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enc diols having an average polymer length of about 7.5 oxyethylene units. Properties: Cream-colored, soft, waxy or pasty solid at 25°C; faint, fatty odor and a slightly bitter, fatty taste, Soluble in toluene, acetone, ether, and ethanol. Nontoxic. Use: Emulsifier in bakery products. polyoxyethylene (40) monostearate (polyethylene gty- col stearate). A mixture of the mono- and distearate esters of mixed polyoxyethylene diols and corre sponding free glycols. The monostearate can be rep- resented as: H(OCH,CH;)OCOCi1Hs; (nis approxi- mately 40). Properties: Waxy, light tan, nearly odorless solid; congealing range 39-45°C; soluble in water, alcohol, ether, and acetone; insoluble in mineral oil and vege- table oils. Nontoxic, Grade: U.S.P. Uses: Ointments; emulsifier, surfactant; food additive. polyoxymethylene. Any of several polymers of form- aldehyde and trioxane. See acetal resin, polyoxypropylene diamine (POPDA). Any of six high molecular weight amines of low viscosity and vapor pressure, high primary amine content, and light color. Used as cross-linking agents in epoxy coat- ings, imparting high flexibility and adhesion at low temperatures. Other possible uses are in polyamide and polyurethane coatings, adhesives, elastomers and foams, as intermediates for textile and paper treatment, ‘and viscosity index improvers in lube oils. polyoxypropylene ester. See polypropylene glycol ester. Polyoxypropylene-glycerol adduct. One of several con- densation polymers of propylene oxide and glycerol, with molecular weights in the range 1000 to 4000. Clear, stable, almost colorless, noncorrosive liquids. Uses similar to those of polypropylene glycol (q.v.). “Poty-pate."™* Trademark for pale, hard, thermo- lastic resins; 40% dimeric resin acids; acid number 45, USDA’ color WG; softening point 102°C. vailable in solid and flake forms. Uses: Adhesives, lacquers, varnishes, printing inks. polypeptide (peptide). The class of compounds com- posed of acid units chemically bound together with amide linkages (CONH) with climination of water. A polypeptide is thus a polymer of amino acids, forming chains that may consist of several thousand amino acid residues. A segment of such a chain is as follows: H ° rR? H ° Rr H ° Reh fF fed ffl i 1 I 7 NY Swe NY Sw NY NX ro ' ot i I, R a ° R a ° R The sequence of amino s in the chain is of critical importance in the biological functioning of the pro- tein, and its determination is one of the most dil It problems in molecular biology. The chains may be relatively straight, or they may be coiled or helical. In the case of certain types of polypeptides, such as the keratins, they are cross-linked by the disulfide bonds of cystine. Linear polypeptides can be regarded at protcins, See also protein; polyamide; keratin. polypfienylene oxide. See “PPO.” POLYPROPYLENE- polyphenylene triazole {—C,H.—C:Ns(CGoHs)—]. A polymer stated to be serviceable up to S0O*F for ilms, coatings, adhesives, and lamination. “Polyphos."“ Trademark for a water-soluble glassy sodium phosphate of standardized componten, (NaigPuGy) anal ing 63.5% PO; (ratio of Na,O:P,0, is 1.2:1). It is closely similar to a sodium hexametaphosphate and sodium tetraphosphate; fre- quently the three names are used interchangeably, Grades: Ground; walnut-size to pea-size lumps. Containers: 100-Ib bags; 100-, and 350-Ib drums. Uses: Boiler water compounds; detergents; textiles; leather tanning; photographic film developing. de- flocculation of clays; flotation and desliming of minerals; dispersion of pigments; paper processing: industrial and municipal water treatment. polyphosphazene, See phosphazene. polyphosphoric acid Hy.2P, Orow, for n> 1. Any of series of strong acids, from pyrophosphoric acid, H.P30; a = 2), through metaphosphoric acid (large values of n). Properties: Viscous, water-white liquid; water-soluble; does not crystallize on standing. Hygroscopic. The commercial acid is a mixture of orthophosphoric acid with pyrophosphoric. triphosphoric and higher acids and ts sold on the vasis of its calculated con- tent of HyPO,, as, for example 115%. Superphos- Phoric acid is a similar mixture sold at 105% H)PQ.. ese acids revert slowly to orthophosphoric acid on dilution with water. Hazard: Moderately toxic by ingestion; strong irri- tant. Uses: Dehydrating, catalytic and sequestering agents; for metal treating: many applications where a con- centrated monoxiaing acid is needed; laboratory reagent. See also phosphoric acid. polypropylene (C)Hs).. A synthetic crystalline thermo- plastic polymer, with molecular weight of 40,000 or more. Note: low molecular weight polymers are also known which are amorphous in structure, and used as gasoline additives, detergent intermediates, greases, sealants, and lube oil additives: also available as 2 high-melting wax. Derivation: Polymerization of propylene with a stereo- specific catalyst (q.v.) such as aluminum alkyl. Properties: Translucent white solid; specific gravity 0.90; m.p. 168-171°C; tensile strength 5000 psi; flex- ural strength 7000 psi: usable up to 250°F. Insoluble in cold organic solvents; softened by hot solvents. Maintains Strength after repeated flexing. Degraded by heat and light unless protected by antioxidants, Readily colors ood electrical resistance; low wa- ter absorption and moixture permeability; poor im- act strength below 15°F, not attacked by fungi or acteria, resists strong acids and alkalies up to 140°F; but is attacked by chlorine, fuming nitric acid, and other strong oxidizing agents. Combustible, but slow- burning. Nontoxic. Fair abrasion and good heat re- sistance if Properly modified. Can be chrome-plated, injection- and blow-molded, and extruded. Forms: Molding powder, extruded sheet; cast fitm (1 to 10 miis); textile ‘staple and continuous filament yarn, fibers with diameters from 0.05 to 1 micron and fiber webs down to 2 microns thick; low-density foam, Uses: Packaging film; molded parts for automobiles, appliances, housewares, etc.; wire and cable coating: Superior numbers refer to Manufacturers of Trade Mark Products. For page number see Contents. i Ses ee ees