Materials, Their Properties and Uses 700 PHENOL-FORMALDEHYDE RESIN Juvelite was made in Germany by condensing the phenol and formaldehyde with the aid of mineral acids, and Laccain was made under an English patent by using organic acids as catalysts A Russian phenol resin, under the name of Karbolite, employed an equal amount of naphthalenesulfonic acid, C 10 H SO H, with the formaldehyde The hundreds of different phenolic molding compounds can be divided into six groups on the basis of major performance characteristics General-purpose phenolics are low-cost compounds with fillers such as wood flour and flock, and they are formulated for noncritical functional requirements They provide a balance of moderately good mechanical and electrical properties and are generally suitable in temperatures up to 300°F (149°C) Impact-resistant grades are higher in cost They are designed for use in electrical and structural components subject to impact loads The fillers are usually paper, chopped fabric, or glass fibers Electrical grades, with mineral fillers, have high electrical resistivity plus good arc resistance, and they retain their resistivity under high-temperature and high-humidity conditions Heat-resistant grades are usually mineral- or glass-filled compounds that retain their mechanical properties in the 375 to 500°F (190 to 260°C) temperature range Some of these, such as phenylsilanes, provide long-term stability at temperatures up to 550°F (288°C) Special-purpose grades are formulated for service applications requiring exceptional resistance to chemicals or water, or combinations of conditions such as impact loading and a chemical environment The chemical-resistant grades, for example, are inert to most common solvents and weak acids, and their alkali resistance is good Nonbleeding grades are compounded specially for use in container closures and for cosmetic cases The resins are marketed usually in granular form, partly polymerized for molding under heat and pressure, which complete the polymerization, making the product infusible and relatively insoluble They may also come as solutions, or compounded with reinforcing fillers and pigments The tensile strength of a molded part made form a simple phenol-formaldehyde resin may be only about 6,000 lb/in2 (41 MPa), with a specific gravity of 1.27 and dielectric strength of about 450 V/mil (17.7 ϫ 106 V/m) Reinforcement is needed for higher strength, and with a wood-flour filler the tensile strength may be as high as 10,000 lb/in2 (69 MPa) With a fabric filler the tensile strength may be 15,000 lb/in2 (103 MPa), or 18,000 lb/in2 (124 MPa) with a mineral filler The specific gravity is also raised, and the mineral fillers usually increase the dielectric strength Proper balance of fillers is important, since too large a quantity may produce brittleness Organic fillers absorb the resin and tend to Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PHONOLITE 701 brittleness and reduced flexural strength, although organic fibers and fabrics generally give high impact strength Wood flour is the usual filler for general-service products, but prepared compounds may have mineral powders, mica, asbestos, organic fibers, or macerated fabrics, or mixtures of organic and mineral materials Bakelite was the original name for phenol plastics, but trade names now usually cover a range of different plastics, and the types and grades are designated by numbers The specific gravity of filled phenol plastics may be as high as 1.70 The natural color is amber, and because the resin tends to discolor, it is usually pigmented with dark colors Normal phenol resin cures to single-carbon methylene groups between the phenolic groups, and the molded part tends to be brittle Thus, many of the innumerable variations of phenol are now used to produce the resins, and modern phenol resins may also be blended or cross-linked with other resins to give higher mechanical and electrical characteristics Furfural is frequently blended with formaldehyde to give better flow, lower specific gravity, and reduced cost The alkylated phenols give higher physical properties Phenol-phosphor resin is a phenol resin modified with phosphonitrilic chloride When cured, the resin contains 15% phosphorus, nitrogen, and less than chlorine The tensile strength is 7,000 lb/in2 (48 MPa), and it withstands continuous temperatures to 500°F (260°C) Phenol resins may also be cast and then hardened by heating The cast resins usually have a higher percentage of formaldehyde and not have fillers They are poured in a syrupy state in lead molds and are hardened in a slow oven Instead of making phenolic resins by polymerizing phenol formaldehyde using an acid catalyst, Enzymol International Inc uses a peroxidase enzyme obtained from soybeans to polymerize phenols in an aqueous solution of organic solvents at 122 to 140°F (50 to 60°C) Hydrogen peroxide is added to activate the enzyme Also known as clinkstone An aluminum-potassiumsilicate mineral used in the production of glass, and in Germany for the production of aluminum Phonolite is a variety of feldspar It varies greatly in composition, the best of the Eifel Mountains mineral containing 20 to 23.25% alumina, to K2O, to Na2O, and 50 to 52 silica A variety of this mineral, nepheline, from the Kòla Peninsula, is used in Russia to produce aluminum, with soda and potash as by-products Nepheline syanite from Peterborough Co., Ontario, Canada, is used in the ceramic industry in pottery, porcelain, and tile to increase translucency and reduce warpage and crazing From to 5% added to structural clay increases the mechanical strength As a substitute for potash feldspar in wall tiles, it increases PHONOLITE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 702 PHOSGENE the fluxing action and lowers the fusing point Agalmatolite, a name derived from the Greek words meaning image stone, is the massive form of phonolite from which the Chinese carve figures and basreliefs It has a soft, greasy feel and varies in color The common name for carbonyl chloride, COCl2, a colorless, poisonous gas made by the action of chlorine on carbon monoxide It was used as a poison war gas, called D-stoff by the Germans and collongite by the French But it is now used in the manufacture of metal chlorides and anhydrides, pharmaceuticals, perfumes, isocyanate resins, and for blending in synthetic rubbers It liquefies at 45.7°F (7.6°C) and solidifies at Ϫ180°F (Ϫ118°C) It is decomposed by water When chloroform is exposed to light and air, it decomposes into phosgene One part in 10,000 parts of air is a toxic poison, causing pulmonary edema For chemical warfare it is compressed into a liquid in shells Lacrimite, also a poison war gas, is thiophosgene mixed with stannic chloride Diphosgene, ClCOOC и Cl3, called green cross, superpalite, and perstoff, is an oily liquid boiling at 262°F (128°C) It is an intense lachrymator, has an asphyxiating odor, and is a lung irritant Because of its toxicity, most phosgene is produced and employed immediately in captive applications by Dow Chemical Co., Du Pont Co., and BASF AG The biggest use of the material is for toluene diisocyanate (TDI), which is then reacted into polyurethane resins for foams, elastomers, and coatings Approximately 1.4 tons (1.3 metric tons) of phosgene is needed to make 1.1 tons (1 metric ton) of TDI About 0.99 ton (0.9 metric ton) of phosgene is consumed to make 1.1 tons (1 metric ton) of polymethylene polyphenylisocyanate, also used for making polyurethane resins for rigid foams Polycarbonate manufacturers require 0.46 ton (0.42 metric ton) of phosgene per ton (0.91 metric ton) of product resin Polycarbonate is used for making break-resistant housings, signs, glazings, and electrical tools Phosgene also is a reactant for methyl isocyanate, diphenylmethane-4,4-isocyanate, acyl chloride, chloroformate esters, diethyl carbonate, and dimethyl carbamoyl chloride The isocyanates are used in pesticides, and the di- and polyisocyanates are used in adhesives, coatings, and elastomers PHOSGENE Copper-base alloys with low phosphorus content, originally called steel bronze when first produced at the Royal Arsenal in Vienna It was 92–8 bronze deoxidized with phosphorus and cast in an iron mold It is now any bronze deoxidized by the addition of phosphorus to the molten metal It may or may not contain residual phosphorus in the final state Ordinary bronze frequently PHOSPHOR BRONZE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PHOSPHOR BRONZE 703 contains cuprous oxide formed by the oxidation of the copper during fusion By the addition of phosphorus, a powerful reducing agent, a complete reduction of the oxide takes place Phosphor bronzes have excellent mechanical and cold-working properties and low coefficients of friction, making them suitable for springs, diaphragms, bearing plates, and fasteners In some environments, such as salt water, they are superior to copper Phosphor bronzes have been known by many trade names, including Duraflex, a hard-rolled strip and wire