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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 58 (1962), S. 1283-1291 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mechanism of the thermal degradation of polytetrafluoroethylene is investigated. It is shown that the chain transfer reaction should not be ignored and that a reasonable explanation for the observation that monomer is almost the exclusive product of vacuum thermal degradation is the rate of diffusion and volatilization of larger fragments from the polymer. Diffusion of tetrafluoroethylene and hexafluoropropylene through polytetrafluoroethylene was studied. The diffusivities are 72 and 39 × 10-10 cm.2/sec. for C2F4 and C3F6, respectively, at 24°C. An apparatus for measuring the weight and temperature of degrading polymers under vacuum is also described.
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 14 (1993), S. 1379-1381 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: After preparative nondenaturing isoelectric focusing in a Rotofor of 1 mL human serum which showed on two-dimensional electrophoresis a monoclonal kappa light chain pI 〈 5.0, the monoclonal kappa light chain was identified in the tubes with pH 7.29 - pH 6.96, indicating that the chain was not free and was most likely part of an immunoglobulin molecule. The combined fractions of the Rotofor were concentrated back to 1 mL and aliquots were separated by two-dimensional electrophoresis, followed by Western blotting. Enzyme immunoassay of the blot with A′ human IgG (γ chain specific) revealed a monoclonal heavy chain at a molecular size of approximately 100 kDa. Diffuse areas at 50 kDa (the attributed size of γ heavy chain), 100 kDa, and 150 kDa were stained also, but the strong, restricted (picket fence) bands indicating a monoclonal pattern were at 100 kDa. The monoclonal light chain appears to be part of a large or dimeric IgG molecule.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 13 (1992), S. 440-444 
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Two-dimensional (2-D) electrophoresis was performed on 24 serum samples from patients diagnosed with monoclonal gammopathies. These samples had been shown to have a homogeneous immunoglobulin (M component) by zone electrophoresis and immunofixation. Using 2-D electrophoresis, the nature of this aberrant protein was further analyzed. It has been presumed that the sharp, dark stained band identified by immunofixation was the production of a monoclonal immunoglobulin. The increased resolution afforded by 2-D methodology reveals several different patterns. On 2-D electrophoresis, a monoclonal antibody has a unique pattern. It consists of 3 to 6 strong, restricted heavy chain bands and a single distorted light chain spot. The 3-6 bands are microheterogeneity of the isoelectric point, attributed to posttranslational glycosylation and/or amidation/ deamidation. Analysis by 2-D electrophoresis indicated only 5 samples with a true monoclonal pattern. All but 2 of the samples clearly had aberrant immunoglobulin, but interpretation of the pattern would suggest the protein is other than a fully synthesized monoclonal antibody. The samples showed the following: a monoclonal heavy chain pattern with multiple distorted light chain spots, only an aberrant light chain area, only an aberrant heavy chain, and only a polyclonal increase. Several IgG gammopathies had, in addition, concentrations of gamma heavy chain at a reduced size (34 kDa).
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 1505-1515 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polybis(p-isopropylphenoxy)phosphazene was treated thermally at 100, 135, 200, and 300°C. The resulting reductions in weight-average molecular weights were monitored by gel-permeation chromatography, and the experimental observations led to the adoption of a random chain-scission model. An effective energy of activation and entropy of activation were calculated for the degradation process, and these values were found to be consistent with a random-scission model. The analysis was, in part, based on a computer-simulated first-order degradation model. This polymer showed higher thermal stability than previously reported polyaryloxyphosphazenes.
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Synthesis of 3,3′-bis(4-[3-ethynylphenoxy]phenyl)-7,7′-bis(phenylethynyl)-2,2′-diphenyl-6,6′-biquinoxaline (I) was accomplished by the reaction of 2,2′-bis(phenylethynyl)-5,5′-diaminobenzidine (II) and 4-(3-ethynylphenoxy)benzil. Thermal analysis of I indicated a softening temperature of 107°C, followed by an exotherm above 150°C that corresponded to a independent crosslinking reaction of the terminal acetylene groups and an intramolecular cycloaddition (IMC) reaction of the 2,2′-bis(phenylethynyl)biphenyl moieties. In the synthetic work substantial improvements were made in the synthesis of II. The sample of I was cured at 200°C and the maximum partially cured transition temperature attained was 280°C. A sample of 3,3′-bis(4,[3-ethynylphenoxy]phenyl)-2,2′-diphenyl-6,6′-biquinoxaline (IV) was similarly tested as a model without IMC capability and its corresponding value was 250°C. The difference between these two values is discussed briefly.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 361-369 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of polyaryloxyphosphazene copolymers with the general formulas [NP(OC6H5)(OR)]n and [NP(OC6H4-4-OCH3)(OR)]n, where R = C6H4-4-CH3, C6H4-4-C2H5, C6H4-4-isoC3H7, C6H4-4-sec-C4H9, C6H4-4-tert-C4H9, C6H4-4-OCH3 or C6H4-4-OC4H9, have been prepared under anhydrous conditions. Copolymers as well as selected homopolymers were prepared by the reaction of polydichlorophosphazene with appropriate sodium aryloxides. Each of the polymers was characterized by elemental analysis, infrared spectroscopy, gel-permeation chromatography, and differential scanning calorimetry. Elemental analysis established the empirical formula for the polymers and showed that there were no residual P—Cl bonds left on the polymer backbone. Infrared spectroscopy indicated the presence of a phosphorus-nitrogen backbone with two aryloxy groups bonded to each phosphorus atom. The copolymers examined exhibited molecular weights of above 1 × 106. Polyaryloxyphosphazene copolymers were examined by differential scanning calorimetry and compared to several of the corresponding homopolymers. Glass transition temperatures ranged between -34 and +44°C for the polymers. The Kelley-Bueche equation was used to predict the glass transition temperatures of the copolymers. Close agreement was found between calculated and experimental values for most of the systems examined.
