INDUSTRIAL A N D EiVGIhTEERING CHEMISTRY
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The ease of sampling, portability, and general simplicity of the scheme were brought out and its practical field value was demonstrated.
BIBLIOGRAPHY 1-Price and Brown, “Dust Explosions,” National Fire Protection Association, July, 1922. 2-Fieldner, Katz, and Longfellow, “The Sugar Tube Method of Determining Rock Dust in Air,” Bur. Mines,Tech. Paper 218. 3-Palmer, Coleman, and Ward, “Methods for Determinations of Air Dustiness,” A m . J . Pub. Health, 6 (1916), 1049. 4-Erady and Touzalin, “The Determination of Dust in Blast-Furnace Gases,” J . I n d . Eng. Chem., 8 (1911), 662. 5-Trostel, “Efiiciency of the Palmer Apparatus for Explosive Carbonaceous Dusts,” J . A m . SOC.Healing Ventilating Eng., 28 (1922). &-Simon, Slahl u. Eisen, 26 (1905), 1069. 7-Mariner and Hoskins, Report to Chicago Association of Commerce Committee on Smoke Abatement and Electrification of Railway Terminals. Laboratory Report on Air Analysis, 1915.
&Brown,
Vol. 15, KO.3
“Inflammability of Carbonaceous Dusts in Air,” J . I n d .
Eng. Chem., 9 (1917), 269. GFieIdner, Oberfell, Teague, and Lawrence, “Methods of Testing Gas Masks and Absorbents,” Ibid., 11 (1919), 619. 10-Wells and Gerke, “An Oscillation Method for Measuring the Size of Ultramicroscopic Particles,” J . A m . Chem. SOC.,41 (1919), 312. 11-Armspach, “Theory of Dust Action,” J . Am. Sac. Hearing Ventilattng Eng., 26 (1920), 819. 12-Wilson, “Humidity Control b y Means of Sulfuric Acid Solutions,” J . I n d . Eng. Chem., 18 (1921), 326.
ACKNOWLEDGMENTS The authors are particularly indebted to the Pittsburgh Experiment Station of the Bureau of Mines for making available some of the special apparatus used in this study, as well as to the Western Maryland Railroad for permitting tests to be conducted in their elevator.
T h e Effects of Waterproofing Materials and Outdoor Exposure upon t h e Tensile Strength of Cotton Yarn’ By H. P. Holman and T. D.Jarrell BUREAUOF CHEMISTRY,U. S. DEPARTMQNT OF AGRICULTURE, WASHINGTON, D. C.
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T IS commonly known
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In the experiments described, unbleached and unsized warp yarn three lots. The variation was treated with various waterproofing materials and exposed to the in tensile strength within that Some Waterproofing materials, Particuthe individual lots was not weather to show the eflects on tensile strength, After one year’s exposure the treated yarn was in most cases stronger than the unSO great. 1arlY the drying Oils, injure treated yarn after exposure, but weaker than the treated yarn before Each skein was subdithe strength of cotton fabTics, causing them t o ‘‘rot’’ vided into smaller skeins of exposure. With three treatments containing asphalt there was no within a ComParativelY material loss in tensile strength. Raw drying oils caused more such length that four series deterioration than the same oils previously boiled with metallic of tensile-strength tests of short time. While tigating the value of variat least ten each could be driers. Semidrying and nondrying oils, in most C ~ S C S , caused as OUS materials for watermuch deterioration as the raw drying oils. The addition of burnt made. These small skeins umber to a drying-oil treatment had a marked preservative eflect. were treated at intervals Proofing and mildew-Proofing fabrics for farm and during the spring, summer, and fall months in other uses, the Bureau of Chemistry found that a number of other substances also in- series of from ten to twenty, and were exposed to the weather, jure the strength of cotton fabrics. In order to select those together with controls consisting of the untreated yarn of treatments which are least injurious, a series of experiments both sizes. Only one lot of yarn was used in each series, was conducted in which cotton yarn, such as is used in and the results were figured separately for each series by comthe manufacture of high-grade cotton duck, was treated parison with the controls for that series. with various materials, exposed to the weather, and tested The treatments were applied by drawing the garns through periodically for tensile strength. the materials in liquid form, in their ordinary condition, in solution, or after fusing. Glass tubes bent like the letter J, OUTLINE OF EXPERIMENTS with the short arm ending in a tip of capillary tubing and sincesize was thought to be a possible factorinfluencing with an opening in the tube directly beneath this tip, were the rate of deterioration of treated yarn, two Sizes-No. 7, used to guide the yarns