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INDUSTRIAL AND ENGINEERING CHEMISTRY
upon the availability of the wood cellulose. Present production capacity of chemical wood cellulose in this country is not sufficient to anticipate this demand except by a curtailment of consumption in less important fields. Such restrictions would unquestionably be imposed by government regulation should the need arise. Basically there is a sufficient supply of recurring wood resource in this country to extend producing facilities that will make the country quite independent of European wood pulps. The successful utilization of wood cellulose from sources that had until recently been deemed wholly unsuitable for chemical conversion gives complete assurance of adequate supplies for any conceivable requirement over the immediate future. The southern pine development, as well as the recently achieved hardwood cellulose industry in the North, gives ample proof of vast untapped timber supplies comprising wood species that have a substantially faster growth rate than is enjoyed by the northern spruce and fir. I n addition to the justification of new pulp-producing units, there is the added knowledge recently acquired that the kraft pulps, which have hitherto been considered unsuitable for conversion into viscose, can now be processed into bleached products which respond nicely to the xanthate reaction and yield a satisfactory rayon. Thus, huge present-day productions of the alkaline-cooked fiber could be diverted from the coarse-paper field to the rayon industry if a demand arose precipitously. Nitrocellulose for munition purposes is ordinarily produced from a cotton linter base if i t is available in sufficient amounts. I n the first World War large quantities of sulfite wood pulps were nitrated by the Central Powers to augment the supply of nitrocotton. The more highly refined wood celluloses of today are equivalent to cotton in most respects and can be directly substituted to yield a nitrated fiber that has the required stability and nitrogen content. I t s adoption in an emergency is already anticipated. The vast array of cellulose base lacquers that have become commercially available in recent years will become an integral part in a war procurement program. The list will include derivatives of which the acetates, the nitrates, mixed esters, and the ethers will assume a prominent role. All can be produced satisfactorily from a cotton or a wood-cellulose base. Other procurement schedules will determine which will be designated for this use.
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The development of cellulose plastics has advanced at a rapid pace in the last few years. Quite aside from the ornamental wares that intrigue the fancy of the housewife, real progress has been made in the fabrication of commercial articles of substantial size and a t costs that permit their use for many purposes. Light weight, toughness, and molding properties will favor the adoption of plastics over the metals in several fields, both of a domestic and military nature. The wood celluloses are eminently suitable both as a chemical base and as a fiber filler that is frequently employed to impart added strength and toughness to the plastics composite. Application of wood-cellulose plastics is predicted to assume considerable importance in any modern war program. The art of felting wood-cellulose fibers into paper or other similar form has been greatly benefited by the advent of a host of wood pulps that possess new and peculiar properties. Certain pulps that are high in alpha-cellulose have made it possible to prepare a felt that is highly adsorbent, of superfine structure, and very serviceable as a gas-mask filter m e dium. Other felts of similar composition are now used extensively for impregnation with rubber mixtures, resins, and cellulose derivatives to create a family of leatherlikc products which have already found wide commercial use and will no doubt supplement leather in its various applications for war purposes. The complete list of special paper items in a war schedule will include the reinforced paper-asphalt composite, waterrepellent paper that has been coated with flexible lacquers, a sheet that will retain its full strength when saturated with water, paper clothing suitably impregnated for gas protection, parchment sheets, and vulcanized board. There will be woodcellulose wadding as a substitute for absorbent cotton in surgical work, and wood fiber containers for powder charges to replace the sheet metal that has been used in the past. The wood-pulp industry is well equipped to cooperate with governmental agencies in the task of evaluating the various types of wood cellulose in a war schedule. Knowledge that is not directly applicable to the immediate needs of a peacetime requirement but which may find important use by a nation a t war is available in the many established laboratories of the country. It can be searched out and capitalized if means are provided for proper interchange of basic knowledge and potential need.
NYLON JAS. K. HUNT, E. I. du Pont de Nemours MONG the fourteen items on the list of strategic materials is silk, of which the United States last year imported approximately 51,000,000 pounds. While about 75 per cent of this yarn went into hosiery (not exactly a strategic use), considerable quantities found application in the manufacture of certain essential military products, including parachute fabrics and shroud lines, powder bags, and flare cloths. For the manufacture of such textiles a yarn is required which combines high elasticity and tensile strength with light weight, and until recently silk was the only material which satisfactorily met the requirements. With the advent of nylon yarn, however, a truly synthetic material has become available which appears to possess many of the desired characteristics. Yarns can be spun from nylon which, weight for weight, have a higher factor of combined tensile strength and .elasticity than that of any commonly used textile yarn; this
A
& Company, Inc., Wilmington, Del.
suggests that the new material might be used for the above indicated military purposes. It is of interest that nylon is also finding application in the manufacture of bristles for both toilet and industrial brushes. Whereas most animal bristles are imported from the Orient, and are accordingly subject to variations in quality, price, and ease of procurement, nylon bristles are derivable from domestic raw materials-coal, air, and water. Under a variety of service conditions nylon bristles have shown greater durability than animal bristles of the same size and weight. Late in 1939 the first spinning machine for nylon yarn was started in du Pont’s new plant at Seaford, Del. This initial plant, when in full operation, has a capacity of approximately 4,000,000 pounds of nylon yarn per year. I n addition to yarn, the Seaford plant produces the flake nylon, which is subsequently made into the monofilament used as bristles, fishing leaders, surgical sutures, etc.