product for springs; Carbobronze, hard-drawn tubing and rod for bearings; Corvic, a spring grade with a tensile strength of 95,000 lb/in2 (655 MPa) and an electrical conductivity of 42% that of copper; and Telnic, a 1% nickel, 0.5 tellurium, 0.2 phosphorus grade So-called white phosphor bronze is not a bronze, but a 72% lead, 15 phosphor tin, 12 antimony, copper alloy Standard wrought phosphor bronzes are designated C50100 to C54800 Tin, which ranges from as much as 0.8 to 11% depending on the alloy, is the principal alloying element, although leaded alloys may contain as much lead (4 to 6%, for example) as tin Phosphorus content is typically on the order of 0.1 to 0.35%; zinc, to 0.3 (1.5 to 4.5% in C54400); iron, to 0.1; and lead, to 0.05 (0.8 to in leaded alloys) The principal alloys were formerly known by letter designations representing nominal tin content: phosphor bronze A, 5% tin (C51000); phosphor bronze B, 4.75 tin (C53200); phosphor bronze C, tin (C52100); phosphor bronze D, 10 tin (C52400); and phosphor bronze E, 1.25 tin (C50500) Phosphor bronze E, being almost 99% copper, is one of the leanest of these bronzes in the way of alloying ingredients and is used for electrical contacts, pole-line hardware, and flexible tubing Its electrical conductivity is about half that of copper, and it is readily formed, soldered, brazed, and flash-welded Thin, flat products have tensile yield strengths ranging from about 12,000 lb/in2 (83 MPa) in the annealed condition to 75,000 lb/in2 (517 MPa) in the extra-spring temper More highly alloyed C54400 (4% tin, lead, and zinc, nominally) is about one-fifth as electrically conductive as copper, has good forming characteristics, and has 80% the machinability of C36000, a free-machining brass Its ultimate tensile strength ranges from about 48,000 lb/in2 (331 MPa) in the annealed condition to 100,000 lb/in2 (690 MPa) in the extra-spring temper Uses include bearings, bushings, gear shafts, valve components, and screw-machine products An alloy C94400, which has been called a phosphor bronze, is suitable for sand castings and centrifugal castings The nominally 81% copper, 11 lead, tin alloy is 10% as electrically conductive as copper and, as sand-cast, has a typical ultimate tensile strength of 32,000 lb/in2 (221 MPa) and a tensile yield strength of 16,000 lb/in2 (110 MPa) It matches the machinability of C54400 and is used mainly for bushings and bearings Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 704 PHOSPHOR COPPER An alloy of phosphorus and copper, used instead of pure phosphorus for deoxidizing brass and bronze, and for adding phosphorus in making phosphor bronze It comes in 5, 10, and 15% grades and is added directly to the molten metal It serves as a powerful deoxidizer, and the phosphorus also hardens the bronze Even slight additions of phosphorus to copper or bronze increase fatigue strength Phosphor copper is made by forcing cakes of phosphorus into molten copper and holding until the reaction ceases Phosphorus is soluble in copper up to 8.27%, forming Cu3P, which has a melting point of about 1305°F (707°C) A 10% phosphor copper melts at 1562°F (850°C) and a 15% at about 1872°F (1022°C) Alloys richer than 15% are unstable Phosphor copper is marketed in notched slabs or in shot In Germany phosphor zinc was used as a substitute to conserve copper Metallophos is a name for German phosphor zinc containing 20 to 30% phosphorus The name phosphor copper is also applied to commercial copper deoxidized with phosphorus and retaining up to 0.50% phosphorus The electrical conductivity is reduced about 30%, but the copper is hardened and strengthened Phosphor tin is a master alloy of tin and phosphorus used for adding to molten bronze in the making of phosphor bronze It usually contains up to 5% phosphorus and should not contain lead It looks like antimony, with large glittering crystals, and is marketed in slabs PHOSPHOR COPPER PHOSPHORIC ACID Also known as orthophosphoric acid A color- less, syrupy liquid of composition H3PO4 used for pickling and rustproofing metals; for the manufacture of phosphates, pyrotechnics, and fertilizers; as a latex coagulant; as a textile mordant; as an acidulating agent in jellies and beverages; and as a clarifying agent in sugar syrup The specific gravity is 1.65 and melting point 164°F (73.6°C), and it is soluble in water The usual grades are 90, 85, 75%, technical 50%, and dilute 10% As a cleanser for metals, phosphoric acid produces a light etch on steel, aluminum, or zinc, which aids paint adhesion Deoxidine is a phosphoric acid cleanser for metals Nielite D is phosphoric acid with a rust inhibitor, used as a nonfuming pickling acid for steel Albrite, from Albright & Wilson Americas, is available in 75, 80, and 85% concentrations in food and electronic grades, both high-purity specifications DAB and Phosbrite, also from the same company, are called Bright Dip grades, for cleaning applications Phosphoric anhydride, or phosphorus pentoxide, P O , is a white, water-soluble powder used as a dehydrating agent and as an opalizer for glass It is also used as a catalyst in asphalt coatings to prevent softening at elevated temperatures and brittleness at low temperatures Granusic is this material in granular form for removing water from gas streams Production of phosphoric acid is by digestion of apatite ore, a tricalcium phosphate, with sulfuric acid, and Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PHOSPHORUS 705 purification For industrial grades, white phosphorus or yellow phosphorus is burned in excess air, and the resulting phosphorus pentoxide is hydrated A nonmetallic element, symbol P, widely diffused in nature and found in many rock materials, in ores, in the soil, and in parts of animal organisms Commercial phosphorus is obtained from phosphate rock by reduction in the electric furnace with carbon, or from bones by burning and treating with sulfuric acid Phosphate rock occurs in the form of land pebbles and as hard rock It is plentiful in the Bone Valley area of Florida, and it also comes from Tennessee, Idaho, and South Carolina Vast quantities are mined in Morocco and Tunisia Large deposits are found on many of the Pacific Islands, the Christmas Island resources being estimated at 30 ϫ 106 tons (27 ϫ 106 metric tons) and those on Nauru at 100 ϫ 106 tons (91 ϫ 106 metric tons) It is a calcium phosphate high in P2O5 The mineral apatite, widely distributed in the Appalachian range, in Idaho, Brazil, and French Oceania, is also a source of phosphorous, containing up to 20% P2O5, with iron oxide and lime The Egyptian rock contains 62 to 70% tricalcium phosphate The aluminocalceous phosphate rock of Senegal is treated to obtain a very soluble fertilizer known as phosphal Florida hard phosphate rock contains 80% phosphate of lime A ton (0.9 metric ton) of phosphorus is obtained from 7.25 tons (6.58 metric tons) of rock, requiring 30 lb (14 kg) of electrodes and 11,850 kW of electricity The Tennessee Valley Authority produces about tons (7 metric tons) of expanded slag for each ton (0.9 metric ton) of phosphorus produced from the phosphate rock The slag from the smelter is run onto a forehearth at about 2000°F (1093°C) and treated with water, high-pressure steam, and air The expanded slag formed is crushed to 0.375-in (0.95-cm) size, bulking 50 lb/ft3 (801 kg/m3) It is called TVA slag and is used for making lightweight concrete blocks The superphosphate used for fertilizers is made by treating phosphate minerals with concentrated sulfuric acid It is not a simple compound, but may be a mixture of calcium acid phosphate, CaHPO4, and calcium sulfate Nitrophosphate for fertilizer is made by acidulating phosphate rock with a mixture of nitric and phosphoric acids, or with nitric acid and then ammoniation and addition of potassium or ammonium sulfate Such products are made by Cargill, Inc., and International Minerals & Chemicals Corp Natural rock phosphate in finely ground form is also used as a fertilizer for legume crops, but the untreated natural rock is not readily soluble and is thus not as quick-acting as a fertilizer There are two common forms of phosphorus, yellow and red The former, also called white phosphorus, P4, is a light-yellow, waxlike solid, phosphorescent in the dark and exceedingly poisonous Its specific PHOSPHORUS Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 706 PHOSPHORUS gravity is 1.83, and it melts at 111°F (44°C) It is used for smoke screens in warfare and for rat poisons and matches Yellow phosphorus is produced directly from phosphate rock in the electric furnace It is cast in cakes of to lb (0.45 to 1.36 kg) each Red phosphorus is a reddish-brown, amorphous powder, having a specific gravity of 2.20 and a melting point of 1337°F (725°C) Red phosphorus is made by holding white phosphorus at its boiling point for several hours in a reaction vessel Both forms ignite easily Amorphous phosphorus, or crystalline black phosphorus, is made by heating white phosphorus for extended periods It resembles graphite