    Additional Material: 4 Tab.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 665-677 
    ISSN: 0021-8995
    Keywords: 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 , Physics
    Notes: An acetylene terminated sulfone resin mixture, prepared under contract for the Air Force, was subjected to a fairly extensive compositional analysis. Monomer, dimer, higher oligomers, solvents, and anomalous side products of synthesis were isolated, identified, and quantified using separatory procedures such as column chromatography and thin film flash distillation, in conjunction with techniques of chemical analysis such as infrared and nuclear magnetic resonance spectroscopy, size exclusion chromatography, and elemental analysis. By these means we were able to precisely characterize the resin mixture and, by so doing, identify some side products of synthesis; most notably, a class of abnormal coupling product able to chelato palladium (a catalyst used in acetylation of the resin) and, therefore, accelerate subsequent acetylene polymerizations in the resin mixture.
    Additional Material: 10 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 679-691 
    ISSN: 0021-8995
    Keywords: 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 , Physics
    Notes: The kinetics and thermodynamics of the cure and post-cure reactions of an acetylene terminated sulfone (ATS) resin mixture and pure fractions from that mixture were studied using differential scanning calorimetry. Thermal stabilities were measured by programmed thermogravimetry under helium, and oxidative stabilities using isothermal thermogravimetry in air. Microstructural changes accompanying the cure reaction were identified using infrared spectroscopy. Early products of thermal degradation were trapped for identification and quantitative analysis using the technique of sub-ambient thermal volatilization analysis. We found that glass transition temperatures increase with crosslink density in the resin, that oxygen is able to copolymerize or couple with the polyenes to produce peroxides or hydroperoxides (respectively) which subsequently decompose to form terminal alcohols on the polyene, that weight loss in air at 600°F is an oxidative process that is insensitive to resin crosslink density, and that sulfone functionality constitutes the thermal weak link in the ATS resin system.
    Additional Material: 14 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 1395-1400 
    ISSN: 0021-8995
    Keywords: 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 , Physics
    Notes: Isothermal dilatometric measurements on quenched, plasticized PVC have been made at a series of temperatures, and a mathematical expression has been obtained to described the specific volume as a function of time. The results of these measurements, along with those obtained using differential scanning colorimetry (DSC) for the change in enthalpy accompanying annealing, clearly show a change in the character of the annealing process with rising temperature; but the underlying molecular kinetic mechanism apparently remains unchanged.
    Additional Material: 3 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 116 (1968), S. 96-106 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Das Verhalten von Polyvinylpyrrolidon in Wasser und in Salzlösungen wurde durch Messungen der Wärmekapazitäten, der spezifischen Volumina und der reduzierten Viskositäten untersucht. Die Lösungswärmen von PVP in Wasser liegen bei ungefähr -4 kcal/mol Monomereneinheit, während sie im Falle der Salzlösungen niedriger sind. Die Resultate werden im Lichte des Mechanismus für den Stabilisierungseffekt. den hydrophile Kolloide auf hydrophobe ausüben, diskutiert. Es wurde kein Hinwels für die Existenz von „strukturiertem Wasser“ in der Nähe der Polymeren gefunden; somit scheint es nicht möglich zu sein, die Stabilisierung des Kolloids durch Hydrathüllen von „eisähnlichem Wasser“ zu erklären. Es wird ein Stabilisierungsmechanismus vorgeschlagen, der auf einer Erhöhung der Mischungswärmen des Kolloids in Wasser beruht.
    Notes: The properties of polyvinylpyrrolidone, in water and salt solutions, are examined by measuring the heat capacities, specific volumes and reduced viscosities. The heats of solution in water are of the order of -4 kcal per mole of monomer unit, they are decreased in the presence of salts. The results are discussed in terms of the mechanism of the stabilizing effect of hydrophylic colloids on hydrophobic ones. No evidence is found in terms of the existence of more “structural water” in the vicinities of the polymer molecules; this is taken to imply that stabilization is not effected through hydration multilayers of “ice-like water”. A mechanism of stabilization based on the signs and magnitudes of the heats of solution of colloids in water is proposed.
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