PLASTI Cis - ACS Publications

ethylene bottles and film are providing a light-weight shatterproof, and corrosion- resistant packing medium. Hoods, ducts, tanks, piping, and fitting...
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P L A S T I C"-i s G . M. KLINE, National Bureau of Standards, Washington, D. C. R. €3. SEYMO'ISR, Atlas Mineral Products Co., Mertstown, Pa. under the trade names Agiline, Ampcoflex, Boltaron, and Lucoflex (79). Rigid polyvinyl chloride pipe may be threaded and connected with appropriate molded fittings or joined with adhesives or by welding (106, 121, 158). Specific techniques for repairing laboratory hoods and welding of plastics have been reported. Considerable information has also been published on physical and chemical properties and uses of rigid polyvinyl chloride structures (13, 30,166,164,166,172). Products made from vinyl plastisols, organosols, and solutions by methods ranging from slush molding and injection molding to casting, dipping, and spreading include plating racks, tool handles. safety clothing, and floor coverings (10, 6%,99,128). The utilization of these materials has been increased through the addition of gelling agents to form plastigels (131). Vinyl plastics continue to be used in large volume as strippable plastics (141 1. Vinyl chloride plastics have been advocated as the base for anticorrosion tape for service pipes (12), as protective coatings (3, 42), as a sealing cement for the repair of vinyl plastics, and as an additive to portland cement to produce a somewhat resilient nondusting concrete (33).

T h e increasing utilization of plastics in the chemical engineering field has been a significant factor in the 60% growth in production of plastics since 1949. Polyethylene bottles and film are providing a light-weight shatterproof, and corrosionresistant packing medium. Hoods, ducts, tanks, piping, and fittings made of unplasticized polyvinyl chloride are now available from at least four firms in this country. A tough construction material made of glass fibers and polyester resins has proved to be eminently satisfactoryfor tanks, pipe, and other parts of chemical plant equipment. New plastic materials that are helping to meet the corrosion problems of the chemical industry are epoxy resins, acrylonitrilecopolymers,polymethyl alpha-chloroacrylate, and styrene-butadiene copolymers and blends.

T

HE production of materials classified by the United States

Tariff Commission as plastics and resin materials was 2.4 billion pounds in 1951, compared to 1.5 billion pounds in 1949 reported in the last article in this series ( 6 7 ) . This total includes 470,000,000 pounds of phenolics, 240,000,000 pounds of urea and melamine resins, 400,000,000 pounds of styrene polymers and eopolymers, 480,000,000 pounds of vinyls, 430,000,000 pounds of alkyds, and 180,000,000 pounds of coumarone-indene resins. A significant factor in this rapid growth of the plastics industry is the increasing utilization of these materials for industrial purposes, especially in the chemical engineering field. ETHYLENE POLYMERS

The new polyethylene plants that have come into production recently have boosted the available capacity for this material to 85,000,000 pounds, and additional facilities are expected to be ready in 1953. The polyethylene squeeze bottle has been accepted for packaging spray, pharmaceutical, and facial preparations because of its nonbreakability, light weight, and self-dispensing features which offset its higher cost compared to glass (96, 119). Polyethylene film is &ding many applications in the packaging (26) and chemical (46, 78) industries. Polyethylene has been used successfully as a flame-sprayed coating for chemical apparatus (38, 116, 117, 178). Recent initiation of production of extruded polyethylene monofilaments for the textile industry offers promise of opening up other large-volume markets for this polymer (193). Polytetrafluoroethylene and polymonochlorotrifluoroethylene products continue to be of increasing interest for chemical applications requiring inertness, high temperature resistance, and stable electrical properties (35, 43, 60, 61, 53, 76, 136, 139, 176).