and is less reactive than the red or white forms, which can ignite spontaneously in air Black phosphorus is made by this process by Atomergic Chemetals Corp Phosphorus sulfide, P4S3, may be used instead of white phosphorus in making matches Phosphorus pentasulfide, P2S5, is a canary-yellow powder of specific gravity 1.30, or solid of specific gravity 2.0, containing 27.8% phosphorus, used in making oil additives and insecticides It is decomposed by water Phosphorus is an essential element in the human body, a normal person having more than a pound of it in the system, but it can be taken into the system only in certain compounds Nerve gases used in chemical warfare contain phosphorus which combines with and inactivates the choline sterase enzyme of the brain This enzyme controls the supply of the hormone which transmits nerve impulses, and when it is inactivated, the excess hormone causes paralysis of the nerves and cuts off breathing Organic phosphates are widely used in the food, textile, and chemical industries Tributyl phosphate, for example, is a colorless liquid, used as a plasticizer in plastics and as an antifoaming agent in paper coatings and textile sizings Briquest is an organic phosphate from Albright & Wilson Inc that is employed for scale and corrosion control, ore flotation, pigment dispersion, and detergents Diethylchlorothiophosphate (DECTP) is a highly reactive intermediate chemical from Ethyl Corp Flour and other foodstuffs are fortified with ferric phosphate, FePO4 и 2H2O Iron phosphate is used as an extender in paints Tricalcium phosphate, Ca3(PO4)2, is used as an anticaking agent in salt, sugar, and other food products and to provide a source of phosphorus The tricalcium phosphate used in toothpastes as a polishing agent and to reduce the staining of chlorophyll has formula (10CaO и H O и 3P2O5)3H2O and is a fine, white powder Dicalcium phosphate, used in animal feeds, is precipitated from the bones used for making gelatin, but is also made by treating lime with phosphoric acid made from phosphate rock Diammonium phosphate, (NH4)2HPO4, is a mildly alkaline, white, crystalline powder used in ammoniated dentifrices, for pH control in bakery products, in making phosphors and to prevent afterglow in matches, and for flameproofing paper Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PHTHALIC ANHYDRIDE 707 For manufacturing operations, phosphorus is generally utilized in the form of intermediate chemicals, but the phosphorus used for doping semiconductors and in electroluminescent coatings is 99.9999% pure Phosphorus trichloride, PCl3, is an important chemical for making phosphites It is a colorless liquid boiling at 169°F (76°C) It decomposes in water to form phosphorus and hydrochloric acid Phosphorus oxychloride, POCl3, is a very reactive liquid used as a chlorinating agent and for making organic chemicals In water it decomposes to form phosphoric and hydrochloric acids Phosphorus thiochloride, PSCl3, is a yellowish liquid containing 18.5% phosphorus and 18.6 sulfur It is used for making insecticides and oil additives Phosphine, PH , is produced by hydrolysis of a metal phosphide, such as calcium phosphide or aluminum phosphide A toxic gas, it is widely used as a ligand in catalysis A white, crystalline material of composition C6H4(CO)2O, with a melting point of 267°F (130.8°C), soluble in water and in alcohol It is made by oxidizing naphthalene, or it is produced from orthoxylene derived from petroleum BASF Corp markets the product both as flake and in the molten state It is used in the manufacture of alkyd resins and for the production of dibutyl phthalate and other plasticizers, dyes, and many chemicals Chlorinated phthalic anhydride is also used as a compounding medium in plastics It is a white, odorless, nonhygroscopic, stable powder containing 50% chlorine It gives higher temperature resistance and increased stability to plastics Niagathal is a chlorinated phthalic anhydride of Niagara Alkali Co Tetrahydrophthalic anhydride is a white, crystalline powder with a molecular weight of 152.1, melting at 212°F (100°C), used to replace phthalic anhydride where a lighter color is desired It is produced by condensing butadiene with maleic anhydride In synthetic resin coatings it gives higher adhesion Terephthalic acid may be obtained as a by-product in the production of phthalic anhydride from petroleum It has a long-chain alkyl group having an amide linkage on one end and a methyl ester on the other It is used for producing polyethylene terephthalate and other polyesters The esters can also be made from dimethyl terephthalate, a molten material that burns readily when ignited The dust can form explosive mixtures with air The terephthalates are useful as textile and tire-cord fibers, plastic tape, and food-packaging polymers Their sodium salt is used as a gelling agent for high-temperature lubricating greases for uses to 600°F (316°C) It forms fine crystallites of soft, flexible fibers in the grease Oronite GA10 is this material Isophthalic acid, made by oxidation of ethyl benzene and orthoxylene, produces alkyd paint resins of greater heat stability than phthalic anhydride Maleic anhydride, (CHCO)2O, is a white, crystalline solid used to replace phthalic PHTHALIC ANHYDRIDE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 708 PIASSAVA anhydride in alkyd resins to increase the hardness for baking enamels and to resist yellowing Its use in papermaking, as sizing, is growing, as are markets in lubricating-oil additives, acidulation, where it is a flavoring agent, and agricultural chemicals Maleic anhydride is also a building block for L-aspartame, used for making NutraSweet, the aspartame synthetic sweetener Maleic anhydride was traditionally made from benzene, but n-butane has become the feedstock of choice because of its lower cost and because benzene is a carcinogen In the United States, the transition was completed in the late 1980s Recent uses for maleic anhydride, and maleic acid recovered from the catalytic oxidation of butane to maleic anhydride, are the production of chemical intermediates 1,4-butanediol (BDO), tetrahydrofuran (THF), and gammabutyrolactone (GBL) Also called Pará grass and monkey grass A coarse, stiff, and elastic fiber obtained from a species of palm tree, Leopoldinia piassaba, of Brazil, used for making brushes and brooms The plant has long beards of bristlelike fibers, which are combed out and cut off the young plants These fibers sometimes reach a length of ft (1.2 m) The soft, finer fibers are made into cordage, and the coarser ones are used for brushes Piassava is very resistant to water The fiber for brush manufacture is separated into three classes, the heavy fibers being known as bass, the medium as bassine, and the fine as palmyra The bass is used for heavy floor sweeps The fiber of the palm Attalea funifera, which grows in the state of Bahia, Brazil, and is also called piassava, is a harder and stronger material than the piassava of Amazonas It is used for marine cordage and is resistant to salt water A substitute for piassava is acury, from the leaves of the palm A phalerata of Matto Grosso It is used for cordage and brushes, and the coarser fibers are used for brooms PIASSAVA Acids used for pickling, or cleaning castings or metal articles The common pickling bath for iron and steel is composed of a solution of sulfuric acid and water, part acid to to 10 parts water being used This acid attacks the metal and cleans it of the oxides and sand by loosening them For pickling scale from stainless steels a 25% cold solution of hydrochloric or sulfuric acid is used, or hydrofluoric acid with the addition of anhydrous ferric sulfate is used Hydrofluoric acid solutions are sometimes used for pickling iron castings This acid attacks and dissolves away the sand itself For bright-cleaning brass, a mixture of sulfuric acid and nitric acid is used For a matte finish the mixed acid is used with a small amount of zinc sulfate Copper and copper alloys can be pickled with sulfuric PICKLING ACIDS Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PICKLING ACIDS 709 acid to which anhydrous ferric sulfate is added to speed the action, or sodium bichromate is added to the sulfuric acid to remove red cuprous oxide stains Brass forgings are pickled in nitric acid to bring out the color Since all of these acids form salts rapidly by the chemical action with the metal, they must be renewed with frequent additions of fresh acid The French pickling solution known as framanol, used for aluminum, is a mixture of chromium phosphate and triethanolamine The latter emulsifies the grease and oil, and the aluminum oxide film is dissolved by the phosphoric acid, leaving the metal with a thin film of chromic oxide The temperature of most pickling is from 140 to 180°F (60 to 82°C) An increase of 20°F (11°C) will double the rate of pickling Acid brittleness after pickling is due to the absorption of hydrogen when the acid acts on iron, and is reduced by shortening the pickling time Inhibitors