INDUSTRIAL A N D ENGINEERING CHEMISTRY
1788
dissolved oxygen content of the water is the most important factor governing the solution of copper from pipe walls. The p H is the next most important factor; the solution of copper is favored by a low pH. The use of untinned copper f o r t h e transport and storage of hot and cold water is permissible if the walls are continuously in contact with water, unless the p H calculated from t h e free carbon dioxide and bicarbonate content is 6.9 or lower and the dissolved oxygen is over 3 parts per million. Tinned copper or copper with a tin lining can be used in doubtful cases. Pomfret and Mosher (38) call attention t o the good service t h a t can be obtained from copper piping in sea water at moderate velocities, but copper may be badly corroded by sea water at velocities of 5 feet per second or higher or at temperatures above 110’ I?. They report t h a t wiped coatings of lead-tin solder on copper give considerable protection, but not against high velocities. Dipped tin coatings were considered ineffective. LITERATURE CITED
Allen, J, F., and Mendoza, E., Proc. Cambridge P h i l . Soc., 44, 280-8 (1948). Am. SOC.Metals, “Metals Handbook,” 1948. Anderson, S., P h y s . Rev.,69, 52 (1945). Banks, F. N., Gas, 23, 12, 64 (1947). Benua, L. P., I r o n Age, 161,25,77-9 (1948) Booth, N., Davidge, P. C., Fuidge, G. H., and Pleasance, B., Gas W o r l d , 125, 720-1,730 (1946) ; 126, 146-50 (1947).
Brown, M. H., DeLong, W. B., and Auld, J. R., IND.EXG, CHEM.,39,839-44 (1947). Buell, C. K., andBoatright, R. G., Ibid., 39,695-705 (1947). Burghoff, H. L., and Blank, A. I., Proc. Am. SOC.Testing Mateiials, 28 (1948).
Camp, E. Q.,Proc. Am. Petroleum I n s t . , 27, No. 111, 153-66
.~.
11947). -. ,.
Campbell, W. E., and Thomas, U. B., T r a n s . Electrochem. Soc., 91, 623-39 (1947).
Collins, L. F., Power P l a n t Eng., 51, No. 12, 114-16, 132 (1947(. Cook, C. D., and Merritt, C., Jr., Chem. Eng., 54, No. 6, 77-80 (1947).
Cook, M., and Davis, E., T r a n s . Inst. Welding ( L o n d o n ) , 10, 178-92 (1947).
Dillinger, J. F., and Pattan, C. C., U.S . Patent 2,439,159 (April 6 , 1948).
Dlouhy, J. E., and Kott, A., Chem. Eng. Progress, 44, 399-404 (1948).
Fontana, M. G., and Zambrow, J. L,, Metal Progress, 53, No. 1, 97-101 (1948).
Froning, J. F., Richards, M. K., Stricklin, T. W., and Turnbull, S . G., I S D . ENG.CHEM., 39, 275-8 (1947). Gall, J. F., and Miller, €1, C., Ibid., 39, 262 (1947).
HARRY E. FISHER,
Vol. 40, No. 10
(20) Herbst, H. T., Light Metal A y e , 6, No. 1 and 2,20-4 (1948). (21) Hidnert, P., and Krider, H. S., J . Research Nail. B u r . Standards, 39, 419-21 (1947). (22) Hose, H., Welding Engr., 33, 51 (1948). (23) Hutchinson, T. S., and Reekie, J.. Naiure, 159,537-8 (1947). (24) Inglesent, H., and Storrow, J. A., I n d . Chemist, 23, 827-34 (1947). Metal I.,Progresa, 54, No. 1, 57(25) Jaffee, R. I., and Ramsey, R. € 63 (1948). (26) Keith, It. B., I r o n A g e , 161, No. 11, 160 (1948). (27) Kochendorfer, A., Metallforschung, 2, 173-86 (1947). (28) Kostenets, V. I., 9.Tech. P h y s . (U.S.S.R.),16,515-26 (1946). (29) Laird, A. W., and Maxson, G . I., U.9. Patent 2,417,558 (March 18, 1947). (30) Landau, R., and Rosen, R., IND.EXG.CHEX.,39, 281-6 (1947). i Lehrer, W., Metal Progress, 53, 393-402 (1948). 1 Marsel, C. J., and Allen, H. D., Chem. Eng., 54, No. 6, 104-8 (1947). Mitchell, N. W.,Corrosbn, 3, 243-51 (1947). Murray, R. L., Osborne, S. G., and Kiroher, M. S., IND.ENB‘ CHEM.,39, 249 (1947). Nowick, A. S., and Machlin, E. S., J . Applied Phys., 18, 79-87 (1947). Ohlmann, E. O., U. S. Patent 2,387,284 (Oct. 23, 1945). Palmatier, E. P., Chem. Eng. Progress, 44, 481-8 (1948). Pomfret, R. A., and Mosher, L. M., Corrosion, 4, No. 5 , 2 2 7 4 3 (1948). Priest, H. I?.? and Grosse, A. V., IND. ENG.CHEM.,39, 279-80 (1947). Priest. H. F., and Grosse, A. V., U. S. Patent 2,419,915 (1947). Ray, P. R., J. Chem. Education, 25,337-35 (1948). Seigle, L., and Brick, R. M., T r a n s . Am. Soc. Metals, Prepria$ 18 (1947). Simon, G., Electrowarme, 11,47-51 (1941). Stauffer, Iz. A,, Fox, K., and DiPietro, W. O., IND. ENC.CHEL. 40, $20-5 (1948). Tomashov, N. D., and Timonova, M. A., J. Phys. &‘hem, (U.S.S.R), 22, 221-31 (1948). Tracy, A. W., “Symposium on Atmospheric Exposure Tests QE Non-Ferrous Metals,” Am. SOC. Testing Materials, 1946. Uhlig, H. H., “Corrosion Handbook,” 1st ed., pp. 61-112, Ne& York, John Wiley & Sons, 1948. I b i d . , p. 567. Van Natten, W. J., I r o n A g e , 161, No. 2, 51-5 (1948). Van Royen, R. P., et al., Report of Copper Pipes Committee, Netherlands Water Works Assoc. (1946). Voce, E,, Metalluryia, 35, 205, 3-9 (1946). White, N. C., T r a n s . Electrochem. Soc., 92, 295-301 (1947). Wilkinson, E. R., Corrosion, 3, 252-62 (1947). Worrell, G. H., IJ. S. Patent 2,439,068 (April 6 , 1948). York, J. E., Heating and Ventilating, 45, 84-8 (1948). RECEIVED August 23, 1948.
U . S . Industrial
Chemicals, I n c , , New York, N . Y .
TEADY progress in elastomers has been made this past year, although there have been no spectacular advances; oftentimes what appear to be spectacular advances are only the results of years of steady progress. T o r k has been reported on the theoretical aspects of natural and synthetic rubbers, on new rubbers, new methods of compounding, and new materials of reinforcement. Considerable work was done on improving the properties of synthetic rubbers and the products made from them, and on the testing of rubber products, especially under simulated service conditions. Many of these advances are mentioned or described in more or less detail below.. THEORETICAL STUDIES
The effect of temperature on resilience has been studied with a new apparatus called a piezoelectric pendulum (68) and many new
data have been obtained on vulcanixates of several syntheticl rubbers as well as of natural rubber. An extension of the sta-# tistics of liquid-elastomer mixtures gives explicitly the sorptioh isotherm of gases in elastomers a t temperatures above theii critical temperatures (5). Isotherms of a number of vapors ic rubbers have also been calculated. The specific heat of unvulcanized rubber at 25’ 6.did not change when the rubber was stretched through the range of 0 t o 300% (51). On the other hand, the specific heat of vulcanized rubber, the stress iri which a t constant elongation increased linearly with rise in temperature, increased slightly with increase in elongation (0.002 calorie per gram per loo’%)? and the specific heats of other vulcanized rubbers at 25” C. did not change a t low elongations, but at approximately 200y0 elongation and above increased rapidly (0.015 to 0.020 calorie per gram per 100%). Relatively small, though technologically important, differences between
October 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY
thermal diffusivities are attributed to structural and chemical differences, and suggest that heat conductivity is determined mainly by chain-valence forces that are usually of the same general nature (64). With repeated stretching of loaded vulcanizates, there is progressive loss of stiffening, ultimately with little difference between the stress-strain curves of the loaded and unloaded vulcanizates a t elongations less than the previous elongation (67). Resistoflex B1003 (a polyvinyl alcohol), Resistoflex B1000, and Thiokol3000ST showed the lowest values of permeability to hydrocarbon gases (86).
stabilizer (10). The average particle size of over 2000 d. thus approachw that of the particles in natural latex, and the mechanical stability is much superior to that of natural latex. Hycar P.A. is an elastomeric polyacrylic ester resembling natural rubber, which retains its properties up to 400 a F., and is resistant to the action of ozone (39). Thiokol PR-1 is a relatively new polysulfide rubber with unusual resistance to solvents and useful from -60" to 212 O F . (71). Lactoprene-EV is a copolymer of ethyl acrylate and 2-chloroethyl vinyl ether (60). Its vulcanizates show outstanding resistance t o oils, oxidation, and heat.
