T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
I092
TABLE III-GBNBRAL
SULIXARY OF
TESTS
Ammonia and CarAmmoMineral bonated Caustic nium Heat RBSISTANCB To: Water Acids Alkalies Alkalies Salts Shock Kavalier Poor Good Poor Goods Good’ Poor M . E . G.Co Goods Good Good’ Goodl Good Poor Pyrex Good’ Good Goods Fair Good Good’ Jena Good‘ Good Good* Fair Good Good: Nonsol Good: Good Goodl Fair Good Goods Good4 Good Good’ Fajr Fry Good Poor Goodl Good Goods Fair Libbey Good Good’ Far superior to any of the other wares.
......... ...... ............ ............. ........... ........... ..... ... ... ... *
Mechanical Shock
Poor Poor Good* Fair Fair Good Good
I n the rating of resistance t o caustic alkalies the boiling tests only have been considered. These results indicate t h a t all the American-made wares tested are superior to Kavalier and equal or superior t o Jena ware for general chemical laboratory use. BUREAU OF STANDARDS WASAINGTON,
D.c.
EFFECT OF COPPER ON CRUDE RUBBER’ By
*
&AS.
P.
FOX
Manufacturers of rubber goods, following the teachings of Pearson,2 have carefully avoided the use of copper salts in their compounds. Coppered iron was used t o a limited extent in vulcanizing rubber t o iron. Copper in this operation has recently been superseded by a plating of other metals. T h e accidental observation of Dewar concerning the marked change of a rubber gasket used in contact with a copper pipe led him t o compare its action with other metals. His tests were made by covering sheet rubber with disks of metals a n d exposing them t o a heat of 150’ F. for several days. His findings were t h a t copper gave the greatest effect, a n d t h a t t h e action was due t o oxidation, copper being a n oxygen carrier. Thompson and Lewis3 took u p the matter and made a n exhaustive study of the action of metals and their salts on vulcanized rubber. Their work was with sheet rubber vulcanized by the Parkes process (cold-cured). The metals, in form of powder, were sprinkled over the surface of t h e sheet and t h e salts, if soluble in water, were made into a paste and applied as a paint. The treated sheets were then exposed for I O days a t a temperature of 60’ C. The action was determined by stretching the test piece. Their results sustained those of Dewar: “Of t h e metals used copper was by far the worst, Copper salts completely destroyed the rubber.” Foden, English textile expert, found that wherever cloth containing copper (used in dyeing) was used in water-proofing, the rubber became hardened and was soon destroyed. Weber4 gives a n explanation of the action of copper on rubber, experimental data and a method of estimating copper in cloth. This method is simple and reliable, and should replace the methods now used in determining copper, in foods. Weber places the maximum limit of copper in cloth for water-proofing a t 0.005 per cent. Weber also noted t h a t t h e presence of grease or oils in t h e cloth facilitated the action of t h e copper. 1 Presented at the 55th Meeting of the American Chemical Society, Boston, September 10 to 13, 1917. 2 “Crude Rubber and Compounding Ingredients.” I Abstract Journal, SOC.Chem. Ind., 10 (1891). 717-718. 4 “Chemistry of Rubber.”
Vol. 9, No.
12
Eschl attributes the action of copper to, the formation of copper chloride which acts as a n accelerator. Morgane states t h a t the presence of copper compounds may cause “tackiness” in crude rubber, and strongly advises against t h e use of copper vessels in the preparation of crude rubber, and even against t h e use of copper insecticides or fungicides on trees during the tapping operation. By experiments made b y riddipg copper salts t o rubber latex, Morgan concludes t h a t the rate a t which tackiness is induced is dependent upon the amount of copper salts used. The formation of resins is t h e main factor in t h e copper-induced tackiness. Schidrowitz3 says t h a t tackiness is due t o a physical degradation of the rubber molecule and not t o a change in its chemical composition. There seems t o be a distinct difference between “perished” or “decayed” rubber (Thompson and Lewis), a n d t h e “tackiness” observed by Morgan. Tackiness as understood by the practical rubberworker is a soft sticky condition affecting crude rubber. Several years ago I became interested in the action of copper on dry crude rubber. Some of these experiments have recently been repeated. I n this particular case the work shows the action of copper in the form of acetate on Pale Plantation sheet crude rubber. Small pieces of this grade of crude rubber were treated with a I per cent water solution of neutral copper acetate; copper acetate solution with I O per cent acetic acid; copper acetate solution with I O per cent ammonia; and oil carrying I per cent of dry copper acetate. Action was checked against blanks of untreated specimens, and with straight oil-treated samples. To observe the action of light two series were run, one ( A ) being exposed t o bright light in a warm room, and the other ( B ) placed in a cool and dark closet. Extremes in a p p l i c a t i o n of the chemical are represented by a single spot, and by i m m e r s i o n for 24 hours. Duration of experiment was approximately 3 months. Each set consisted of six pieces. The original test pieces were mounted on cardboard. These cards were unavoidably lost in transit, preventing their reproduction, and a written description is substituted herewith. Each series was subdivided into two subdivisions: No. I. DROP TEST-One drop of reagent was allowed t o dry on the surface of t h e specimen. No. 11. IMMERSION TEsT-The entire specimen was immersed in the reagent for 2 4 hrs., then dried. The “spot test” gave tackiness a t point of contact between reagent and the rubber. The “immersion test” gave tackiness over the entire surface of the specimen. With the oil experiments even a single drop was too much, while those immersed were ruined (the specimens softened and “run”). All t h e treated samples showed tackiness due t o the reagent. The ammonia copper acetate combination shows a much greater action t h a n copper acetate alone or in combination with acetic acid. The oil1 “Manufacture 2 6
of Rubber Goods.“ “Preparation of Plantation Rubber.” “Rubber.”