are chemicals added to reduce the time of pickling by permitting higher temperatures and stronger solutions without hydrogen absorption Hibitite, of Monsanto, is a brown liquid of composition C27H45NO10S2, used as a metal pickling inhibitor Addition of a small amount of 2% tincture of iodine to a 5% sulfuric acid solution gives a 95% retardation of acid attack on steel without decreasing the rate of dissolution of rust In plating baths, fluoboric acid, HBF4, has high throwing power and has a cleansing effect by dissolving sand and silicides from iron castings and steel surfaces It is a colorless liquid with specific gravity of 1.33 and decomposes at 266°F (130°C) Pennsalt FA-42, of Atochem North America Inc., is this material It is a 42% solution of fluoboric acid for pickling and for control of acidity of plating baths Phosphoric acid is employed in hot solution as a dip bath for steel parts to be finished to a rough or etched surface It leaves a basic iron phosphate coating on the steel which is resistant to corrosion and gives a rough base for the finish Coslettized steel is steel rustproofed by dipping in a hot solution of iron phosphate and phosphoric acid Parkerized steel is rustproofed steel treated in a bath of iron and manganese phosphates Bonderized steel is steel treated with phosphoric acid and a catalyst to give a rough, tough, rust-resistant base for paints Granodized steel is produced with zinc phosphate In general, the coatings left on steel by phosphate treatments are extremely thin, not over 0.0002 in (0.0005 cm) The iron-manganese coatings are black, and the iron-zinc-phosphate coatings are gray Metals can be treated with alkaline solutions, too Rust can be removed by caustic soda baths in which is mixed a sequestrant, such as sodium gluconate or ethylenediaminetetracetic acid (EDTA), to complex the dissolved iron and keep it from precipitating Hampene EDTA is a chelating agent from Hampshire Div of W R Grace & Co In general, the alkali treatments work more slowly than acid-based ones Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses POTASSIUM CHLORATE 755 magnesium oxide, phosphorus pentoxide, and other oxides The sylvite ore mined at Carlsbad, New Mexico, contains KCl and NaCl It is electrically refined to 99.95% KCl, and is used to produce caustic potash Electrolysis of the chloride solution yields caustic potash An elementary metal, symbol K, atomic weight 39.1, also known as kalium It is silvery white, but oxidizes rapidly in air and must be kept submerged in ether or kerosene It has a low melting point, 145°F (63°C), and a boiling point of 1392°F (756°C) The specific gravity is 0.855 at 68°F (20°C) It is soluble in alcohol and in acids It decomposes water with great violence Potassium is obtained by the electrolysis of potassium chloride Potassium metal is used in combination with sodium as a heat-exchange fluid in atomic reactors and high-temperature processing equipment A potassium-sodium alloy contains 78% potassium and 22 sodium It has a melting point of 12°F (Ϫ11°C) and a boiling point of 1393°F (756°C) and is a silvery, mobile liquid Cesium-potassium-sodium alloys are called BZ Alloys Potassium hydride is used for the photosensitive deposit on the cathode of some photoelectric cells It is extremely sensitive and will emit electrons under a flash so weak and so rapid as to be imperceptible to the eye Potassium diphosphate, KH2PO4, a colorless, crystalline, or white powder soluble in water, is used as a lubricant for wool fibers to replace olive oil in spinning wool It has the advantages that it does not become rancid as oil does and can be removed without scouring Potassium, like sodium, has a broad range of use in its compounds, giving strong bonds Metallurgically it is listed as having a body-centered-cubic structure, but the atoms arrange themselves in pairs in the metal as K2, and the structure is cryptocrystalline POTASSIUM Also known as chlorate of potash and potassium oxymuriate A white, crystalline powder, or lustrous, crystalline substance, of composition KClO3, employed in explosives, chiefly as a source of oxygen It is also used as an oxidizing agent in the chemical industry, as a cardiac stimulant in medicine, and in toothpaste It melts at 675°F (357°C) and decomposes at 752°F (400°C) with the rapid evolution of oxygen It is odorless but has a slightly bitter, saline taste The specific gravity is 2.337 It is not hygroscopic, but is soluble in water It imparts a violet color to the flame in pyrotechnic compositions Potassium chloride is a colorless or white, crystalline compound of composition KCl, used for molten salt baths for the heat treatment of steels Trona is a fertilizer- and explosives-grade material from Kerr-McGee Chemical Corp Morton is a pharmaceutical-quality POTASSIUM CHLORATE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 756 POTASSIUM CYANIDE potassium chloride that has no iodine contamination It is sold by Morton Salt The specific gravity is 1.987 A bath composed of three parts potassium chloride and two parts barium chloride is used for hardening carbon-steel drills and other tools Steel tools heated in this bath and quenched in a 3% sulfuric acid solution have a very bright surface A common bath is made up of potassium chloride and common salt and can be used for temperatures up to 1652°F (900°C) POTASSIUM CYANIDE A white, amorphous or crystalline solid of com- position KCN, employed for carbonizing steel for case hardening and for electroplating The specific gravity is 1.52, and it melts at about 1550°F (843°C) It is soluble in water and is extremely poisonous, giving off the deadly hydrocyanic acid gas For cyaniding steel the latter is immersed in a bath of molten cyanide and then quenched in water, or the cyanide is rubbed on the red-hot steel For this use, however, sodium cyanide is usually preferred, because of its lower cost and the higher content of CN in the latter Commercial potassium cyanide is likely to contain a proportion of sodium cyanide Potassium ferrocyanide, or yellow prussiate of potash, can also be used for casehardening steel It has composition K4Fe(CN)6 and comes in yellow crystals or powder The nitrogen as well as the carbon enters the steel to form the hard case Potassium ferricyanide, or red prussiate of potash, is a bright-red, granular powder of composition K3Fe(CN)6, used in photographic reducing solutions, in etching solutions, in blueprint paper, and in silvering mirrors Redsol crystals, of American Cyanamid Co., is the name of this chemical for use as a reducer and mild oxidizing agent, or toner, for photography Potassium cyanate, KCNO, is a white, crystalline solid used for the production of organic chemicals and drugs It melts at 590°F (310°C) The potassium silver cyanide used for silver plating comes in white, water-soluble crystals of composition KAg(CN)2 SelRex, of Bart-Messing Corp., is this material Potassium gold cyanide has a similar function in gold plating Platina, of Platina Laboratories, comes as colorless tablets that are soluble in both water and alcohol Also called niter and saltpeter, although these usually refer to the native mineral A substance of composition KNO3, it is used in explosives, for bluing steel, and in fertilizers A mixture of potassium nitrate and sodium nitrate is used for steel-tempering baths The mixture melts at 482°F (250°C) Potassium nitrate is made by the action of potassium chloride on sodium nitrate, or Chile saltpeter It occurs in colorless, prismatic crystals, or as a crystalline, white powder It has a sharp saline taste POTASSIUM NITRATE Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses POTATO 757 and is soluble in water The specific gravity is 2.1, and the melting point is 639°F (337°C) It is found in nature in limited quantities in the alkali region of the western United States Potassium nitrate contains a large percentage of oxygen which is readily given up and is well adapted for pyrotechnic compounds It gives a beautiful, violet flame in burning It is used in flares and signal rockets Potassium nitrite is a solid of composition KNO2 used as a rust inhibitor, for the regeneration of heat-transfer salts, and for the manufacture of dyes The bulbous tubers of the roots of the annual plant Solanum tuberosum, native to Peru but now grown in many parts of the world It is used chiefly as a direct food, but is also employed for making starch and alcohol The potato was brought to Europe in 1580, and received the name of Irish potato when brought to New England in 1719 by Irish immigrants The plant is hardy and has a short growing cycle, making it adaptable to many climates The tuber contains about 78% water, 18 starch with some sugar, proteins, potash, and only about 0.1 fats The average water loss in storage is about 11% There are more than 500 varieties of potato cultivated Dehydrated potato, produced as powder, flake, and porous granules, is widely used in restaurants and institutions and is marketed under various trade names for home use The sweet potato is