+
GENERAL PROPERTIES
Vulcanizates of natural rubber, neoprene, and Butyl, at temperatures as low aa -20' F., became progressively stiffer with time, probably as a result of crystallization, whereas those of GR-S showed no such tendency (24). Tire tread mixtures of natural rubber and the corresponding vulcanizates stored for periods up t o ' 4 years showed very little change in propertia after vulcanization, whereas those vulcanized originally and then stored became poorer (62). Presence of the low molecular weight fraction of natural rubber and GR-S is more detrimental t o quality than any other fraction (40). Rubber covering of fabric is not an impermeable envelope, as in damp atmospheres the fibers absorb moisture ( 4 7 ) . Vinyl compounds can be copolymerized with natural rubber in the form of latex to give products useful in the preparation of molded, dipped, coated, and extruded articles ($9). I n static exposure to sunlight, sidewall vulcanizates containing waxes were superior, whereas in dynamic exposure to sunlight the vulcanizates containing no waxes were the more resistant (19). A review discusses the mechanical, physical, and chemical properties of rubber for mechanical engineers and indicates the need for additional data (83). NEW RUBBERS
Ordinarily natural rubber latex, after having been made acid with acetic acid, becomes coagulated in 1 to 6 hours, but if certain substances like the ammonium salts of long-chain fatty acids are added even in such a low proportion as 0.25010, coagulation takes place in 1 minute (60). This method allows the continuous preparation of crude sheet rubber. Low temperature copolymerization of butadiene and styrene a t 41" F. gives a GR-S rubber that is superior to the ordinary GR-S in tread wear with no sacrifice in resistance to cracking and cut growth, and furthermore is characterized also by excellent processing, particularly high tensile strength at normal and elevated temperatures, and high resilience (77). The cost of low temperature preparation is only about 0.25 cent more than €or standard GR-S (63). Copolymers of butadiene and isoprene with vinylpyridines give vulcanizates that show a high modulus and high tensile strength as compared with GR-S and a flexing-hysteresis balance that is for the most part superior to that of GR-S, although the hysteresis temperature rise is generally higher (22). Fluoroprene (2-fluoro-l,3-butadiene) copolymerized with acrylonitrile (3 to 20% of the total) gives rubberlike products of high resistance to oil and freezing (53). Elastomers with similar properties are also obtained by the copolymerization of fluoroprene, 15-80, with butadiene, 80-15, and styrene, 5% (26). A GR-S of low moisture absorption is prepared by coagulating highly diluted latex (less than 5% solids) with a dilute solution of alum (87). The product is approximately equivalent to deproteinized natural rubber in water absorption. Another method is to add a protective agent like glue and coagulate the latex in equipment of special design that allows a proper flow and mixture with air (49). Synthetic GR-S latex of high solids content (55 to 60%) is prepared directly in the reactor by varying the reaction rate through proper balance between emulisfier and
1789
NEOPRENE
Continuous isolation of neoprene is accomplished by coagulation on a freeze drum a t - 10' C. (98). This is the f i s t continuous coagulation of a dispersion by freezing. Extensive tests, including practical road tests of tires, have shown that both the serviceability and appearance of tires can be improved by the construction of tires a t least partially of neoprene (88). Neoprene carcasses show statistically longer life in service than natural rubber carcasses and neoprene treads show less tendency to crack, cut, and chip. SILICONE RUBBERS
The properties and applications of silicone rubbers have been reviewed (58), especially for engineering problems ($7). Inasmuch as silicone rubbers cold-flow a t high temperatures, they are used advantageously in the design and construction of stationary seals for high temperature oil lines (17). They are also used in wire-cloth reinforced belts in the food processing industries because they are odorless, tasteless, and nontoxic. Silicone rubbers adhere to properly prepared glass surfaces and coated glass fabrics are used as diaphragm materials in the processing industries and as electrical insulating tapes which are required to function continuously a t high temperatures. Silicone rubbers show remarkable resistance to heat and weathering (44), being still flexible after 50 days a t 302 O F. and retaining most of their properties after months of outdoor exposure to sunlight. The temperature resistance is improved by incorporating in the mix before curing one to two times the theoretical quantity of litharge necessary to react with the iron halide present ( 5 ) . Advantages of sponge made of silicone rubber are low cost and unchanging properties over a wide range of temperature ( 7 4 ) . A silicone type of adhesive that bonds silicone rubber to itself and to glass, metals, and ceramics remains flexible and resilient a t temperatures from -70" to 520" F. (69).