POLYESTERS

VINYL POLYMERS AND COPOLYMERS

The vinyl resins continued to expand into new fields. unplasticized polyvinyl chloride is superior t o the plasticized product in heat and resistance, electrical properties, and of mechanical strength. It is well suited for the manufacture chemical plant equipment, photographic trays, piping, sheeting, films, bristles, and fibers (9, 20, 102, 109, 1222, 1223, 126, 127). Rigid vinyl structures under the name of Vinidur have been used for many years in Germany (118). In this process, calendered sheets are laminated to form thick rigid polyvinyl chloride sheets which are drawn or welded to form hoods, ducts, and tanks. These techniques have also been adopted by the chemical processing industry in other parts of the continent (104). At least four American plastic manufacturers are producing polyvinyl chloride resins that can be extruded or calendered and laminated similar to Vinidur. Rigid vinyl parts are available in this country

The unsaturated polyester resins, which cure by polymerization due to the carbon double bonds present, have made further advances in the molding and laminating fields. The molding compound owes most of its increasing acceptance to high-speed cure, low-cost molding requirements, excellent electrical properties, high heat resistance, dimensional stability, and low water absorption (28, 106). Strength retention under wet conditions and a t temperatures up to 500" F. is now possible for glass fiber laminates prepared with improved finishes on the fiber ( 5 , 8 ) and polyester resins based on triallyl cyanurate (27, 32). The properties and applications of polyesters in casting and laminating were reviewed ( 6 , 31, 68,192, 196). Techniques for the continuous production of polyester pipe (111) and improved methods for the manufacture of polyester tanks (108) have been described. The potentialities of these resins for use with glass fiber reinforcement in the production of machine housings, fuel tanks, lockers, and other parts requiring a high degree of toughness are well known. They should have many applications in the chemical engineering field, particularly where toughness, lightness in weight, and numbers Of large Parts are needed. In addition, they may be able to establish themselves in markets opening UP 8s a result of shortages of various metals for

NYLON RESINS

The use of this plastic for molding gears, cams, bearings, and other machinery parts where toughness and abrasion resistance are important is a new development since World War 11. The experience and research that have led to their adoption in business machines, food mixers, speedometers, textile machinery, aircraft rotor transmissions, temperature-control equipment, avashing machines, and door locks should provide the basis for obtaining proper design and performance in this new field (40,132). In ad-

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INDUSTRIAL AND ENGINEERING CHEMISTRY

Vol. 44, No. 10

Tanks for Carrj-ing Fuel and Water across Saudi Arabian Deserts Tanks used by Arabian American Oil Co. are made of American Cyanamid’s Laminac polyester resin reinforced with OwensCorning’s Fiberglas mat

dition to reports on applications oi nylon resin suspensoids (196), new information has been published on their stability ( 1 ). PHENOLIC AND FURAN RESINS

Two new applications of phenolic resins offer great promise for further increases in their consumption. One of these is their use as a binder to the extent of 6 to 10% by weight with sand to produce molds for casting metal parts in foundries. The phenolicsand mold results in improved quality of castings, reduction in manual labor and floor space required, lower cost, and improved working conditions in the foundry (90). The other new market is in resin-sawdust products in which approximately 7% of phenolic resin serves as the binder. Molded panels 4 feet square are used in the production of doors, drawer bottoms, cabinet ends and backs, and various furniture items ( S 6 , 94). New developments in phenolic casting resins are of interest for defense tooling and chemical plant equipment (86). Phenolic plastics containing chopped nylon yarn were reported to have good electrical properties and dimensional stability under myet conditions (41). The properties and applications of a variety of phenolaldehyde resins were described (39, 86,103,130). The chemical resistance of furan and phenolic plastics has been investigated further (167, 168, 169, 171). Linings based on glassfiber-reinforced furan resins have been discussed (65). A survey (134) has been made on the use of furfural in plastics and new casting techniques for the industrial casting of phenolic resins have been described (110). SILICONE POLYMERS

Silicone resins and rubbers are extremely useful for engineering applications involving abnormally high or low operating temperatures, as in automotive and aircraft engines and structures (lS7, 148). Additional information has been published on the use

of silicones or blends of silicones and alkyds for corrdsion resistance a t elevated temperatures ( 1 4 , 16, 18, 24). According t o Leavenworth (E?),silicones with metal fillers are satisfactory a t temperatures up to 1000° F. Tyner (191)has reviewed the use of silicones as agents for the prevention of settling, flooding, and foaming. Many commercial r~ater-repellentformulations containing silicones (19) and specialized silicone rubbers (143) are now available. Several reviews on silicones have also appeared ( 7 , 49, 76, 7 7 ) . STYRENE POLYMERS A N D COPOLYMERS