through the liquids. The emergent Off the excess4-ply, and No. 13, 3-ply-representing coarse and medium tips After treatment, the Yarn was allowed to dry for ten days, . yarns, were selected. The samples procured for the work mere unbleached and unsized ffarp yarns such as are used in after which it was Weighed to determine the amount of the manufacture of No. 4 (heavy weight) and No. 10 (medium treating material applied. The weight of yarn before and after treating was determined weight) duck according t o specifications of the Ordnance and all tensile-strength tests were made in a room maintained Department .z Three lots of yarn, each consisting of one skein of each of at a constant relative humidity Of 65 per cent a t a temperature the two sizes mentioned, weye used in the experiments. of 70” F., and after the samples had remained in the room. Two lots were from one manufacturer of cotton duck and the for at least twenty-four hours. After TVeighing, ten tests of tensile strength Were made on third lot from another. The tensile strength of the 7/4 yarn varied from 4.8 to 5.8 kg. for all three lots, while the tensile each of the treated Yarns, as well as on samples of the unstrength of the 13,’s yarn varied from 1.9 to 2.9 kg. for all treated yarn, to determine the immediate effect of the treatment before exposure. The remaining yarn from each Presented before the Division of Indus1 Received August 25, 1922. treatmentwas wound on an open wooden frame, and was extrial and Engineering Chemistry at the 62nd Meeting of the American posed to the weather in the open country in a location where Chemical Society, New York, N. Y . , September 6 to 10, 1921. it would not be shaded from the direct rays of the sun or * Teztzle World J , 67 (1919), 241.
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I N D U S T R I A L A N D ENGI ‘NEERING CHEMISTRY
sheltered from rain, and where it would not be affected by other agencies, such as gases or vapors normally absent from the atmosphere, smoke, dust, mildew, or bacterial action. (Fig. 1) Samples were removed and tested for tensile strength a t intervals of four months, the last test being made one year from the time the material was first exposed. All tests were made on single strands of yarn by means of tensile-strength machines of a standard type.
AMOUKT OF TREATIXG MATERIALS ON YARN As a rule, there was no regularity in the amount of treating material held by the yarn. However, it is probable that in most cases the yarn was saturated and held in addition more or less of the material on the surface, in spite of the use of a scraping device during the treatment. The excess depended on the nature of the treating material, being greatest in the case of the viscous oils and the materials applied in fused condition.
IMMRIEDIATE EFFECTS OF TREATMENTS The immediate effects of the treatments upon the tensile strength of the yarn are for the most part due to physical causes, since it usually requires some time for chemical changes resulting from the treatments to become apparent. One marked exception is the treatment with rubber solution followed by cold vulcanization with fumes of sulfur monochloride, where the injurious effect of the hydrochloric acid formed was immediately observed. Some treating materials may lubricate the individual fibers of the yarn, causing them to pull apart more readily. Others may cement the fibers together, or make them swell, thereby causing them to pull apart less readily. For instance, a piece of the yarn dipped in heavy mineral oil and tested immediately showed a tensile strength of 16 per cent less than that of the dry yarn, whereas another piece of the same yarn dipped in distilled water and tested immediately showed a tensile strength 9l/* per cent greater than that of the dry yarn. I n some cases, where the immediate effect has been an increase in strength due to the cementing or stiffening effect of the treatment, a part of the increased strength is soon lost because the treating material is brittle and breaks off the surface where a large portion has been carried, or because the chemical action of the treatment reduces the strength of the cotton fibers, offsetting the strengthening effect of the treatment. TABLEI-COMPARISONOF DETERIORATION RESULTS OBTAINED WITH DUPLICATE TREATMENTS AFTER 4, 8 AND 12 Mos. EXPOSURE IN DIFFERENT SEXSONS VARIATION FROM TENSILE STRENGTH OF TREATED YARNEEFORE EXPOSURE^ After
After 8 Mo.
12 Mo.
-53.5 -17 -34.5
-54 -34.5 -36.5
-59 -36 -40.5
Asphalt, Bermudez, refined
-41 -15.5 -31 -17.5 -13.5 -15.5 -34.5 -24 -60 -53 -21.5
Copper oleate, technical
-29
Lead oleate, technical
24: -13.5 -35.5 -28.5
-36