+
COMPOUNDING AND VULCANIZATION
In pure gum types of stocks containing magnesia or litharge and sulfur, inorganic oxidizing agents, particularly red lead, lead dioxide, ferric oxide, and lead chromate, accelerate the rate of vulcanization and increase the tensile strength, which is increased further up to 850 pounds per square inch by the addition of certain softening agents (30). Many data have been obtained on the effect of quantity of carbon black and softener on GR-S (84). Statex-K is a new furnace black of the quality of channel black in some of its properties and superior in others (8, 9). Natural rubber and GR-S mixtures containing it process more smoothly and economically and require less accelerator because of its high p H value. It gives better resistance t o heat and flexing as well as better aging properties. Frantex-A, a finely ground halloysite (hydrated aluminum silicate), is a new active filler with reinforoing properties so close to those of carbon black that H M F black can be replaced whoIly and EPC, MPC, and H P C blacks can be replaced partially by equal volumes and give approximately the same results (2,33).
1790
INDUSTRIAL A N D ENGINEERING CHEMISTRY
v31. 40, Ne. 10
plasticized with a highly halogeiiated saturated hydrocarbon and dissolved in a halogenated saturated hydrocarbon liquid solvent yields a nonflammable coating which will withstand the action of corrosive fluids and strong oxidizing acids (45). Studies are being made on vulcanizates of natural rubber, GR-8, and neoprene containing fungicides and their effect on the rubber when exposed to light, heat, oxygen a t 70" C., and soil burial (85). Copper naphthenate, as expected, had deleterious effects, and other fungicides showed little or no effect. ADHESIVES AND BOKDISG RUEBER TO AIETAL
Silicone Rubber Gasket Exposed to Chlorine at 220'
F.
KOdecrease in curing tinit: or change in quality of ihe rubber product occurs when a standard natural rubber compound is cured by radio-frequency treatment, as compared with the steam press cure of the same compound under similar conditions of temperature and time of cure (81). SOLVENT AND CORROSION RESISTAUCE
Unvulcanized natural and several types of synthetic rubber were tested as t o their solubilities in a great many organic substances (76). The solvent power and physical constants indicate the utility of a material as a softening agent or in cements. Furthermore, in general, materials that are good solvents for unvulcanized rubber are strong swelling agents for the same rubber vulcanized. The influence of structure on polymer-liquid interaction has been studied and the relation and absolute values of mvelling equilibria have been determined (7'5). Vulcanizates of GR-S containing IIMF black, acetylene black, and S R F black swelled less in hydrocarbons than did those containing >IT,lamp, and blPC blacks (66). When vulcanizates of natural and synthetic rubbers were allowed to s-,vell in r e p r o sentative liquids of a wide variety of chemical types, the results confirmed earlier work in shorsing that, in general, maximum swelling of a n elastomer in a liquid depends on the degree of similarity in structure of the elastomer and the liquid ( 6 7 ) . In the swelling of rubbers, a comparison was made of natural rubber vulcanized with different agents, and of the action of ethylenr glyrol on natural rubber, neoprene, and Perbunan vulcanizates (78). When the vulcanizates had the same hardness, the initial absorption of liquid wa3 practically independent of the agent used for vulcanization. At 25' C. the vulcaniTaies mentioned above did not swell appreciably in ethylene glycol, but a t 130"C. Perbunan swelled the least, and natural rubber and neoprene to about the same degree. A review of present developments and applications of rubber linings and coatings has been given (48). Rubber linings protect steel against corrosion and abrasion (83). Tank linings of soft natural rubber are protected against deterioration in hydrochloric acid solutions by formation of a hard rubber-hydrochloric acid surface film,whereas synthetic rubbers lack this property ( 4 3 ) . Keoprene is used as a tank lining where oil resistance and resistance to hydrofluoric acid are required. Halogenated rubber
"Engineering with Adhesives" ($5) tells a good deal aboul types and forms of adhesives and methods of application and testing. An adhesive that tenaciously bonds textile fibers tu vulcanized rubbers is prepared by treating natural rubber or polyisoprene in solution with an organic polyisocyanate; the cement formed is heated until a large drop in viscosity is obtained (90). This adhesive is said t o remain effective a t elevated temperatures in the presence of water. A cyclicized substituted pentadiene polymer, prepared from isobutylene and a polyolefin of 4 to 14 carbon atoms by treatment with a Friedel-Crafts catalyst in solution at --40" to 160" C., is dissolved in a volatile solvent and used for bonding rubber to metal walls (7). The Canite process for bonding rubber to metals consists essentially of interposing between the metal and the unvulcanized rubber two layers, one of chlorinated rubber and the other of a reaction product of acrylonitrile and natural rubber (18). The method of bonding rubber to mctal with Ty-Ply, characteristics of the bond under different conditions of service, and results of tests have been described (82). Esters of aliphatic and aromatic acids can be used to bond rubber to wire under heat and pressure ( l a ) . Similarly, a rubber-covered wire can be protected by a n overlayer of neoprene bonded by means of a thin film of an ester, the neoprene protecting the rubber from the action of oils, grease, and sunlight ( 1 3 ) . NEW RESINS AND THEIR USES IN CO3ZPOUNDIN6