It is to be expected that polystyrene and more parti~ularly~the tough materials prepared from the styrene-butadiene copolymers of high styrene content (116) will find many significant uses in chemical engineering equipment in view of the approaching dominant position of styrene plastics among thermoplastics. Recent progress in polystyrene molding materials has been marked by the introduction of lubricants, extension of the color range, and improvement in heat resistance through reduction in content of monomer and low molecular weight polymer. The better flow properties and improved molding techniques have made possible such large moldings as the 34-ounce refrigerator hydrator, 59ounce television lens, and 150-ounce aircraft battery case (37, Si). Blends of styrene-acrylonitrile copolymers with butadieneacrylonitrile rubbers are neither weldable nor flame-sprayable but have been extruded to form pipe and molded to form equipment for the chemical processing industry (16). Evaluation of experimental styrenated alkyds in clear films and in white enamels indicated that they have superior drying time and chemical resistance to conventional phthalic alkyds. It appears certain that styrenated alkyds will play an important role in the surface coating industry from both economic and performance considerations (47).

INDUSTRIAL AND ENGINEERING CHEMISTRY

October 1952

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OTHER POLYMERS

*

Acrylonitrile is becoming of increasing significance in the production of polymers, either alone or copolymerized with vinyl chloride or styrene. The most promising outlet a t present is in synthetic fibers (Orlon and dynel). The synthetic elastomer made with acrylonitrile and butadiene also serves as a plasticizer for polyvinyl chloride (17). The epoxy resins found unexpected uses as stabilizers in chlorine-containing plastics and in the manufacture of shock-resistant phenolic molding compounds as well as in coatings, adhesives, laminates, and potting compounds (115, 189, 174). Another transparent plastic came closer to commercial availability as two companies, Arnold, Hoffman & Co., Inc., and General Aniline and Film Corp., undertook the production on an experimental scale of polymethyl alpha-chloroacrylate (called Gafite by the latter firm). The soitening point, heat distortion temperature, tensile strength, and hardness are higher than those of polymethyl methacrylate. Its greater flame and crazing resistance are advantageous in glazing applications (177). The availability of a hot- and cold-water-soluble derivative of cellulose-sodium cellulose sulfate-in experimental quantities was announced by the Tennessee Eastman Co. Films prepared from this compound are colorless, transparent, strong, flexible, and oil-resistant. Other potential applications are based on its suspending, thickening, and stabilizing properties (190). Tentative specifications for plasticized sulfur compositions have been proposed (4) and the effect of composition on various properties of plasticized sulfur cements has been investigated (63, 166). The effects of chemicals on plasticized sulfur at various temperatures have been reported (170). LAMINATES AND SANDWICH MATERIALS

The successful bonding of metal foils t o many grades of laminates has resulted in ever-widening use of printed circuits, which replace conventional wiring, resistors, capacitors, and inductances in electronic e q u i p m e n t (179). Laminated cylinders up to 90 inches in diameter, 4 inches in wall thickness, and 150 inches in length are now being made for use in power transformers (194). The properties and industrial applications of laminates made with various fabrics and resins were reported (89, 34, 36, 58, 93, 124). Honeycomb cores for sandwich structural materials are now being made by seven manufacturers with reinforcements of paper, cotton fabric, glass cloth, and aluminum foil. The principal uses for the honeycomb sandwiches are aircraft parts, walls and doors for houses and factories, and shipping containers. One manufacturer predicts their use for a t least 40% of new aircraft frame weight by 1956 (98).