the root bulb of the trailing perennial vine Ipomoea batata, native to tropical America, but now grown extensively in the southern United States and in warm climates In South America it is known by the Carib name batata Like the white potato, the sweet potato has a high water content, but is rich in sugars There are many varieties and two general types: one with a dry, mealy, yellow flesh and the other with a soft, gelatinous flesh higher in sugars The latter type is called yam in the United States, but the true yam is a larger tuber from the climbing plant Diascorea alata, grown widely in the West Indies The sweet potato is used as a direct food, but large amounts are also employed for making preserves, starch, and flour for confectionery Alamalt is cooked and toasted sweet potato ground to a powder for use in confectionery It adds flavor as well as sugar to the confectionery Sweet-potato flake, used in foodstuffs, is cooked and dehydrated sweet potato in orange-colored flakes with the flavor of candied sweet potato It is reconstituted with milk or water The taro is the root tuber of the large, leafy plant Colocasia esculenta, which constitutes one of the chief foods of southeast Asia and Polynesia There are more than 300 varieties grown The tuber is high in starch, has more proteins than the potato, but has an acrid taste until cooked The pasty starch food known as poi in the Pacific Islands is made from taro In Micronesia the taro is called jaua, and the POTATO Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 758 PRECIOUS METALS mwang plant, Cyrtosperma chamissonis, is called taro This plant is larger, and the rootstock weighs as much as 50 lb (23 kg), while the taro does not exceed lb (2 kg) Taro matures in months, while the mwang requires years The dasheen is a variety of taro grown in the southern United States The yautia, grown in the West Indies, resembles the taro, but is from the large plant Xanthosma sagittifolium It is high in starch and has greater food value than the potato PRECIOUS METALS The metals gold, silver, and platinum, which are used for coinage, jewelry, and ornaments, and also for industrial applications Expense or rarity alone is not the determining factor; rather, a value is set by law, with the coinage having an intrinsic metal value as distinct from a copper coin, which is merely a token with little metal value The term noble metal is not synonymous, although a metal may be both precious and noble, such as platinum Although platinum was once used in Russia for coinage, only gold and silver fulfill the three requisites for coinage metals Platinum does not have the necessary wide distribution of source The noble metals are gold, platinum, iridium, rhodium, osmium, and ruthenium Unalloyed, they are highly resistant to acids and corrosion Radium and certain other metals are more expensive than platinum but are not classified as precious metals Because of the expense of the platinum noble metals, they may be alloyed with gold for use in chemical crucibles Platino is an alloy of 89% gold and 11 platinum Palau is the name of an alloy of gold and palladium, and rhotanium is a rhodium-gold alloy Sheet metals that are precoated or treated at the mill so as to eliminate or minimize final finishing by the user The metals are made in a ready-to-use form with a decorative and/or functional finish already applied A large number and variety of prefinished metals have been developed Prepainted metals are produced using various organic coatings on many common ferrous and nonferrous metals Extra durability or special decorative effects are provided by plastic-metal laminates Polyvinyl chloride, polyvinyl fluoride, and polyester are the plastics commonly used Black-coated steel is used to give a high thermal emittance in electronic equipment The base metal is aluminum-deoxidized steel containing 0.13% carbon, 0.45 manganese, 0.04 maximum phosphorus, and 0.05 maximum sulfur The steel is coated with a 5% by weight layer of nickel oxide, which is reduced in a hydrogen furnace to form a spongy layer of nickel This sponge is impregnated with a carbon slurry to form a black, carbonized surface PREFINISHED METALS Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PRESERVATIVES 759 Preplated metals consist of a thin, electrodeposited plate of one metal or alloy on a base, or substrate, usually sheet, of another metal Steel is the most common base metal, and it is commonly plated with brass, chromium, copper, nickel, nickel-zinc, or zinc Other common preplated metals are chromium-plated brass, copper, nickel, or zinc; and nickel-plated brass, copper, or zinc The surface of the plate may be mirror-bright, satin, bright satin, embossed, antique, or black, or may have some other finish The plate, usually 0.001 to 0.005 in (0.025 to 0.127 mm) thick, is sufficiently ductile to withstand shearing, bending, drawing, and stamping operations Common joining methods include lock-seaming, stud welding, adhesive bonding, and spot welding One of the earliest groups of preplated metals included Brassoid, Nickeloid, and Chromaloid of American Nickeloid, which were brass-, nickel-, and chromium-plated zinc sheet Other producers of preplated metals have included Apollo Metals, National Sheet Metal, and Thomas Steel Strip Prefinished metals are now available with almost any metal plated or bonded to almost any other metal, or single metals may be had prefinished in colors and patterns They come in bright or matte finishes and usually have a thin paper coating on the polished side, which is easily stripped off before or after forming The metals are sold under a variety of trade names and are used for decorative articles, appliances, advertising displays, panels, and mechanical parts PRESERVATIVES Chemicals used to prevent oxidation, fermentation, or other deterioration of foodstuffs The antioxidants, inhibitors, and stabilizers used to retard deterioration of industrial chemicals are not usually called preservatives The most usual function of a preservative is to kill bacteria, and this may be accomplished by an acid, an alcohol, an aldehyde, or a salt A legal requirement under the Food and Drug Act is that a preservative be nontoxic in the quantities permitted Sugar is the most commonly used preservative for fruit products Sodium chloride is used for protein foods Sodium nitrate is reduced to sodium nitrite in curing meats, and the nitrite has an inhibitory action on bacterial growth, the effect being greatest in acid flesh Potassium sorbate, KOCOCH:CH:CHCH3, a white, water-soluble powder, inhibits the growth of many molds, yeasts, and bacteria which cause food deterioration, and it is used in cheese, syrups, pickles, and other prepared foods The inhibitory effect of organic acids is due chiefly to the undissociated molecule Acetic acid is normally more toxic to bacteria than lactic acid; but when sugar is present, the reverse is true, and citric acid then has little toxicity The inhibitory action of inorganic acids is due mainly to the pH change which they produce The antimicrobe Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 760 PRIMER effect of the vanillic acid esters generally increases with increasing molecular weight Only small quantities of chemicals are usually needed for preservation Isobutyl vanillate, an ester of vanillic acid, is effective as a preserving agent in milk and some other foods when only 0.10 to 0.15% is used Preservatives are also marketed for external application to foodstuffs in storage, though these are more properly classified as fumigants Beverages containing fruit juices or little carbonation are preserved with less than 0.05% sodium benzoate Methyl, propyl, butyl, and ethyl parabens; potassium sorbate; sodium dihydroacetate; and imidazolidinyl urea are all industrial microbials used in the food, cosmetic, and pharmaceutical industries Abiol, grade CFTA, is a water-soluble, stable, wide-pHrange-acting preservative of the imidazolidinyl urea family Grade NF is imidurea Both, available from Tri-K Industries, Inc., are particularly effective in conjunction with the parabens A surfacing material employed in painting or finishing to provide an anchorage or adhesion of the finishing material A primer may be colorless, or it may have color In the latter case, it is sometimes called an undercoat A primer is distinct from the filler coat used on woods to fill the pores and thus economize on the more expensive finish Primers for industrial or production finishing are of two types: air-dry and baking The air-dry types have drying-oil vehicle bases and are usually called paints They may be modified with resins They are not used as extensively as the baking-type primers, which have resin or varnish vehicle bases These dry chiefly by polymerization Some primers, known as flash primers, are applied by spraying and dry by solvent evaporation within 10 In practically all primers, the pigments impart most of the anticorrosion properties to the primer and, along with the vehicle, determine its compatibility