Polybutadiene is a rubber, polystyrene ii; a resin, and the copolymer of butadiene and styrene in the ratio of 78 to 22 is GR-S. The copolymer of butadiene and styrene in the ratio of 10 to 90 is a tough rubbery resin, which when mixed with natural rubber or GR-S and compounded and vulcanized, has very interesting characteristics ($1, 41). I n the first place, it acts like a reinforcing agent-somewhat like carbon black. It improves processing, reduces shrinkage before vulcanization and cold flow after vulcanization, improves the tensile strength and resistance to tearing, increases hardness and stiffness without resulting brittleness, gives exceptional resistance t o flex-rracking a t low temperatures, imparts high resistance to abrasion, and has good aging properties. It is useful for making light colored products of l o x density. It can be obtained in the form of a latex, in which form it is useful in mixing with rubber latexes to impart these interesting properties (911Phenolic iesins can also be mixed with natural and synthetic rubbers, and they give products that have increased hardness and stiffness, resistance to abrasion, solvents, and oils, good aging, and improved surface finish (80). These resins are particuarly useful in the niirile rubbers (53). Polyvinyl chloride a i d the nitrile rubber, Hycar, form the Geon-Hycar Polyblends (55). S-Polymer is a new type of thermoplastic resinous polymer formed by copolymerizing styrene and isobutylene by a low temperature process similar t o that used in the manufacture of Butyl rubber ( 1 4 ) . These polymers are plastic, yet rubberlike in some respects, particularly in extensibility and recovery. Wnen combined with natural and synthetic elastomers, they improve the processability. decrease water and gas absorption, and modify other physical properties.
October 1948
INDUSTRIAL AND ENGINEERING CHEMISTRY METHODS OF TESTING
Methods of testing are of wide interest and accordingly a number of them are given t o indicate the trends of the work in this important field. Recent developments in methods of determining the absorption of energy by rubber are of promise (66). The qualitative analysis of mixtures of elastomers, the quantitative analysis of mixtures of natural rubber and GR-S, and the determination of the nitrile content of nitrile rubbers can be made by infrared spectroscopy, with an accuracy of about 1% average error (16). Studies have been made on methods of determining tear resistance (6466)on the condition of the surface in the ball-indent* tion test for hardness (16), and on the influence of the thickness of the rubber in tests for hardness with various identors (79). No significant improvement in the degree of correlation of laboratory and service abrasive tests of rubber tire treads has been made since 1931, and limitations with respect to variations in compounding are still essentially the same (48). I n tests for flexcracking resistance, it is essential to improve the methods (61) and the uniformity of the test specimens (6.9). The bursting strength of rubber specimens is tested by a n instantaneous burst and a time burst ( 6 ) . Ordinary stress-strain relationships as found by tensile strength tests are not found in the burst test, as neither suitable means for the measurement of deformation as a function of pressure nor the ideal type of specimen holder has been devised. Time-bursting pressure data give a n indication of the ability of the material to withstand a sustained load. The chemical composition of the monomer is the governing factor in the behavior of the polymer at low temperatures. The stiffness of elastomers that are capable of crystallization-e.g., Hevea (natural) rubber, neoprene, and Butyl rubber-depends not only on the temperature but also on the time at the low temperature (8s). A new laboratory test has been developed. I n the electrical testing of soft rubber, tin-foil electrodes are the best to use ( 4 ) . All determinations can be made within 15 minutes from the application of the electrodes, and changes caused by atmospheric conditions are minimized. An apparatus and the techniques for measuring various properties of rubber torsion springs of importance in the performance and life of such springs have been described and illustrated (11).