Processing Tank Hood for Chemical Plant to Handle Sulfuric Acid Mist Built up from sheets of Uscolite, styrene rubber wpolymer. pieces and ribs are extruded from same material

Corner

These products combine high strength with ready fabrication and transportability and should find important applications in the chemical engineering field. The growing importance of sandwich materials was emphasized in a series of reports dealing with their testing, evaluation, and use (48, 61, 183). The demand for polystyrene foamed plastic in display and packaging items exceeds the present production capacity. Expansion of its markets into the low t e m p e r a t u r e insulation, sandwich construction, and flotation fields as well as the development of similar outlets for phenolic, vinyl, urea, cellulose acetate, polyurethane, and other plastic foams is still t o come (80). RESISTANCE TO CHEMICALS

The effect of sodium hydroxide (44), sulfuric acid (173), hydrogen peroxide (73, 155),hydrofluoric acid ( I % ) , ethyl alcohol (74,156, 188), sulfur (69, 16.4, 187), ferric chloride (68,161,184)> hydrocarbon solvents (71, 152,185), copper sulfate(67, 150, 183), citric acid (66, 149, 182), chromic acid (70, 148, 181), and phenol (79, 153, 186)on various plastics has been reviewed. APPLICATIONS

Clear Butyrate Plastic Line for Flow of Wine Wine flows from large etorage vat (not shown) through rubber hose being coupled to metal fixture and up throu h dear butyrate (Tenite 11) line t o tax payment tank anif bottling room

A major trend in the chemical industry is the use of plastics in the construction of corrosion-resistant equipment; added impetus in the direction is furnished by the present shortage of

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INDUSTRIAL AND ENGINEERING CHEMISTRY

Val. 44, No. 10

cussed the ube of plastics in 3ulfate arid -tlrmchPmical pulp mille, I espectively.

Corrosion problems i i i c ~ e : ~ t ba5 e the chemical industry piogresses. Problems heretofore considei ed unsolvable are now being solved through the intelligent use of plastics. Cooperative efforts between plastics technologists and corrosion engineers are bringing about advances M hich are mutually beneficial t o plastic manufacturers and to the industry plagued n ith rori osion problems. \CK \io& LEDG\IE.\'I

The authors gratefullj nckriowledge the assistance oi A l i r 1. G. Callomon, National Bureau of Stanctnrd-, arid .Jean D. Fenatermacher, The Atlas \lliir~ialProdur t q ("o of the bibliography

in t h e prepaintjor

L I ' I ' h K \ I I H h CIIEIJ

Piping Extruded from Geon 404 Piping can be threaded by standard pipe dies and equipped with acidresisting plastic tees, 90 elbows, 45 elbows, companion flanges, blind flanges, couplings, reducing couplings, and caps

steel, copper, aluminum, and other metals. Tanks, hoods, vats, duct systems, and the like are being fabricated of a blend of high styrene resin and acrylonitrile rubber (100) and rigid polyvinyl chloride (60). Chemical-resistant containers are made of polyethylene (98),cellulose acetate (@), and acrylic and styrene resink (89),and pumps of urea-formaldehyde resins (85)and polyethylene (101). Acid- and alkaliproof cements or mortars based on furfuryl alcohol resins are used in laying brick tank linings and floor8 in chemical plants (88, 17'5). Protective clothing to guard personnel against hazardous chemicals is coated Tiith polyvinyl chloride ( l a b ) . Specialty applications of plastics, based on their chemical resistance, include armored vinyl tubing for beverages and gases (91), phenolic parts for a vegetable peeler (97), vinyl coatings for refinery equipment (113') and baking trays ( 8 7 ) , a vinyl film cover for soil fumigation (95),and linings for electroplating tanks (21). A noteworthy report dealt with the susceptibility of plastics to contamination .rvith radioactive compounds and their subsequent ease of decontamination (189). Ion exchange resins continued to take on new industrial jobs in such operations as water softening and purification; production of drugs, sugar, and various food products; recovery of metals; and separation of rare earth elements (56). Essentials required for the proper selection of protective coatings for resistance t o fumes have been tabulated ( 4 5 ) and the techniques required for the application of various plastic coatings have been outlined ( 2 , 159). Xei5- uses of plastics for the repair and construction of corrosion-resistant floors have been described (158, 160, 161). Highly conductive plastics ( 2 2 ) and plastics having controlled electrical resistance in order to minimize explosive hazards in hospital operating floors have been introduced. A new plastic joint for vitrified clay pipe consisting of a vinyl plastisol male threaded end with a molded phenolic female coupling (107) and a nen- hot-melt compounded hydrocarbon plastic jointing material have been developed (167). Kammermeyer (64) has surveyed the use of plastics in the chemical industry. The criteria for the selection of plastic materials in sewage and waste treatment plants have been listed (64, 1.40). Considerable emphasis has been placed on the use of plastics for protection of submerged wellheads (55),for vessel linings (11), and for general use in the petroleum industry (25, 120, 168). Corrosion problems continue to plague the paper industry. A study has been undertaken to screen commercial furan resins for use a t elevated temperatures in the sulfate process. The effects of alkaline pulping (147),acid pulping ( I & ) , bleaching (146, 180), and stock handling (144) on various construction-type plastics have been reported. Collins ( 2 3 ) and Rlurtfeldt (11.4) have dis-

