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  • Polymer and Materials Science  (9)
  • Wiley-Blackwell  (9)
  • American Association for the Advancement of Science (AAAS)
  • American Chemical Society
  • 1990-1994  (9)
  • 1935-1939
  • 1994  (4)
  • 1992  (3)
  • 1991  (2)
Collection
Publisher
  • Wiley-Blackwell  (9)
  • American Association for the Advancement of Science (AAAS)
  • American Chemical Society
Years
  • 1990-1994  (9)
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1589-1600 
    ISSN: 0887-624X
    Keywords: reactivity ; amines ; functional polymers ; anhydride ; carbonxylic acid ; crosslink ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive melt processing of different types of diamines with polyethylene containing carboxylic acid groups and polystyrene containing anhydride groups was carried out. The reactivity of primary, secondary, and tertiary diamines with these acid polymers was determined using various techniques. Molecular weight increases due to crosslinking were observed through (1) changes in the torque during the reactive processing, (2) decrease in melt flow indices, and (3) decrease in solubility of the reaction products. The chemical compositions of the reaction products were examined by Fourier transform infrared (FTIR) spectroscopy. Thermal analysis using differential scanning calorimetry (DSC) was carried out to determine the crystallization behavior, glass transition temperatures, and thermal stabilities of the reaction products. Results show that the primary amine is the most reactive towards carboxylic acid or anhydride groups followed by the secondary and then the tertiary amine. Anhydride groups on polymers are of higher activity towards secondary or primary amino groups than carboxylic acid groups in the nucleophilic acyl substitution reactions. Reaction products crosslinked with the primary diamine are less stable than their parent acidic polymers. On the other hand, crosslinking with the secondary or tertiary diamine gives products with higher thermal stability than the parent acidic polymers. The formation of reversible and irreversible crosslinks with different types of diamines is also reported. © 1992 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 1691-1702 
    ISSN: 0887-624X
    Keywords: grafting ; basic functionalization ; free radical polymerization ; methacrylate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The grafting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) onto two model hydrocarbons, squalane and n-eicosane, and to linear low density polyethylene (LLDPE) has been investigated. The results of the study indicate that a high reaction temperature, 160°C, and a low concentration of monomer, less than 0.3 M, are optimum conditions for the grafting reaction. Reaction products, which consisted of grafted hydrocarbons and poly(DMAEMA), were separated by solvent extraction and vacuum distillation; samples were then analyzed by NMR and FTIR spectroscopy and size exclusion chromatography. 1H-NMR spectroscopy indicates that grafted squalane contained approximately 6 DMAEMA units per squalane residue. 1H- and 13C-NMR and molecular weight studies strongly suggest that the grafts onto the model hydrocarbons consist of single DMAEMA units. Results of the melt grafting of DMAEMA onto LLDPE show that the grafting efficiency and degree of grafting are substantially lower than were expected from the model system. © 1994 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 783-788 
    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: Hydrogles, sensitive to pH, were prepared by copolymerizing 2-hydroxyethyl methacrylate (HEMA) with 2-dimethylaminoethyl methacrylate (DMA). The mole fraction of the DMA monomer present during synthesis was fixed at 0.3, while the volume fraction of total monomer varied from 0.29 (I) to 1.0 (II). Swelling equilibria were measured in citrate of phosphate buffer for pH from 3.0 to 7.6 Swelling of the hydrogels depends on the volume fraction monomer present during synthesis, solution, pH, and identity of the buffer, Hydrogel I reached a four-fold larger swelling ratio (g swollen hydrogel/g dry hydrogel) in pH 3.0 citrate buffer, as compared to hydrogel II. Experimental results are interpreted on the basis of ideal Donnan equilibria. © 1994 John Wiley & Sons, Inc.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 2167-2177 
    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: Blends of a styrene-maleic anhydride copolymer (SMA) with polyethlene (PE) or polyethylene melt grafted with tertiary (PE-g-DMAEMA) or secondary (PE-g-tBAEMA) amino methacrylate were prepared by blending in a batch melt mixer. The morphology of these blends at various compositions was examined with a scanning electron microscope (SEM) and related to their tensile and impact properties. The SMA/PE blends are found to have the typical coarse morphology of incompatible blends and poor mechanical properties, while their reactive conterparts, SMA/PE-g-DMAEMA or SMA/PE-g-tBAEMA blends, show finer morphology and modestly improved tensile and impact strength. This was attributed to chemical interaction of the acidic anhydride and the basic amino groups. The greater improvement in morphology for SMA/PE-g-tBAEMA than for SMA/PE-g-DMAEMA suggests a stronger interaction between the secondary amino groups and the anhydride groups, possibly with the formation of SMA-g-tBAEMA-g-PE graft polymer through amide covalent bonds. The amide formation appears to occur at the interfacial region in the blends and is too little to be detected by Fourier transform infrared (FTIR) spectra. However, differential scanning calorimeters (DSC) and the viscosity measurements indicate crystallinity and molecular weight changes for the SMA/PE-g-tBAEMA blends, supporting an argument for the formation of SMA-g-tBAEMA-g-PE grafts at the phase interface.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 22 (1994), S. 308-313 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The interfacial region of a Sigma fibre/Ti-6Al-4V composite has been studied by Auger/EDX microscopy. The SiC fibre has a duplex coating consisting of an inner layer of C and outer TiBx layer. Point analyses, line scans and images were acquired from the fibre/matrix interface region for a specimen taper sectioned at 10° to the fibre axis and a sample fractured in situ along the fibre length. Fracture of the composite reveals the presence of a brittle B rich oxide layer probably of the form TixByO at the boride coating/matrix interface. The fracture path occurs either through this oxide or the graphitic carbon layer. C is shown to have diffused through the entire boride coating. B diffuses from the TiBx layer into the matrix, forming TiB at the interface. The presence of excess boron in the coating and the strong affinity of B for O are proposed as the main driving forces for oxide formation at the TiBx/matrix interface.