NEW PRODUCTS AND USES
New products may not mean much in themselves for the moment but they usually suggest other new applications. Therefore, a selected list is given. I n resilient products composed of latex bonded fibers, maximum resilience is obtained by using strongly curled fibers with the greater proportion of the rubber localized at the points of intersection (1). An article on “Engineering with Rubber” consists of a review and discussion of the use of rubber in motor mountings and of the importance of research in developing improved types of rubber (46). A new type of impact cushioning idler for belt conveyers (88) is nonpneumatic and consists of rubber rings mounted on the idler core instead of the conventional rubber-covered steel idler. Maximum deflection is about six times greater than with the conventional idler. The author of a n article on “Engineering with Sponge Rubber” discusses methods of using sponge rubber for solving sealing or cushioning problems, especially in automobiles, and includes diagrams and methods of testing (9.8). The new “Highway Traveler,” a deluxe 50-passenger compartment coach recently introduced by the Greyhound Corporation, has new safety features consisting of wire cord tires arid newly perfected crashproof gasoline tanks t h a t have many of the features of the self-sealing fuel. cell used in combat planes during the war (78).
1791
A new glass cord steam hose has been developed that will carry saturated steam at a temperature of 388” F. at a pressure of 200 pounds (70). It utilizes rubber-covered Fiberglas cords which are 0.025 inch in diameter and result in a wall only g / ~ inch in thickness. A new hydraulic hose for airplanes t h a t withstands 3000 pounds working pressure is used on some of the newest large planes (86). It must handle the sudden surge of hydraulic power which operates landing gears, flaps, and other mechanical devices. Special steel wire with a tensile strength of more than 400,000 pounds per square inch is used in the construction of the hose. An improved check valve has a tough flexible tubular operating member of synthetic rubber with a thick load section t h a t tapers down to a sensitive operating lip which requires no differential pressure to effect positive bubble-tight shutoff (SO). This tapered synthetic rubber lip can readily expand to permit unrestricted streamline flow. The degree to which i t opens or closes is in direct ratio to the flow volume. A heating pad for the inside surface of the jet cowl on an experimental plane is now under test (68). There are possibilities of using heated rubber as a protector against icing. Data have been published on the use of Uskon radiant heating panels which generate heat in the ceiling of homes (72). They are heated by a conductive rubber resistance element and make possible the efficient and economical heating of homes with electrcity. There are no wires in the heated area of the panel but wires bring current to the edge of the conductive rubber. Pliotherm heating units are also available for similar uses (88). A pulley belt designed to prevent slipping has rubber teeth and is strong, highly flexible, and virtually noiseless in operation (31). It is designed for use on machinery equipped with special pulleys that are grooved to fit the teeth. It is reinforced with steel cables expbedded in oil-resisting synthetic rubber. The cables reduce stretch almost to zero, eliminating the necessity of take-up devices t o remove any slack. Aluminum bore hole and mine entrance cables permit a 30 to 50y0 saving in cost and a 50% saving in weight over equivalent copper cables (34). The cables are covered with a neoprene compound which resists mine acids and oils and, because of their lighter weight, can be handled readily without the need of elaborate equipment. A rubber propeller with a cast aluminum or bronze core is now being manufactured for outboard motors (86). The rubber propeller is stiff enough to cut the water, yet sufficiently resilient to slide over weeds without being fouled and to bounce over driftwood and other obstacles without shearing the drive shaft pin. The British have published a book on “Rubber in Engineering,” baaed on research carried out under government auspices (87), which contains information on the fundamental properties of rubber, rubber technology, and principles of the design of rubber engineering components. LITERATURE CITED
(1) Appleton, L., Truns.Inst. Rubberlnd., 23,41-5 (1948). (2) Augustin, S.,Rev. g h . caoutchouc, 25,20-4,56-62,85-90(1948). (3) Barrer, R.M.,Trans. Faraday Soc., 43,3-11 (1947). (4) Bonner, R.,Trans. Inst. Rubberlnd., 23,155-61 (1948). (5) British Thompson-Houston Co., Ltd., British Patent 594,506 (Nov. 12, 1947). (6) Bryant, A,, Am. SOC.Testing Materiu7.s Bull. 148,64-8 (1947). (7) Calfee, J. D.,and Young, D. W. (to Standard Oil Development Co.), U. 9. Patent 2,423,755(July 8, 1947). (8) Carr, R.L., Rubber A g e ( N . Y . ) ,61,66-7(1947). (9) Carr, R.L.,and Wiegand, W. B., I n d i a Rubber W o r l d , 116,205-7 (1947).
