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  • 1990-1994  (5)
  • 1975-1979  (19)
  • 1930-1934  (1)
  • Chemistry  (25)
  • 1
    Electronic Resource
    Electronic Resource
    Reinforcement of amorphous thermoplastics by blending with a para-linked aromatic LC-polyester (1990)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 1 (1990), S. 143-150 
    Details
    ISSN: 1042-7147
    Keywords: Reinforcement ; Amorphous ; Matrix ; LC-polyester ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The preparation and the mechanical properties of binary blends of amorphous thermoplastics and a para-linked liquid crystalline polyester, which is expected to act as a reinforcement, are reported. The LC-polyester has the advantage that it is soluble in common organic solvents, that it has a low transition temperature, and that it does not crystallize readily. Polycarbonate, polystyrene, poly(methyl methacrylate), and poly(ether sulfone) were selected as matrix materials. Most of the films cast from the blends turned out to be turbid and thus phase separated, the sizes of the dispersed phases ranging between 0.2 μm (in polycarbonate) and 1 μm (in polystyrene).The LC-polyester causes a substantial increase of the stiffness in blends with polycarbonate, poly(methyl methacrylate), and poly(ether sulfone) and almost no increase in the case of polystyrene. These differences are attributed to the particular magnitudes of the strength of the phase coupling between the matrix and the dispersed phase, which is controlled by their compatibility.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1990.220010204
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  • 2
    Electronic Resource
    Electronic Resource
    Excimer laser micromachining (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 87-92 
    Details
    ISSN: 1057-9257
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The machining of several materials such as polymers, metals and ceramics using excimer lasers (193, 248 and 308 nm) was investigated. By photoablation, micrometer resolution can be achieved for polymers if the wavelength and fluence are chosen properly. High-definition processing of metals is complicated by the occurrence of surface melting. An interaction between the ablation plume and the walls of the laser-drilled holes leads to hole widening in the case of polymers at high fluences. For small structures (〈100 μm) all materials investigated show a size-dependent ablation rate. This effect has to be taken into account if a precise ablation depth is required for a pattern with structures of different sizes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020111
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  • 3
    Electronic Resource
    Electronic Resource
    On the linear viscoelastic limit of polymers - exemplified on poly(methyl methacrylate) (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 883-887 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The linear viscoelastic limit of poly(methyl methacrylate) (PMMA) is established on the basis of the Reiner-Weissenberg criterion of strength. The obtained limit is not simply a “strainlimit” or a “stress-limit” but a function of both strain and stress, an energetical limit. In stress-strain representation the limit is independent of time and temperature, which means that the linear or non-linear behavior of the material depends only on the actual values of strain and stress. Some experimental data obtained on PMMA confirm the theory.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760191212
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  • 4
    Electronic Resource
    Electronic Resource
    Ylidenmalonitrilphosphine (NC)2C=C(X)PRR′Professor Gerhard Fritz zum 60. Geburtstage gewidmet (1979)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 459 (1979), S. 131-139 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Ylidenmalonitrilphosphines (NC)2C=C(X)PRR′Ylidenmalonitrilphosphines of the general formula (NC)2C=C(X)PRR′ (X = Alkyl, Cl, NH2, PRR′; R = Ph, R′ = Ph, H) are prepared under different conditions from (NC)2C=C(X)Cl (X = Alkyl, Cl, NH2) and prim. or sek. phosphines and their monosubstituted alkali or trimethylsilyl derivatives respectively. The synthesis as well as the behaviour of (NC)2C=C(X)PRR′ are compared with the corresponding oxygen analogues of the type O=C(X)PRR′. The structure of the title compounds are elucidated by investigation of their mass, i.r., and n.m.r. spectra.
    Notes: Ylidenmalonitrilphosphine der allgemeinen Formel (NC)2C=C(X)PRR′ (X = Alkyl, Cl, NH2, PRR′; R = Ph, R′ = H, Ph) lassen sich unter verschiedenen Reaktionsbedingungen aus (NC)2C=CXCl (X = Alkyl, Cl, NH2) und prim. oder sek. Phosphinen bzw. deren monosubstituierten Alkali- sowie Trimethylsilylderivate herstellen. Sowohl Synthese als auch Eigenschaften der Ylidenmalonitrilphosphine werden mit den Sauerstoffanaloga des Typs O=C(X)PRR′ verglichen und IR-, NMR- sowie massenspektroskopisch charakterisiert.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19794590114
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  • 5
    Electronic Resource
    Electronic Resource
    Einfluß von HCl und Cl2 auf die Hochtemperaturkorrosion des 2 1/4 Cr 1 Mo-Stahls in Atmosphären mit hohen Sauerstoffdrücken (1990)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 41 (1990), S. 303-307 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Influence of HCl and Cl2 on high temperature corrosion of 2 1/4Cr 1 Mo Steel in atmospheres with high oxygen pressuresThe oxidation of the 2 1/4 Cr 1 Mo steel was investigated at 773 K in oxidizing He-O2-HCl atmospheres. The addition of HCl to He-O2 atmospheres leads to accelerated oxidation rates. Below porous and cracked oxide scales condensed chlorides are formed. At low HCl pressures 0-1000 vppm the “active oxidation” is determining the corrosion process; i.e. oxidation of evaporating chlorides within the oxide scale. For higher HCl contents 1000-3000 vppm the corrosion behaviour changes to paralinear; i.e. simultaneous parabolic oxide growth and linear mass loss by chloride evaporation.