with and adherence to the base metal Primer coats of red lead paint were formerly much used on construction steel to give corrosion resistance, but chromate or phosphate primers are now more common Barium potassium chromate gives a pale-yellow coating with good anticorrosion properties for steel, aluminum, and magnesium Zinc yellow paints may also be used as primer coats on metal Zinc chromate is used as a primer on steel It has a tendency to dissolve when moisture penetrates the paint, and this dissolved chromate retards corrosion of the steel Zinc phosphate primers applied to iron and steel give corrosion resistance and improve paint adhesion Manganese phosphate forms a dense, crystalline coating on steel, which acts as a corrosionresistant base for paint A mixture of 95% zinc powder and 5% epoxy resin binder in a solvent gives a gray, metallic finish, and the zinc PRIMER Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PROTEIN 761 blocks corrosion by galvanic action In addition to the pigment, various corrosion inhibitors may be used in primer paints Ammonium ferrous phosphate, NH FePO и H O, has a platelike structure which gives impermeability to the film as well as adding corrosion resistance It is greenish A primer is especially required in the finishing of sheet-metal objects that are likely to receive dents or severe service, but it is not usually necessary for castings or roughened surfaces For sheet-metal work, baked enamels were formerly much used for the primers for lacquer finishes, but synthetic resin primers give good adhesion and are less expensive High-performance solvent- or waterborne epoxy primers with chromate corrosion inhibitors have traditionally protected U.S Navy aircraft aluminum components from the corrosive effects of seawater and high humidity With the chromates implicated as carcinogenic, nontoxic inhibitors have been sought Thus far, inorganic nonchromated solutions based on permanganate, cobalamine, and cericion as the active corrosion-inhibiting agent have proved only marginally comparable at best in corrosion resistance and paint adhesion The Navy-developed Chromium III pretreatment (SJS6-7) has demonstrated comparable corrosion resistance and paint adhesion in laboratory tests And sol-gel formulations of organic or inorganic polymers, based on the hydrolysis and condensation of metal alkoxides, show promise Other alternatives are special aliphatic polyurethane topcoats; SJS12, a lead- and chromium-free, high-solids polyurethane self-priming topcoat (SPT); and a waterborne polyurethane topcoat Waterborne epoxy-based BR6747 primer, from Cytec Engineered Materials, matches the long-term corrosion-inhibiting performance of its solvent-based counterpart, BR127 primer A nitrogen organic compound of high molecular weight, from 3,000 to many millions Proteins are made up of complex combinations of simple amino acids, and they occur in all animal and vegetable matter, but are also made synthetically They form a necessary constituent of foods and feeds, but are also used for many commercial products, but some proteins are highly poisonous The poison of the cobra and that of the jellyfish are proteins Different types of plant and animal life have different types of proteins At least 10 different proteins are known to be essential to human body growth and maintenance, but many others may have subsidiary functions since the amino acids are selective chelating agents, separating copper, iron, and other elements from the common sodium, calcium, and potassium compounds entering the system The simple proteins are made up entirely of the acids, but the complex or PROTEIN Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 762 PROTEIN conjugated proteins also contain carbohydrates and special groups, while the cystine of hair and wool also contains sulfur The constituent amino acids of the protein molecule are linked together with a peptide bond, and the linkage forms the backbone of the molecule, but the arrangement is not similar to the high polymers usually associated with plastics with one type of polymer, or group, repeating itself The linkage is formed by the loss of carbon dioxide rather than by the loss of water, as in plastics The simplest proteins are the protamines with molecular weights down to about 3,000 They are strongly basic, are water-soluble, and contain no sulfur Clupeine in herring and salmine in salmon and trout are examples The histones which occur in white blood corpuscles contain sulfur and are more complex The albumins of eggs and milk are soluble in water and coagulate with heat They also occur in plants, as in the leucosin of wheat Prolamines are vegetable proteins, as the zein of corn and the gliadin of wheat They are not an adequate human protein food without animal proteins Biologically, the edible proteins are classified as first-class and second-class, the first being from animal and the second from vegetable origin Meat and fish proteins are both complete, or first-class, proteins, but the digestibility of fish protein is slightly higher than that of beef protein, while oyster protein is high in growth-promoting value The synthesis of globulin and antibody formation for resistance to disease depends upon the utilization of various amino acids most readily obtained from first-class proteins The term protein isolates used in the food industry refers to proteins from soybean or other sources and containing 85% or more of protein Lysine, essential for human nutrition, is found in soy proteins, but it is also made synthetically as a water-soluble white powder, and is added to bakery products to raise the protein value to nearly that of animal protein Isoleucine, a bitter amino acid, occurs in casein It is an aminomethyl valeric acid which is fermented by yeast to amyl alcohol Sclero proteins, or albuminoids, contain much sulfur, are insoluble in water, resist hydrolysis, and are the most complex of the proteins They occur in skin, ligaments, horn, wool, and silk The complex, indigestible protein of poultry feathers, used for making brush fibers, is also broken down to produce digestible proteins used in feeds Glycine, or glycocoll, is an aminoacetic acid, H NCH COOH, formed by the hydrolysis of complex proteins and also made synthetically The methylated glycine, called betaine, occurs in plants and is obtained from sugar-beet molasses Hydrolyzed proteins are used in flavoring foodstuffs The Japanese condiment adjinimoto, made from wheat gluten, is largely Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PROTEIN 763 sodium glutamate, a salt of glutamic acid, C5H9O4, which also occurs in seeds and beets Monosodium glutamate is sold under trade names such as Zest of A E Staley Mfg Co and Ac’cent It is a white, crystalline powder derived from soybeans and sugar beets In small amounts it has no flavor, but intensifies the taste and flavor of foodstuffs This effect may be greatly increased by adding a chemical compound such as disodium inosinate or disodium guanylate to replace part of the glutamate Mertaste, of Merck & Co., is such a compound which enhances the flavor and acts as a synergist In large amounts the glutamates have an offensive odor and flavor and are considered toxic Insulin, used in medicine, contains glutamine, the half amide of glutamic acid, and also cystine, the disulfide of cysteic acid, an aminopropionic acid essential for nutrition Cystein is aminomercaptopropionic acid It is used with whey in bakery dough to react with yeast enzymes and give faster rising at lower temperatures Royal jelly, used in face creams, is a protein complex high in vitamin B It is a secretion of bees to nourish the egg of the queen bee, but has no apparent therapeutic value Wheat gluten, made from flour as a spray-dried powder, contains about 82% protein It is used as an additive to improve the texture and shelf life of baked goods Soybean protein is marketed as a highly refined, odorless, and tasteless powder for use in confectionery and other foods to retain freshness and add food value Proset-Flake is a soybean protein in flake form to give firmer texture Lupin, from the lupin bean, has more protein than soybean and more than twice the calcium of most nondairy foods The bean can be grown in poor soils and fixes nitrogen in the soil, reducing the need for chemical fertilizer Lupini Pasta is a lupin-based food product, and animal feed is a potential product Mushroom powder is used to add proteins to foodstuffs where the flavor is also desirable, as in sauces It is made by sheeting the pulped mushroom, Agaricus campestris, on a doubledrum drier and then grinding the sheet to a fine powder Animal protein factor, used in animal feeds, and marketed commercially in fish solubles, is an amino acid combination containing several vitamins It is also used in feeds for single-stomach animals, such as the hog, which cannot synthesize within themselves all the amino acids necessary for health It is also used in poultry feeds, as it contains the hatchability factor not adequately