(10) Ch&&den, F. D.,McCleary, C. D., and Smith, H. S., IND. ENQ.CHEM.,40,337-9 (1948). (11) Cornell, D.H.,and Beatty, J. R., Rubber Age ( N . Y.), 60,67988 (1947). (12) Cox, T. K. (to Western Electric Co.), U. S. Patent 2,427,196 (Sept. 9,1947).
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17-92
INDUSTRIAL AND EN
(13) Ibid., 2,427,197 (Sept. 9, 1947). (14) Cunningham, E. N., Rubber Age (Ar. Y.), 62, 187-90 (1947). (15) Dinsmore, H. L., and Smith, D. C., A n a l . Chem., 20, 11-24 (1948). (16) Dock, E. H., and Scott, J. R., J . Rubber Research, 16, 134-49 (1947). ENG.CHEX, 39, 1372-5 (17) Doede, C. M., and Panagrossi, A., IND. (1947). (18) Duval, J. G., and Gossot, J., Chimie & Industrie, 57, 540-7 (1947). (19) Fielding, J. H., I n d i a Rubber W o r l d , 115,802-5 (1947). (20) Fisher, H. L., and Davis, A. R., IND.EM+.CHEM.,40, 143-50 (1948). (21) Fox, K. M., I n d i a R u b b e r W o r l d , 117,487-91 (1948). (22) Frank, R. L., Adams, C. E., Blegen, J. R., Smith, P. V., Juve, A. E., Schroeder, C . H., and Goff, M. M., IND. ENO.CHEX., 40. 879 (1948). (23) Gehman, S.‘D., iVoodford, D. E., and Wilkinson, C. S., Jr., Ibid., 39, 1108-15 (1947). (24) Gregory, J. B., I n d i a Rubber W o r l d , 117, 611-16 (1948). (25) Hendrichs, J. O., Lindner, G. F., and Wehmer, F. J., Rubber A g e ( N . Y . ) ,63, 327 (1948). (26) Hill, F. B., Jr, (to E . I. du PonL de Nemours & Co.), U. 8 . Patent 2,435,213 (Feb. 17, 1948). (27) Imperial Chemical Industries, Ltd., “Rubber in Engineering,” Brooklyn, N. Y., Chemical Publishing Co., 1946. (28) I n d i a Rubber W o r l d , 117, 523 (1948). (29) Ibid., p. 628. (30) Ibid., 118, 65 (1948). (31) Ibid., pp. 218, 275. (32) Ibid., p. 260. (33) Ibid., p. 279. (34) Ibid., p. 393. (35) Ibid., p. 396. (36) Ibid., p. 416. (37) Irby, C. S., Jr., Goss, W., and Pyle, J. J., Ibid., 117, 605-8, 616 (1948). (38) Irish, E. M.. and Stirrat, J*R., Product Eng., 18, No. 2, 146-7 (1947). (39) Jacobson, R. A. (to E. I. du Pont de Nemours & Co.), U. S. Patent 2,422,550 (June 17, 1947). (40) Johnson, €3. L., IND. ENQ.CHEM.,40,351-6 (194b). (41) Jones, M. E., and Pratt, D. M., I n d i a Rubber W o r l d , 117, 609-10 (1948). (42) Ju;e,-A.’E., Fielding, J. H., and Graves, F. L., Am. Soc. Testing Materials BulE. 146, 77-9 (1947). (43) Klein, H. C., Proc. Am. Electroplaters’ SOC.,1946, 144-51. (44) Konkle, G. M., Selfridge, R. R., and Servais, P. C., IND. ENG. CHEM.,39, 1410-13 (1947). (45) Large, C. B., Zucrow, M. J., and Hirch, R. J. (to Aerojet Engineering Corp.), U. S. Patent 2,426,512 (Aug. 12,1947). (46) Lawrie, J. P., Rubber Deuebpments, 1, No. 1, 12-18 (1947). (47) Lyons, W. J., Ziifle, H. M., Nelson, M. L., and Mares, T., I n d i a Rubber W o r l d , 116,199-204,207 (1947). (48) McNeill, J. J., Corrosion and Material Protection, 4, No. 2, 13-14 (1947). (49) Madigan, J. C., Borg, E. L., Provost, R. L., Mueller, W. J., and Glasgow, G. U., IND. ENG.CHEM., 40,307-11 (1948). (50) Mast, W. C., and Fisher, C. H., Ibid., 40, 107-12 (1948). (51) Mayor, And& Experienfia,3, No. 1,26-7 (1947).