    Notes: Die Oxidation des 2 1/4Cr1Mo-Stahls in oxidierenden He-O2-HCl-Atmosphären bei 773 K wurde untersucht. Der Zusatz von HCl zu He-O2-Atmosphären führt zu stark beschleunigter Oxidation. Unter porösen und rissigen Oxidschichten bilden sich feste Chloride. Bei niedrigen HCl-Drücken 0-1000 vppm bestimmt „aktive Oxidation“ den Korrosionsprozeß; d.h. Oxidation flüchtiger Chloride innerhalb der Oxidschicht. Bei höheren HCl-Drücken 1000-3000 vppm erfolgt ein Übergang zum paralinearen Korrosionsverhalten, d.h. gleichzeitiges parabolisches Oxidwachstum und lineare Massenabnahme durch das Abdampfen von Chloriden.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19900410602
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetik der Chlor-Addition an aliphatische Olefine (1975)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 317 (1975), S. 53-61 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Addition von Chlor an 24 Olefine verschiedener Struktur wurde in Methanol als Lösungsmittel bei etwa -70°C nach der Methode der Konkurrenzreaktion kinetisch untersucht. Um eine radikalische Reaktion auszuschließen, wurde in Gegenwart von Sauerstoff und unter Lichtausschluß gearbeitet.Die relativen Reaktionsgeschwindigkeiten der 22 untersuchten offenkettigen aliphatischen Olefine lassen sich befriedigend mit der dreiparametrigen und der fünfparametrigen TAFT-Gleichung korrelieren, doch deuten die Ergebnisse (ϱ* = -1,29 bzw. ϱ1* = -1,26 und ϱ2* = -1,16) auf einen Übergangszustand, der keine Ähnlichkeit mit einem offenkettigen Carbeniumion besitzt.
    Additional Material: 6 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19753170106
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  • 7
    Electronic Resource
    Electronic Resource
    Diels-Alder-Reaktionen. VII. Über die Isomerisierung von 2-Vinylbicyclo[2,2,1]hepten-(5) (1977)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 77-82 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Diels-Alder Reactions. VII. The Isomerization of 2-Vinylbicyclo[2,2,1]hept-5-eneThe isomerization of exo/endo-2-vinylbicyclo[2,2,1]-hept-5-ene in the presence of Na/Al2O3 rapidly gives the thermodynamic equilibrium between exo- and endo-2-vinylbicyclo-[2,2,1]hept-5-ene and cis- and trans-2-ethylidenbicyclo[2,2,1]-hept-5-ene. Far more slowly vinylnortricyclene is formed, which enriches to an equilibrium concentration of about 75% at 60°C. The dependence of equilibrium constants of isomerization on temperature allows the calculation of enthalpies and entropies of isomerization.
    Notes: Die Isomerisierung von exo/endo-2-Vinylbicyclo[2,2,1]hepten-(5) in Gegenwart von Na/Al2O3 führt schnell zur Einstellung des thermodynamischen Gleichgewichtes zwischen exo- und endo-2-Vinylbicyclo[2,2,1]hepten-(5) und cis- und trans-2-Äthyliden-bicyclo[2,2,1]-hepten-(5). Wesentlich langsamer wird Vinylnortricyclen gebildet, das sich bis zu einer Gleichgewichts-konzentration von etwa 75% bei 60°C anreichert. Die Temperaturabhängigkeit der Isomerisierungs-gleichgewichtskonstanten gestattet die Berechnung der Isomerisierungsenthalpien und -entropien.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19773190112
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  • 8
    Electronic Resource
    Electronic Resource
    Nachweis von anti-Markownikow-Produkten bei der Acetoxychlorierung von 1-Alkenen (1975)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 317 (1975), S. 874-876 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19753170523
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  • 9
    Electronic Resource
    Electronic Resource
    Die Photochlorierung des Pentans (1977)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 775-784 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The Chlorination of PentaneThe kinetics of the chlorination of pentane were studied and the concentration course of the mono- and dichlorpentanes calculated with the aid of an analog-computer. The relative reactivities of different C—H-bonds were determined from the rate constants. The structure of the diastereomeres formed is discussed.
    Notes: Die Kinetik der Pentanchlorierung wurde untersucht und der Konzentrationsverlauf der Mono- und Dichlorpentane am Analogrechner nachgebildet. Aus den erhaltenen Geschwindigkeitskonstanten wurden C—H-Reaktivitäten ermittelt. Die Struktur der auftretenden Diastereomeren wird diskutiert.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19773190513
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zur intramolekularen C—C-Verknüpfung von Dienen durch Basenkatalyse. III. [1] Cyclisierung von Diallylaminen (1977)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 319 (1977), S. 979-986 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Attempts to Intramolecular C—C-Connexions of Dienes by Base-catalysis. III. Cyclization of Diallyl AminesDiallyl alkyl amines 1 are isomerized to the corresponding dipropenyl alkyl amines with potassium on alumina catalyst. The trans, trans-isomers are thermodynamically prefered. If the alkyl group in the diallyl alkyl amines is replaced by an electron-attracting group a cyclization to tetrahydropyridines takes place. The base-catalysed isomerization of diallyl ether 3 does not give a cyclic product. Diallyl sulfide 4 can be isomerized to 5-methyl thiacyclohexen-(2) 4a.
    Notes: Diallylalkylamine 1 lassen sich mit Kalium auf Aluminiumoxid zu den jeweiligen Dipropenylaminen isomerisieren. Das thermodynamische Gleichgewicht liegt dabei völlig auf der Seite der trans, trans-Isomeren. Wird der Alkylrest in den Diallylalkylaminen durch eine elektronenanziehende Gruppe ersetzt, so erfolgt Ringschluß zu Tetrahydropyridinen. Während Diallyläther 3 unter den Bedingungen der Basenkatalyse kein Ringschlußprodukt bildet, läßt sich Diallylsulfid 4 zu 5-Methylthiacyclohexen-(2) 4a isomerisieren.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19773190620
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