supplied by grains DL-methionine, of Dow Chemical Co., is a synthetic amino acid of composition CH SCH CH CH(NH )CO H, used in feeds for fattening poultry MPF granules, of General Mills, Inc., are granules of concentrated proteins, vitamins, and minerals for adding to bakery and meat products The whey from milk in powder form is added to bread to increase the protein content, and it also refines the texture of bakery Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 764 PROTEIN products In porous granule form it is used as a flow agent to add butter, margarine, or oils to bakery products as well as protein Kraflow, of Kraft General Foods, consists of whey granules which will absorb times their volume of oils Protein plastics are produced by the isolation of precipitation of proteins from animal or vegetable products and hardening or condensing into stable compounds that can be molded into sheet or fiber The oldest of the protein plastics is casein plastic which was used to replace bone for toothbrush handles and buttons It is still an important molding plastic, as it is tough and can be made in pastel shades, but it is more costly than many other molding plastics The proteins from soybean meal or other vegetable products are condensed with aldehydes or with various mineral salts or acids to form plastics These plastics are distinct from those made from the fatty acids of soybean or other oils Peanut fiber, under the name of Ardil, is made in England by precipitating the protein from peanut meal with an acid at low temperatures, so as not to denature the meal It is then dissolved in caustic soda and formed through spinnerets into a hardening bath The fiber is soft and resilient, moisture-absorbent as wool, moth-resistant, and it will dye easily It is mixed with wool in weaving fabrics Vicara is a protein fiber produced from the zein of corn The fiber is light yellow, soft, tough, and strong In fabrics it has the warmth of wool, is resistant to mildew, and withstands temperatures to 310°F (154°C) It can be blended with cotton, wool, or rayons Proteins obtained by alkaline extraction from cottonseed are also used to produce woollike fibers Azlon is a general name for protein fibers Chromated protein finishes that provide a corrosion-resistant undercoat on iron or steel are produced by coating the metal with casein or albumin and then impregnating with a chromate solution which hardens the film Enzymes are complex proteins consisting of hundreds of amino acids and are nature’s catalysts, generally in the presence of water In industry, the Austrian firm Chemie Linz employs a lipase to produce optically active 2-chloropropionic acid, a raw material for phenoxypropionic herbicides Peroxidase, an enzyme extracted from horseradish, works in organic solvents to convert suitable phenolic raw materials into plastics, such as Novolac An active isomer of ibuprofen, the anti-inflammatory drug, has been generated by the action of a protease enzyme on an ibuprofen precursor, an ester Durazyme, a protease of Novo Nordisk of Denmark, is widely used in detergents Several enzymes have been developed recently for the pulp paper and food-processing industries Polyzyme, of Novo Nordisk, and Xylanase, of Gencore International, reduce the need for chlorine in pulp and paper bleaching Resinase, a lipase of Novo Nordisk’s Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PUMICE 765 Japanese subsidiary and Jujo Paper Co of Tokyo, removes from pulp the triglyceride-heavy resin that can blemish paper products and stick to process equipment A lipase enzyme derived from Rhizopus delemar is used by Ajinomoto Co of Tokyo in a process that combines rapeseed and palm oils to produce vegetable cooking oil The cooking oil resists oxidation as well as palm oil does, but remains liquid at lower temperature—5°F (Ϫ15°C) versus 104°F (40°C) Using a reactor packed with immobilized lipase, Japan’s Fugi Oil Co produces a vegetable oil similar to cocoa butter PUMICE A porous, frothlike volcanic glass which did not crystallize due to rapid cooling, and frothed with the sudden release of dissolved gases Powdered or ground pumice is used as an abrasive for fine polishing, in metal polishes, in scouring compounds and soaps, and in plaster and lightweight concrete and pozzolanic cement In very fine powder it is called pounce, when used for preparing parchment and tracing cloth Pouncing paper is paper coated with pumice used for pouncing, or polishing felt hats Pumice is grayish white, and the fine powder will float on the surface of water The natural lump pumice contains 65 to 75% silica, 12 to 15 alumina, and to each of soda and potash It is produced chiefly in California and New Mexico Pumicite is a volcanic ash similar in composition to pumice, found in large beds in Nebraska, Kansas, and Colorado Its chief distinction is that it is fine-grained and has sharp edges suitable for abrasive purposes The natural material is dried, pulverized, and screened so that 98.8% will pass a 325-mesh screen Seismotite is a trade name for pumice used as an abrasive in scouring compounds Slag pumice, or artificial pumice, is made in Germany by treating molten slag with less water than is required for granulation It is used as an aggregate in lightweight concrete and as a heat insulator Obsidian will change into pumice when melted, but obsidian is a general name for volcanic glass and varies in composition It is an extrusive igneous rock that gets its glassy nature from its method of cooling, and some obsidian has a composition similar to that of granite It is colored black from magnetite, or brown to red from hematite Obsidian was used by the ancients for instruments and by the American Indians for arrowheads and knives Semitransparent, smoky-colored obsidian nodules of Arizona ore are called marekanite and are cut for Indian silver jewelry Hawaiian obsidian, or tachylite, also known as basalt glass, is a volcanic glass from Oahu, Hawaii It is jet-black, takes a fine polish, and is used for making ornamental articles The type of obsidian found in Oregon and California, known as perlite, is flashroasted to form a bubblelike, expanded material about 15 times the Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 766 PURPLEHEART original size which is crushed to a white, fluffy powder Perlite contains about 75% silica In California it has been called calite The powder has a density of only to 12 lb/ft3 (64 to 192 kg/m3) and is used in lightweight wallboard, acoustical tile, and insulation and as a lightweight aggregate in concrete Perlalex is the finely ground powder used for removing smears from drawing paper Rhyolite perlite of California is expanded to ovaloid particles of 23,000 to 33,000 in (590 to 840m) containing complete vacuums and having a density of only 0.78 lb/ft3 (12.4 kg/m3) This material has about 70% silica, 15 alumina, Fe2O3, 1.5 CaO, 2.75 Na2O, MgO, K2O, and water Grellex, of Great Lakes Carbon Corp., is expanded California perlite in fine particle size for use in plastics, adhesives, and insulation Other materials besides perlite may be expanded by heat Expanded clay is made from common brick clays by grinding and screening to 48 to 80 mesh and feeding through a gas burner at about 2700°F (1482°C) The ferric oxide is changed to ferrous oxide, liberating oxygen and CO2 Strong, light bubbles about 0.020 in (0.051 cm) in diameter are formed Kanamite is this material It has a density of 17 to 25 lb/ft3 (272 to 401 kg/m3) and is used as an aggregate for lightweight concrete The wood of several species of trees, notably Peltogyne paniculata of the Guianas The color of the wood is brown, the heartwood turning purple on exposure The grain is open and fine The wood has a density of about 53 lb/ft3 (849 kg/m3) and is very hard, strong, and durable It is used for machine and implement parts, inlays, furniture, and turnery PURPLEHEART PUTTY A mixture of calcium carbonate with linseed oil, with some- times white lead added It is used for cementing window glass in place and as a filler for patterns Litharge is often added to putty for steel sash Another putty for steel contains red lead, calcium carbonate, and linseed oil The dry pigment for putty, whiting putty, according to ASTM specifications, contains 95% calcium carbonate and tinting pigment White lead putty contains 10% or more white lead mixed with the calcium carbonate Federal specifications call for a minimum of 11% boiled or processed linseed oil with a maximum of 89% pigment as a white lead–whiting putty Putty powder is a mixture of lead and tin oxides, or a mixture of tin oxide and oxalic acid, or it may be merely an impure form of tin oxide It is used in enameling, for polishing stone and glass, and as a mild abrasive for dental polishes Caulking putty, used for setting window and door frames, is made of asbestos fibers, pigments, and drying oils, or with rubber or Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses PYRETHRUM 767 resins The older caulking compounds used in the building industry for