Achhammer, B. G., Reinhart, P. IT-., arid Kline, G. M., J . lie>search S a t l . Bu.r. Staizdards, 46, 391 (1951). Slexander, A. L., E k e . M f g . , 49, 112 (Febrimry 1952). Am. h i l d e i . , 74,202 (February 1951 j, A S T M B u Z l . , KO.181, 1.2 (1952). Bacon, C. E., Modern Plastics, 29, 126 (July 1962), Bacon, C. E., and Sonneborn, R. H.. I n d i a Rubber ).r70/,kl, 125, 323 (1951). Bartlett, G., Gen. Elec. Kev., 54, 58 (January 1951). Rjorksten, J., and Yaeger, L. I,.,M o d e r n Plastics, 29, 124 (Jul?1952). Brit. Plastics, 24,407 (1951). Ibid., 25,3 (1952). Carpenter, G. C., Petioleum fiefiner, 29, 1x0.7, 95 (1950). Carter, G. M., Gas A g e , 106, 42 (Nov. 23, 1950). Charity, F., Am. Machinist, 95, 164 (Nov. 12, 1951) Chem. Age (London), 65, 160 (Aug. 4, 1951). Ch.em. Eng., 57, No. 6,166 (1950). Ibid., 58, No. 4, 162 (1951). Chem. Inds., 66,345 (March 1950). Ch.em. I n d . W e e k , 68, 18 (Jan. 20, 1951:. Chcm. Week, 69,35 (Sept. 29, 1.951). Ibid., 69,37 (Kov. 17, 1951). Colegate, G. T., Chenz. Eng., 31, 448 (1950), Coler, M. il., Barnet, F. R., Lightbody, h.,and Perry, -1. A , , Jr., Proc. I n s t . Radio Engrs., 38, KO.2, 117 (1960). Collins, T. T., Paper Trade J . , 130, No. 21, 32; S o . 22, 262 (1950). Cook, G. S., and Kennedy, D. K , T a n , Paint and Vawtiah Mag., 25,34 (December 1961). Cook, W. B., Corrosion, 8,93 (1952). Crwio, E., Modern Plastics, 29, 101 (July 1952). Day, H. hl., and Patterson, D. G., Ibid., 29, 116 (July 1952). De Vore, H. W., and Murray, H. C., Ibid., 28, 88 (April 1951:. Du Mond, T. C., Materials dl. Methods, 33, 60 (February 1951:. Ibid., 35,102 (February 1952). Ebers, E. S.,SOC.Plastics Engrs. J.,7, 31 (February 1951). Elliot, P. M., Modern Plastics, 29, 113 (July 1952). Farmer, N. W.,Plastics (London), 15, 89 (1950). Francis, R. J., Product Eng., 22, 85 (February 1951). Frey, S. E., Gibson, J. D., and Lafferty, R. H., Jr., IXD.1,:s~. CHEM.,42,2314 (1950). Fried, N., Winans, R. R., and Sieffert, L. E., Am. Xoc. 2'ect;/dg Materials Proc., 50,1383 (1950). Glick, S. E., SOC.Plastics Engrs. J., 7, 28 (February 1961). Goldberg, B., Cowosion, 7,47 (1951). Goss, W., Product Eng., 22, 137 (January 1951). Gross, M. R., Am. Soc. Testing Materials Proc., 51, 701 (1931). Halls, E. E., Plastics (London), 15, 194 (1950). Hanau, W. J., P a i n t and V a r n i s h Production, 41, No. 2, 1; KO.5 , 2 5 (1951). Hanson, D. B., Modern Plastics, 28, 88 (December 1950). Hargreaves, W. J., and Henson, F., Chem. Eng., 57, No. 2, 21,5 (1950). Harvey, C. C., Corrosion, 6,323 (1950). Himsworth, F. R., Chemistru & Industrg, 1950, 555. Hoogsteen, H. M., Young, A. E., and Smith, M. K., INU. CHEM.,42,1587 (1950). Huisman, G. R., and Wright,, R. H., ASTMBuZl., No. 164, 19 (1950). Hutchison, I. W., Tool Eng., 26, 38 (March 1951). James, D. D., Soc. Plastics Engrs. J., '7, 22 (February 1961). Javitz, A. E., Elec. N f g . 46, 76 (August 1950); 80 (September 1950). Jebens, W. J., and Ler. H , > Modern Plastics, 28, 104 (Jiine 1951).

