economic phases locking themselves together into a strong compact thread. of cotton growing have not changed materially since the Civil MISCELLANEOUS TEXTILE FIREIW.The other textile fibers War. The world demands cotton ranging from ‘/g to Is/,& of cellulosic origin which find application in the textile in- inches in length of staple. The production of short-staple dustry are important but relatively insignificant in comparison cotton in the United States has heen increasing, and the longer with cotton. Flax or linen, jute, hemp, and similar bast fibers staple of 1 inch and over is becoming a smaller proportion of have important uses in certain fields which have never and the crop. The main reason why the shorter staple is grown are not likely to encroach on cotton. These fibers have sev- in larger quantities is that the average farmer cannot get any eral fundamental differences which preclude competition with better price for medium- than for very short-staple cotton. cotton in the textile field. I n the first place, they differ radi- This condition in the cotton industry is directly traceable to cally from cotton in that they consist of bundles of ultimate the public gins and the commercial system of indiscriminate fibers ccmented togetlier by other vegetable tissue, whereas buying. Although the present-day public gins are more efcotton is a single elongated cell, free from transverse parti- ficient than the old plantation gins, they have a serious drawtions. Bleaching and other chemical treatments have a dis- back. The farmer takes his cotton to the public gin and resolving or disintegrating action on the cementing material of ceives back his cotton and seed. Different kinds of cotton these fibers, which explains why they are less resistant to follow each other at the gin, resulting in mixed cotton and chemical treatment than cotton. mixed seed. I n growing special varieties of cotton, it is just Furthermore, the cell walls of these fibers are usually par- as essential that the cotton and seed be kept separate a t the tially changed from pure cellulose into lignin and degraded giu as it is to isolate the field where it is grown. The farmer sells his cotton in the primary market at “hog cellnloses, and are thickened, which decreases their flexibility round” prices with no discrimination between length of staple and general adaptability to textile processes. RAMIE. China grass or ramie should he particularly men- or other qualities of the fiber. Cotton is not graded to any tioned because of its apparently remarkable properties and extent in these prirnary markets, but at the shipping centers also in view of the more or less recent attempts to introduce where thousands of hales are assembled. Much cotton is grown on advances of borrowed money, but its growth in the South. I n reality, ramie and china grass are two distinct fibers; but, as they appear in commerce, no the banks or other loaning agencies have paid little or no atdistinction is made. Ramie is grown in almost limitless tention to quality. I n most cases the farmer raises cotton quantities throughout equatorial Africa, India, and China, and enough other crops to feed his family and livestock. C o t t o n b e i n g the o n l y a l t h o u p h t h e last-named country-prduocs the best money crop, he is forced to fiber. turn it into cash as soon as The ramie fiber is excepit is in the bale, particularly t i o n a l l y l o n g a n d very if it is grown on borrowed s t r o n g and durable. It is money. comparable t o bleached If the cotton were sold by cotton in color, and can be the farmers in the same way s e p a r a t e d to a l m o s t tlie that it is sold to the manufineness of silk. It is natufacturers, there would be no ral, therefore, that a fiber difficulty in i m p r o v i n g of such remarkable qualiq u a l i t y . T h e manufacties should a t t r a c t attenturer pays more for longtion. The use of ramie in staple than for short-staple India and China dates back c o t t o n ; b u t , under t h e existing system of grading to prehistoric times, and innumerable attempts have the c o t t o n a f t e r it has been made to develop pro+ passed the primary market, esse for decorticating and the middleman receives the premium rather than the deguniming t h e fiber. farmer. Consequently T h e s e h a v e n e v e r heen successful, with the result there is no incentiw for the latter to grow s u p e r i o r that the difficult separation fibers. of the fiber proper from the European customers rest of the plant tissues is have complained of the still done by hand labor. f a l l i n g off in q u a l i t y of Comparatively r e c e n t American cotton, and the work with x-ray analyses of FARXEXSWAITINGAT PUSLZC GIN s e r i o u s n e s s of the situafibers has disclosed the fact (Emh wagon may oontain different kind oi aotton)
69G
IhDDJS7'1iI \ I