    Additional Material: 6 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 22 (1994), S. 167-170 
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: A new method for the determination of N/Ti ratio for TiNx samples has been proposed. High energy resolution Auger spectra recorded of the Ti L3M23M45 peak have shown that on nitridation of Ti to TiNx a second peak, labelled the L3M23Hybrid peak, emerges at 3.9 eV below the L3M23M45 peak in the raw data, which grows with the grade of nitridation. After a simple Shirley background correction a linear dependence between the ratio of the L3M23Hybrid/L3M23M45 peak height of the raw data and the N/Ti ratio was found. This relation can be used directly to evaluate the nitrogen content of an unknown TiNx compound by recording only the Ti L3M23M45 region. The changes of the L3M23M45 peak structure have been interpreted and compared with earlier DOS calculations for Ti and TiN. Good agreement between experiment and theory was found, enabling a discussion of the valence electronic structure changes for Ti on nitridation.
    Additional Material: 4 Ill.
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  • 7
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An estimate of the detonation pressure of carbohydrate-metal composite explosives has been obtained experimentally by use of carbon resistor pressure gauges mounted in the wall of the confining tubes. The composite explosives were formulated from a pharmaceutical mixture of 10/90 nitroglyccrin/ß-lactose by weight, and was rendered detonable by inclusion of flaked aluminum and both flaked aluminum and ammonium perchlorate. The detonation pressure of the nitroglyccrin/ß-lactose mixture with 10 percent aluminum by weight was approximatcly 1.1 GPa. The incorporation of 30 percent ball-milled ammonium perchlorate to this formnlation increased the detonation pressure to 12.2 GPa. These pressures must be considered as estimates of the true detonation pressure, because of (a) the suspected non-ideality of the detonation state of these explosives, (b) the statistical nature of the response of the gauges, and (c) possible inconsistencies in the interpreatation of the gauge records. It is recommended that a number of gauges be used in a given experiment, and the results be averaged as one means of cireumventing the above difficulties.
    Additional Material: 3 Ill.
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  • 8
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The state of the art relative to the measurement of shock and detonation pressures of the magnitude generaled by condensed high explosives is reviewed. Carbon resistors have been shown to provide a relatively inexpensive and direct method for such measurements, provided adequate calibration data are available. The gauge is fabricated by heat-sealing the carbon resistor (470 Ω, 0.125 W) into a suitable plastic material such as polystyrene; when subjected to a strong shock wave, the gauge undergoes compression and the conductivity increases in proprtion to the magnitude of the pressure. The present investigation was concerned with the experimental derivation of calibration equations relating the pressure (in gigapascal) as a function of the conductivity change ΔG (in siemens). The point of inflaction occurring at approximately 2.36 GPa, corresponding to 0.02082 S, is in agreement with previous observations in the literature. Additional experiments are being planned to resolve a problem concerning oscillatory ringing in the gauge voltage records.
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  • 9
    ISSN: 0730-6679
    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
    Notes: Blending of immiscible polymers offers attractive opportunities for developing new materials with useful combinations of properties. However, simple blends often have poor mechanical properties and unstable morphologies. Compatibilization of such blends is necessary. Preformed graft or block copolymers have been traditionally added to act as compatibilizers. Another route, however, is to generate these copolymer compatibilizers in situ during melt blending using functionalized polymers. In this review, a variety of reactive polymers that have been utilized in the reactive compatibilization of polymer blends is examined. They are classified into six major categories according to the types of reactive groups they have, namely, maleic anhydride, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl and epoxide, and reactive groups capable of ionic bonding. Their preparation methods and applications and the chemical reactions they undergo during melt blending are presented. © 1992 John Wiley & Sons, Inc.
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