October 1952 (53) (54) (55) (56) (57) (58) (59)

INDUSTRIAL AND ENGINEERING CHEMISTRY

Jupa, J. A., Ibid., 28,84 (December 1950). Kammermeyer, K., Proc. Iowa A m d . Sci., 57, 171 (1950). Xaatrop, J. E., World Oil,130, No. 5, 163 (1950). Klaas, P., Modern Plastics, 28, 79 (September 1950). Kline, G. M., IND. ENG.CREM.,42, 2001 (1950). Kline, G. M., Modern Plastics, 28, 113 (August 1951). Kline, G. M., Natl. Advisory Comm. Aeronaut., Research Memo. 51B23 (April, 23, 1951). (60) Krekeler, K., Plastics ( L o n d o n ) , 16, 226 (1951). (61) Kuenzi, E. W., A S T M BUZZ.,No. 164, 21 (1950). (62) Leavenworth, M., Corrosion, 8, No. 2, Suppl., 1 (1952). (63) Loewer, A. C., Eney, W. J., Seymour, R. B., and Pascoe, W., Am. SOC.Testing Materials Proc., 51, 1234 (1951). (64) McClenahan, W. T., Sewage and I n d . Wastes, 24, 1 (1952). (65) McFarland, R., Corrosion, 7, No. 4, SUPPI.,1 (1951). (66) McHard, J . A., and McIntyre. J. T., Chem. Eng., 58, No. 3, 214 (1951). (67) Ibid., 58, No. 4,212 (1951). (68) Ibid., 58, No. 5,251 (1951). (69) Ibid., 58, No. 9,290 (1951). (70) McHard, J. A,, and Van Vollrinburg, L., Ibid., 58, No 2 , 247 (1951). (71) Ibid., 58, No. 6,224 (1951). (72) Ibid., 58, No. 8,226 (1951). (73) Ibid., 58, No. 10,270 (1951). (74) Ibid., 58, No. 11,305 (1951). (75) McHenry, R. E., Frey, S. E., Gibson, J. D., and Laffelty, R. H., Jr., IND. ENG.CHEM.,42, 3217 (1950). (76) Materials & Methods, 33, 67 (January 1951). (77) Mill and Factory, 49,123 (July 1951). (78) Miller, W. J., Modern Plastics, 28, 74 (January 1951). (79) Modern Industry, 20, 53 (November 1950). (80) Modern Plastics, 28,83 (October 1950). 181) Ibid., 28,75 (November 1950). (82) Ibid., 28,59 (December 1950). (83) Ibid., 28, 55 (February 1951). (84) Ibid., p. 150. (85) Ibid., 28, 79 (April 1951). (86) Ibid., 28, 55 (May 1951). (87) Ibid., p. 144. (88) Ibid., p. 150. (89) Ibid., p. 162. (90) Ibid., 28, 123 (June 1951). (91) Ibid., p. 182. (92) Ibid., 28, 84 (July 1951). (93) Ibid., 28, 73 (August 1951); 29, 87 (September 1951). (94) Ibid., 29, 80 (September 1951). 195) Ibid.. D. 182 (96j Ibid.; 29, ls7 (October 1951). (97) Ibid., p. 192. (98) Ibid., p. 194. (99) Ibid., 29,87 (December 1951) (100) Ibid., p. 96. (101) Ibid., p. 172. (102) Ibid., 29, 102 (January 1952). (103) Ibid., 29, 71 (February 1952). (104) Ibid., 29, 57 (April 1952). (105) Ibid., p. 94. 1106) Ibid., 29, 75 (May 1952). 1107) Ibid.. D. 83. (108) 1bid.j 29, 76 (June 1952). (109) Ibid., p. 79. (110) Ibid., p. 85. (111) Ibid., p. 95. (112) Ibid., 29, 71 (July 1952). (113) Munger, C. C., Mech. Eng., 73, 899 (1951). (114) Murtfeldt, L. W., Paper Trade J.,131, No. 12, 23 (1950). (115) Narracott, E. S., Brit. Plastics, 24, 341 (1951). (116) Neumann, J. A., Industry and Welding, 23, No. 7, 36 (1950). 1117) Neumann, J. A., Modern Plastics, 27, 85 (June 1950). (115) Neumann, J. A., Ibid., 28, 97 (November 1950). (119) Xielson, A. R., and Parliman, J. H., Modern Packuging, 24, 141 (September 1950). (120) Oxley, G. W., Paint and V a r n i s h Production, 41, No. 3, 10 (1 951). (121) Palmer, N., Am. Machinist, 95, 172 (April 16, 1951). (122) Parks, C. E., Elec. Mfg., 48, 113 (August 1951). (123) Parks, C. E., SOC.Plastics Engrs. J., 7,36 (February 1951). (124) Parsons, G. B., Modern Plastics, 29, 129 (October 1951). (125) Plastics (London), 16,115 (1951). (126) Ibid., 17, 15 (1952). (127) Platzer, N., Modern Plastics, 28, 112 (July 1951). (128) Powell, G. M., Quarles, R. W., Spessard, C. I., McKnight, W. H., and Mullen, T. E., IbicE., 28, 129 (June 1951). (129) Preiswerk, E., and Charlton, J., Ibid., 28,85 (November 1950). (130) Quackenbos, H. M., Jr., Ibid., 28, 107 (July 1951).