N E E R I N G CHEMISTRY
VOl. 40, No. 10
(52) Moakes, R. C. W., and Soden, A. L., J . Rubber Research, 17,30-2 (1948). (53) Mochel, W. E. (to E. I. du Pont de h‘emours & Co.), U. S. Patent 2,429,838 (Oct. 28, 1947). (54) Morris, R. E., and Bonnar, R. U., A n a l . Chem., 19,436-8 (1947) (55) Moulton, M. S., I n d i a R u b b e r W o r l d , 116, 371-3 (1947). (56) Mullins, L., J . Rubber Research, 16, 180-5 (1947). (57) Ibid., pp. 275-89. (58) Mullins, L., Trans. I n s t . Rubberlnd., 22, 235-65 (1947). (59) Newberg, R. G., Young, D. W., and Fairclough, W. A , Rubber Age ( N . Y . ) ,62, 533-9 (1948). (60) Newton, E. B., Stewart, We D., and Willson, E. A., IND.ENG. CHEY.,39, 978-84 (1947). (61) Newton, R. G., J . Rubber Research, 16, 237-44 (1947). (62) Newton, R. G., and Scott, J, R., Ibid., 16, 245-61 (1947). (63) Rannels, K., Automotive and Aviation Inds., 98, No. 7, 25 (1948). (64) Rehner, J., Jr., J . Polymer Sci., 2, 263-74 (1947). (65) Reinsmith, G., I n d i a Rubber W o r l d , 116, 499-503,507 (1947). (66) Rostler, F. S., and Morris, R. E., Rubber Age (V.Y . ) , 61, 59-62 (1947). (67) Rostler, I?. S., and White, E. M . , Rubber Age ( X . Y . ) ,61, 313-21 (1947). (68) Rubber Age ( N - Y.), 62, 559 (1948). (59) Ibid., p. 561. (70) Ibid., p. 570. (71) Ibid., p. 579. (72) Ibid., 63, 56 (1948). (73) Ibid., p. 222. (74) Ibid., p. 228. (75) Salomon, G., and van Amerongen, G. J., J . Polymer Sci., 2, 35570 (1947). (76) Sarbach, D. V., and Garvey, B. S.,Jr., I n d i a Rubber W o r l d , 115, 798-801 (1947). (77) Schulse, W. A., Reynolds, W. B., Fryling, C. F., Sperberp, I;. R., and ‘I’royan,J. E., Ibid.,117, 739-42 (1948). (78) Scott, J. R., J . RubberResearch, 16,213-36 (1947). (79) Ibid., 17, 1-7 (1948). (80) Searer, J. C., Rubber Age ( N . Y.), 62, 191-3 (1947). (81) Sharbaugh, A. H., IND. ENQ.CHEM.,40,1254-8 (1948). (82) Shattuck, R., Rubber Age (N. Y . ) ,61,451-4 (1947). (83) Smith, J. F. D., iMech. Eng., 70, No. 2, 118-22 (1948). (84) Sperberg, L. R., Bliss, L. 9.,and Svetlik, J. F., IXD. ENQ.@HEM., 39, 511-14 (1947). (85) Stief, J. L., Jr., and Boyle, J. J., Ibid., 39, 1136-8 (1947). (86) Stout, L. E., Geisman, R., and Mozley, J. M., Jr., Chem. Eng. Progress, 44, No. 3, T r a n s . Am. I n s t . Chem. Engrs., 219-28 I
(1948).
(87) Ten-Bioeck, W.T. L., and Juve, R. D., I n d i a Rubber W o r l d , 116,781-2 (1947). (88) Torrence, M.F., Rubber A g e ( W . Y . ) ,61, 63-6 (1947). (89) True, 0. S., Product Eng., 18, No. 1, 142-8 (1947). (90) Verbanc, J. J. (to E. I. du Pont de Nemours & Go.), U. 8. Patent 2,417,792 (March 18, 1947). (91) Wcatherford, J. A,, and Xnapp, F. J., I n d i a Rubber W o r l d , 117, 743-4, 748 (1948). (92) Yoran, C. S., Rubber A g e ( N . Y.),63, 199 (1948). (93) Youker, M. A., Chem. E n g . Progress, 43, No. 8, Trans. Am. Inst. Chem. Engrs., 391-8 (1947). RECEIVED August 2, 1948.
COURTESY MYCAILEX CORPORATION OF AMERICA
Glass-Bonded Mica Parts 4. Insulator for eleotrical instrument
5, 6. Hermtic seal, crystal housing
7. Insulator, automobile antenna -__
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