sealing between window and door frames and masonry were made with drying oils and inert fillers, but they had poor adhesion and weathering qualities Caulking compounds are now composed of synthetics with usually a polysulfide rubber and a lead peroxide curing agent They are heavy pastes of 75 to 95% solids Koplac 1251-5, of Koppers Co., Inc., for automobile body patching and general utility putties, is a low-viscosity polyester resin with 32% styrene In putty formulations it is used with 50% talc and a catalyst It hardens rapidly at room temperature PYRARGYRITE An ore of silver, known also as dark ruby silver It is a sulfantimonite of silver, Ag3SbS3, containing 22.3% antimony and 59.8 silver It is found in various parts of Europe and in Mexico, Colorado, Nevada, and New Mexico It occurs in crystals or massive, and in grains Its Mohs hardness is 2.5 and specific gravity 5.85 The color is dark red to black, showing ruby red in thin splinters Proustite is another ore of silver occurring in silver veins associated with other metals It is found in the mines of Peru, Mexico, and Chile, and in Nevada and Colorado It is also called light ruby silver and is a sulfarsenite of silver of composition Ag3AsS3, containing theoretically 65.4% silver It occurs massive, compact, in disseminated grains The hardness is to 2.5, specific gravity 5.55, and the color is ruby red with an adamantine luster PYRETHRUM The dried flowers of several species of chrysanthemum, of which Chrysanthemum cinerariaefolium of Yugoslavia and Japan is the best known It is a slender perennial, about 15 in (38 cm) high, with daisylike flowers The powder is used as an insecticide chiefly in sprays The crude pyrethrum from Kenya contains 1.3% pyrethrin as compared with only 0.9% in the Japanese Persian powder is pyrethrum from the species C coccineum of southwestern Asia Lethane, of Rohm & Haas Co., is a synthetic aliphatic diacyanate used as a substitute for pyrethrum It is 30 to 40% more powerful than pyrethrum in insect sprays Pyrethrin contains pyrethronic acid and cyclopentane, (CH2)5 The active principles of natural pyrethrum flowers have been designated as pyrethrin and cinerin, and the synthetic material marketed is a homolog of cinerin In high concentration, it is more effective than natural pyrethrum A substitute for pyrethrum for the control of corn worms is styrene bromide, or bromostyrene, an oily liquid of composition C H CBr:CH Ryanodine, of composition C25H35NO9, is times more toxic than pyrethrin It is extracted from the stem wood of the ryania, a shrub of Trinidad Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses 768 PYROPHORIC ALLOYS PYROPHORIC ALLOYS Metals which produce sparks when struck by steel, used chiefly for gas and cigarette lighters The original pyrophoric alloy, or sparking metal, was known as Auer metal It was patented by Auer von Welsbach in 1903, and contained 35% iron and 65 mischmetal The French kunheim metal contained 10% magnesium and aluminum instead of iron A very durable alloy for cigarette lighters is zirconium-lead alloy containing 50% of each metal Titanium can replace part of the zirconium, and tin can replace part of the lead, but alloys with less than 25% zirconium are not pyrophoric The 50–50 alloy has a crystalline structure Some liquids are pyrophoric Trimethyl aluminum, Al(CH3)3, a colorless liquid made by sodium reduction of methyl aluminum chloride, is used as a pyrophoric fuel An aluminum silicate mineral found in North Carolina, used as a substitute for talc It is similar to talc in structure and appearance, but its composition, Al2Si4O10(OH)2, is more nearly like that of kaolin It is white, gray, or brown, with a pearly or greasy luster, specific gravity 2.8, and Mohs hardness to Compact varieties of the mineral are made into slate pencils and crayons A fine-grained compact rock mined in South Africa, composed of about 90% pyrophyllite, with rutile and other minerals, is called wonderstone and is used for tabletops and switchboard panels It is resistant to weathering, acids, and heat, and it can be planed, sawed, or turned in the lathe It then becomes harder on exposure Wonderstone is an ancient indurated clay resembling fireclay in which the colloidal matter has been destroyed by heat, pressure, and age Unfired refractory bricks are made of drypressed pyrophyllite They have high spalling resistance and not shrink Pyrax, of R T Vanderbilt Co., is pyrophyllite in fine, white powder of 100 mesh, with specific gravity of 2.6, used as a filler in rubber Silical is pyrophyllite from Newfoundland in fine-powder form as a dusting talc for rubber The Japanese employ great quantities of pyrophyllite in the making of firebrick, fireclay, and crucibles The mineral used averages of 86.7% pyrophyllite, 12.8 kaolin, and 0.5 diaspore PYROPHYLLITE The most common variety of silica It occurs mostly in grains or in masses of a white or gray color, but often colored by impurities Pure crystalline quartz is colorless and is called rock crystal Quartz usually crystallizes in hexagonal prisms or pyramids Many crystals are obtained from nodules, called geodes, which are rounded, hollow rocks with the crystals grown on the inside surface of the cavity These rocks range in size from very small to hundreds of QUARTZ Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website Materials, Their Properties and Uses QUARTZ 769 pounds The crystals are not always quartz, but may be grown from minor constituents of the rocks A geode in limestone usually has a shell of silica, and the interior crystals are of quartz or calcite, but some geodes contain crystals of gem quality containing metal coloring constituents The hard, rigid beta quartz crystals have a latticelike molecular structure in which each silicon atom is linked to four separate oxygen atoms, each oxygen atom being linked to two different silicon atoms The formula of quartz crystal, therefore, is (Si2O7)x, which is a pattern of the lattice, while the unit crystal of silica is SiO2 and the silica grains are cryptocrystalline The grains in sand are often less than 0.04 in (0.10 cm), but crystals up to 20 in (51 cm) have been found The specific gravity is 2.65 Pure crystals have a dielectric strength of 1,500 V/mil (59ϫ106 V/m) and a dielectric constant of 3.8, with good corona resistance Quartz crystals have the property of generating an electric force when placed under pressure and, conversely, of changing dimensions when an electric field is applied This property is termed piezoelectric A piezoelectric crystal is made up of molecules that lack both centers and planes of symmetry Many materials other than quartz have this property, such as rochelle salt and ammonium dihydrogen phosphate, but most are water-soluble or lack hardness The best quartz crystals are hexagonal prisms with three large and three small cap faces For electric use the crystals must have no bubbles, cracks, or flaws, and they should be free from twinning, or change in the atomic plane Piezoelectric quartz is used in microsensors that monitor emissions of spraying solvents to clean printed circuit boards Brazilian quartz crystals are cut into plates of different sizes to initiate and receive various frequencies on multiple-message telephone wires, and to obtain selectivity in radio apparatus Owing to its peculiar refractive powers, quartz crystal is also employed for the plates in polarization instruments and in lenses Quartz crystals for radio-frequency control are marketed in three forms: rough-sawed blanks, cut to specified angles; semifinished blanks, machine-lapped to approximate size; and electrically finished blanks, finished by hand and electrically tested Synthetic quartz crystals of large size and high purity and uniformity are grown from seed crystals suspended in an alkaline silica solution at high temperature and pressure The synthetic crystals are purified by imposing an electric current across the crystal at 932°F (500°C), which sweeps out the sodium and lithium impurities by electrolysis The addition of lithium nitride to the sodium hydroxide solution used in the hydrothermal growing process increases the Q value of the crystal to the range of natural quartz crystals These synthetic crystals are used in precision oscillators and highly selective wave filters Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies All rights reserved Any use is subject to the Terms of Use as given at the website ... ingredient, alloys including polycarbonate-ABS (PC-ABS), ABSpolyurethane (ABS-PUR), ABS-nylon, ABS-polysulfone, and ABS-polyvinyl chloride (ABS-PVC) Besides PC-ABS there are polycarbonate-polybutylene... cold-rolled metal is 91 compared with 78 for cold-rolled platinum Platinum-ruthenium alloy, with 10% ruthenium, has a PLATINUM ALLOYS Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)... (1093°C) and treated with water, high-pressure steam, and air The expanded slag formed is crushed to 0.375-in (0.95-cm) size, bulking 50 lb/ft3 (801 kg/m3) It is called TVA slag and is used for making