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(131) Quarles, R. W., Severs, E. T., Frechtling, A. C., and Carpenter, H. S., Ibid., 29,99 (January 1952). (132) Recknagel, R. W., Product Eng., 23, 119 (February 1952). (133) Reid, D. G., A S T M Bull., No. 164, 28 (1950). (134) Reineck, E. A., Modern Plastics, 29, 122 (June 1952). (135) Reinhart, F. W., and Williams, H. C., A S T M Bull., No. 167, 60 (1950). (136) Reysen, W. H., Napolitan, D. S., Daniel, W. T., and Lafferty, R. H., Jr., Modern Plastics, 28, 102 (February 1951). (137) Rochow, E. G., and Rochow, T. G., J . Phys. and Colloid Chem., 55,9 (1951). (135) Roland, D. E., Materials & Methods, 32, 64 (December 1950). (139) Rubin, L. C., Product Eng., 21, 130 (May 1950). (140) Sandel, W. J., Sewage and I n d . Wastes, 23, 1448 (1951). (141) Schulze, A. P., Products Finishing 15, 44 (November 1950). (142) Servais, P. C., Mech. Eng., 73, 639 (1951). (143) Servais, P. C., and Youngs, D. C., Modern PZastics, 28, 83 (December 19501. (144) Seymour, R. B., Chem. Eng., 57, No. 9, 218 (1950). (145) Ibid., 57, No. 10,217 (1950). (146) Ibid., 57, No. 12, 226 (1950). (147) Ibid., 58, No. 1, 218 (1951). (148) Ibid., 58, No. 2, 247 (1951). (149) Ibid., 58, No. 3, 211 (1951). (150) Ibid., 58, No. 4, 213 (1951). (151) Ibid., 58, No. 5, 244 (1951). (152) Ibid., 58, No. 7, 222 (1951). (153) Ibid., 58, No. 8 , 226 (1951). (154) Ibid., 58, No. 9, 286 (1951). 11.55) Ibid.. 58. No. 10. 271 (19511. (i5i)Ibid., 58; No. 11; 297 (1951). (157) Seymour, R. B., Corrosion, 7, 151 (1951). (158) Seymour, R. B., Food Eng. (1952) (in press). (159) Sevmour. R. B.. “Metal Finishing Guide Book,” p. 78, New York, Finishing Publications, 1951. (160) Seymour, R. B., Southern Power and Ind., 69, No. 5,86; No. 6, 48 (1951). (161) Ibid., 70, No. 5,76 (1952). (162) Seymour, R. B., and Erich, E. A., Metal Finishiag, 50, No. 6, 117 (1952). (163) Seymour, R. B., and Erich, E. A,, “Metal Finishing Handbook,” 21st ed., New York, Finishing Publications, Inc., in