Dec., 1917
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y BEPOET O N TESTS
No.
the control or check, untreated. The checks showed 00 chrnge in coior ot texture (a good index of the character of thio grade of n u d e rubber). No. 2 was treated with a I per cent water soivtion of copper Bcetate The reagent produced tnckincss. No. 3 w- treated vith copper acetate solution made acid with LO per cent glacis1 acetic acid. The reagent produced foCkiw88. but net materially greater than in No. 2. No. 4 wm treated with myper acLtafe solution made alkalioe with i o per cent oi atrang ammonia. If reacted strongly with the rubber. giving a hard surince which ezsiiy eceeked. The pmduct resemblcd ‘“perished rubber” (Spiiler’r resin). No. 5 v- treated with lubtiedog nil (containing 25 per cent of rancid vegetabie ail) eanying I per rrzt of dry powdeed copper acetate. No. 6 was trated with the same lllbricating oil a%No. 5 but without copper acetete. Io Nos. 5 and 6 the “immersion” test pieces were spoiled. The test wss tw severe. the ~pedmensbeing destroyed (dissolved in oil). The “drop” tests in both Nor. 5 and 6 showed much action, the oil spread over the cotire surface. Those of NG 5 h i t h copper) showed stronger action than those d No. 6 (without copper). 1 w=
1093
Following these recommendations, t h e City Council appropriated a s u m of money for the establishment of a sewage experiment station, and a citizens’ committee was appointed t o take charge of the work. Prof. C. E. A. Winslow, of Yale University, is t h e chairman of this committee and the director of t h e experiments. During his absence in Russia with t h e Red Cross Commission, Mr. Henry B. Sargent is chairman of the committee. The plant was designed by Prof. S. E. Barney, of Yale University, assisted by Mr. R. H. Skelton. T h e writer is chemist and engineer-in-charge of the station, with Mr. W. S. Sturges
OBSERVATIONS l-copper acetate will produce lackinms in crude rubber. 2-The act;*” is proportianat to amount of reagent and time of *eontact. 3-Influenee of light end heat is not as great (compared with darkaer, and a lower temperature) SLS expected. +The ability of the check samples to “sland W” under the Light conditions indicates the value of Pale Plantation CFepe v*efy 01 crude mbber. 5-The presence of acetic acid did not materially aid in the production of loikinclr. &The presence of ammonia exerted a pronounced influence. The sppedmens, however. exhibited B much different appearance. the miface k d and cracked ?-Lubricating oil (contaitling rnneid vewtable oil) d t b 1 per cent of dry copper acetate gave a greater action than the same oil when used alone.
treated samples should be considered in a separate group as they show results t h a t may arise from washing-mills in bad order. While oils alone exert a powerful action on crude rubber, the presence of copper magnifies this action. Results with oil and copper on crude rubber coincide with the observation of Weber concerning t h e presence oi oil in cloth aiding the action of copper on rubber. The action of the reagent is proportional t o t h e time of application. The influence of light and heat is not is great as expected. This feature of the experiment emphasizes the fact that copper salts induce tackiness in crude rubber indepen(lent1y of the usual causes of this trouble. Considered as a whole the work sustains the views of Dr. Morgan. CLEVHLIND. on10
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COPPER IN SEWAGE AT THE NEW HAVEN SEWAGE EXPERlMENT STATION By F. W. M o r i c m ~ Received September 21. 1917 R E A S O N S FUR INVESTIGATIONS
I n the summer of 1916 representatives of the United States Public Ilealth Service, under the direction of Dr. H . S. Cumming, made an investigation of the sanitary condition of New Haven Harbor. They found t h a t i t was seriously polluted by the sewagc and industrial wastes of New Haven. They recommended that the taking of shellfish from the harbor be prohibited, t h a t bathing be prohibited, and t h a t the city take steps t o insure the proper disposal of the sewage.
FIG. I-ExPs=zxBm
SrrIm~
F ~ GII-BUCBHT. . EL&VITO.
as bacteriologist. Continuous operation started in June of this year. New Haven is an important manufacturing city of i p , o o o inhabitants. The sewerage is on the combined system. Wastes from most of the larger factories are discharged into the East Street sewer, which has an average dry-weather flow of i3,ooo,ooo gallons per day. Since i t was thought t h a t trade-wastes might interfere with the treatment of ibis sewage it was decided to locate t h e Experiment Station at the outfall of this sewer (Fig. I). T h e sewer discharges into tide-water and a t high tide the sewage is backed u p in the sewer for a distance of several blocks. DESCRIPTION OF THE PLANT
The sewage for the testing station is pumped by a bucket-elevator, which was erected in a concrete forebay a t one side of the ?ewer (Fig. XI). T h e sewage is deflected into the forebay by a galvanized-iron deflector built out nearly t o t h e center-line of the sewer, and Rows back into the sewer a t the lower end of the forebay. It was believed t h a t a fair sample of t h e sewage could be obtained in this way, including the floating solids and grease, and that the suspended solids would not be broken u p to ~3 great an extent as if a centrifugal pump were used. Operation of the elevator has shown t h a t it fulfills these expectations. It delivers approximately 1jo,ooo gallons of sewage per day into a hopper-shaped receptacle, from which i t flows over t o t h e station through a wooden fiume
