Ponting

Fig. Vni-11. ESCA spectrum of A1 surface showing peaks for the metal, A1(0), and for surface oxidized aluminum, Al(III) (a) freshly abraided sample (b) sample after five days of ambient temperature air exposure showing increased A1(III)/A1(0) ratio due to surface oxidation. (From Instrument Products Division, E. I. du Pont de Nemours, Co., Inc.)...

Pont A and Schwelger A 1994 Echo phenomena in electron paramagnetic resonance spectroscopy Appl. Magn. Reson. 7 363-403... 

The synthetic fiber industry as we know it began m 1928 when E I Du Pont de Nemours Company lured Professor Wallace H Carothers from Harvard University to direct their research department In a few years Carothers and his associates had pro duced nylon the first synthetic fiber and neoprene a rubber substitute Synthetic fibers and elastomers are both products of important contemporary industries with an economic influence far beyond anything imaginable m the middle 1920s... 

As the demand for rubber increased so did the chemical industry s efforts to prepare a synthetic sub stitute One of the first elastomers (a synthetic poly mer that possesses elasticity) to find a commercial niche was neoprene discovered by chemists at Du Pont in 1931 Neoprene is produced by free radical polymerization of 2 chloro 1 3 butadiene and has the greatest variety of applications of any elastomer Some uses include electrical insulation conveyer belts hoses and weather balloons... 

The strength of this bonding depends on the kind of ether Simple ethers form relatively weak complexes with metal ions but Charles J Pedersen of Du Pont discovered that cer tain polyethers form much more stable complexes with metal ions than do simple ethers Pedersen prepared a series of macrocyclic polyethers cyclic compounds contain mg four or more oxygens m a ring of 12 or more atoms He called these compounds crown ethers, because their molecular models resemble crowns Systematic nomencla ture of crown ethers is somewhat cumbersome and so Pedersen devised a shorthand description whereby the word crown is preceded by the total number of atoms m the ring and is followed by the number of oxygen atoms... 

DuponolC DuPontSilverlith Du Pont solution process DuPrene Dupril equation Durability... 

The thermal protection system of the space shutde is composed mainly of subliming or melting ablators that are used below their fusion or vaporization reaction temperatures (42). In addition to the carbon-carbon systems discussed above, a flexible reusable surface insulation composed of Nomex felt substrate, a Du Pont polyamide fiber material, is used on a large portion of the upper surface. High and low temperature reusable surface insulation composed of siHca-based low density tiles are used on the bottom surface of the vehicle, which sees a more severe reentry heating environment than does the upper surface of the vehicle (43). 

Throughout the remainder of this article the term homopolymer refers to Delrin acetal resin manufactured and sold by Du Pont the term copolymer refers to Celcon acetal copolymer resins (registered trademark of Hoechst Celanese Corporation). 

Nominal MI, g/10 min Hoechst Celanese Celcon Du Pont Delrin BASF Ultraform... 

Supply and demand statistics for 1988 for all regions of the wodd as compiled by SRI International are given in Table 5. The wodd producers of acetal resins and their aimual capacities are Hsted in Table 6 (29). Hoechst Celanese and Ultraform Corporation (a joint venture of Degussa and BASF) have aimounced capacity expansions in the United States to 77,000 t and 16,000 t, respectively both were due in place in 1990. Part of general capacity expansion plans, aimounced by Du Pont for completion in 1991, are beHeved to apply to acetal resins. 

E.I. du Pont de Nemours Company, Inc. Hoechst Celanese Corporation Ultraform Company Mexico... 

A = Aristech Chemical B = BP Chemicals Ce = Celanese Cy = CYRO Industries Do = Dow Chemical Du = Du Pont E = Eastman Chemical G = General Electric R = Rohm Haas S = Shell Chemical U = Union Carbide... 

Ma.nufa.cture. AU. manufacturers of butynediol use formaldehyde ethynylation processes. The earliest entrant was BASF, which, as successor to I. G. Farben, continued operations at Ludwigshafen, FRG, after World War II. Later BASF also set up a U.S. plant at Geismar, La. The first company to manufacture in the United States was GAF in 1956 at Calvert City, Ky., and later at Texas City, Tex., and Seadrift, Tex. The most recent U.S. manufacturer is Du Pont, which went on stream at La Porte, Tex., about 1969. Joint ventures of GAF and Hbls in Mad, Germany, and of Du Pont and Idemitsu in Chiba, Japan, are the newest producers. 

A second commeicial route to aciylonitiile used by Du Pont, Ameiican Cyanamid, and Monsanto was the catalytic addition of HCN to acetylene... 

---