press. (164) Seymour, R. B., and Erich, E. A., Petroleum PTocessing, 6, 561 (1951). (165) Seymour, R. B., and Fry, J. F., Chem. Eng., 59, 136 (1952). (166) Seymour, R. B., Pascoe, W., Eney, W. J., Loewer, A. C., Steiner, R. H., and Stout, R. D., J. Am. Water W o r k s Assoc., 43,1001 (1951). (167) Seymour, R. B., Pascoe, W., and Steiner, R. H., Water and Sewage W o r k s , 99, No. 5,210 (1952). (168) Seymour, R. B., and Steiner, R. H., Chem. Eng., 58, No. 12,265 (1951). (169) Ibid., 59, No. 1,264 (1952). (170) Ibid., 59, No. 2,288 (1952). (171) Seymour, R. B., and Steiner, R. H., Corrosion, 8 , 65 (1952). (172) Shearon, W. H., Chem. Eng. News, 30, 316 (1952). (173) Shephard, S., Corrosion, 7,279 (1951). (174) Silver, I., and Atkinson, H. B., Modern Plastics, 28, 113 (November 1950). (175) Simmons, C. R., Materials & Methods, 33, 81 (June 1951). (176) Simons, J. H., Chem. Eng., 57, 129 (July 1950). (177) Slone, M. C., Lamb, J. J., and Reinhart, F. W., Modern Plastics, 29,109 (June 1952). (178) Starr, J., Compressed Air Mag., 56, 209 (August 1951). (179) Swiggett, R. L., Modern Plastics, 28, 99 (August 1951). (180) Tator, K., Chem. Eng., 57, No. 10, 221 (1950). (151) Ibid., 58, No. 2,147 (1951). (182) Ibid., 58, No. 3, 211 (1951). (183) Ibid., 58, No. 4, 212 (1951). (184) Ibid., 58, No. 5, 250 (1951). (185) Ibid., 58, No. 6, 222 (1951). (186) Ibid., 58, No. 8 , 224 (1951). (187) Ibid., 58, No. 9, 257 (1951). (188) Ibid., 58, No. 11, 293 (1951). (189) Tompkins, P. C., Bizzell, 0. M., and Watson, D. C., IND. ENG. CHEM.,42,1475 (1950). (190) Touey, F. P., Modern Plastics, 29, 109 (November 1951). (191) Tyner, J. J., Finish, 7, No. 2,30 (1950). (192) White, R. B., Modern Plastics, 28, 103 (April 1951). (193) Willert, W. H., Ibid., 27,87 (July 1950). (194) Wilson, C. W., Ibid., 29, 106 (November 1951). (195) Wittkoff, H., Modern Packaging, 24, 111 (March 1951). (196) Yaeger, L. L., Product Eng., 22, 284 (May 1951). RECEIVED for review August 4 , 1952.

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