ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    The mechanical and magnetic alignment of liquid crystalline epoxy thermosets (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1845-1853 
    Details
    ISSN: 0887-624X
    Keywords: liquid crystalline ; networks ; epoxy ; thermotropic ; thermoset ; smectic ; nematic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The processing of a new series of liquid crystalline (LC) epoxy networks was evaluated. Above the glass transition temperature, the low crosslink density networks could be mechanically aligned. The mechanically oriented networks readily lost orientation upon heating. Highly anisotropic liquid crystalline (LC) epoxy networks were also prepared by aligning the mesophase of the prepolymer during the curing process under the influence of a magnetic field. Orientation parameters (f) of 0.13 to 0.57 were achieved by these processes as determined by x-ray diffraction analysis. The ability of the magnetically aligned networks to retain their orientation above the glass transition temperature was determined by time-resolved x-ray diffraction. The stability of the alignment of these networks was found to depend on crosslink density. The effect of the anisotropy of these networks was investigated by measuring the coefficient of thermal expansion (CTE). In the aligned networks, there was a substantial reduction in CTE parallel to the direction of the applied field compared to the randomly oriented networks. © 1992 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300907
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    NMR investigations of the possible cross reactions between cyanate and epoxy resins (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 32 (1994), S. 2203-2221 
    Details
    ISSN: 0887-624X
    Keywords: cyanate ; epoxy ; mixed resins ; curing ; cross reaction ; 13C-, 15N-, and 1H-NMR ; oxazolidinone ; carbamate ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The possible cross reactions indicated by solid-state NMR between cyanate functionalized resin and epoxy functionalized resin have been investigated by using both natural abundance and labeled monofunctional model compounds. These soluble products were isolated and purified by silica gel adsorption chromatography and gel permeation chromatography. They were fully characterized by high resolution 1H-, 13C-, 15N-NMR spectroscopy and by mass spectrometry. The major cross-reaction product is a racemic mixture of enantiomers, which contain an oxazolidinone ring formed by one cyanate molecule and two epoxy molecules. However, epoxy consumption lags cyanate consumption in the overall reaction as triazine formation from the cyanate is much faster than the two competing reactions, the cross reaction between cyanate and epoxy, and the self-polymerization of epoxy, under the conditions investigated. The cross reaction between cyanate and epoxy is limited. Approximately 12% of cross reaction between cyanate and epoxy was found in the overall reaction. In addition to the cross reactions of epoxy and cyanate, the reactions of epoxy and the carbamate, which is the major side product for the curing reaction of cyanate resin in solution, have also been investigated, and the mechanism of these reactions discussed. From the reactions of epoxy and carbamate, several products related to cross reaction between epoxy and cyanate have been isolated and identified. It is suggested that the reaction of epoxy and carbamate is one of the pathways in the overall cross reaction between epoxy and cranate resins. Finally, the mechanism of the overall cross-curing reaction between the diepoxy and dicyanate mixed resins is discussed. © 1994 John Wiley & Sons, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1994.080321201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Liquid crystalline epoxy thermosets based on dihydroxymethylstilbene: Synthesis and characterization (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1831-1843 
    Details
    ISSN: 0887-624X
    Keywords: liquid crystalline ; networks ; epoxy ; thermotropic ; thermoset ; smectic ; nematic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article describes the synthesis and characterization of a new series of liquid crystalline thermosets. Nematic epoxy-terminated oligoethers based on dihydroxy-α-methylstilbene were synthesized for this study. These prepolymers were crosslinked within the nematic mesophase using methylenedianiline. Depending upon the molecular weight and polydispersity of the oligoether, the crosslinking reaction resulted in networks with either a smectic or nematic molecular organization in contrast to the simple nematic phase of the oligoether. The formation of a smectic-like structure on curing was found to be related to the breadth of the prepolymer molecular weight. In those networks with a low crosslink density a clearing transition could be observed, whereas in the more highly crosslinked networks the molecular organization was frozen in until decomposition. The glass transition temperature of these LC networks rose as the crosslink density was increased, ranging from 35 to 152°C. In agreement with theory, the clearing transition of the networks was found to be dependent on the phase state during curing © 1992 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1992.080300906
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Influence of structure of hydroxyl-terminated maleopimaric acid ester on thermal stability of rigid polyurethane foams (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1803-1809 
    Details
    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: A series of hydroxyl-terminated maleopimaric acid esters (HTMAEs) and rigid polyurethane (PU) foams based on these HTMAEs were synthesized using chemically modified natural gum rosin and its derivative maleopimaric acid as raw materials. Thermal stability of these polyols and their corresponding rigid PU foams was studied by a thermogravimetric method and a dimensional stability measurement. It was shown that the thermal stability of the final foams was strongly dependent on the structure of their corresponding polyols. The thermogravimetric analysis curves of these rosin-based rigid PU foams displayed two distinct regions of weight loss. It has been shown that at the initial stage of weight loss the process was dominated by polyol component degradation; the second stage was governed by isocyanate component degradation. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070581019
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Influence of the composition of rosin-based rigid polyurethane foams on their thermal stability (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 59 (1996), S. 1167-1171 
    Details
    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: A series of rosin-based rigid polyurethane foams of different composition were synthesized directly from chemically modified gum rosin. The effect of the composition of these rosin-based rigid polyurethane foams on their thermal stability and compression strength was measured. It was shown that the onset temperature of weight loss and the dimensional stability at high temperature increased with increase of the molar ratio of NCO/OH. The TGA data further confirmed that the second stage weight loss in the two-stage weight loss process of these polyurethane foams was governed by thermal degradation of the isocyanate component. Although density had no significant influence on the TGA curves of the rosin-based rigid polyurethane foams, it had great influence on the dimensional stability at high temperature and compression strength of the foams. It has been shown that the inclusion of rosin in rigid polyurethane foams increases the strength and thermal stability compared with that of polyether-based ones. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 6
    Electronic Resource
    Electronic Resource
    Triazine networks modified with monofunctional reactive cyanate ester monomers (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 44 (1992), S. 1267-1274 
    Details
    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 preparation of cyanate ester thermosetting resins by coreacting a fluorinated bisphenol A dicyanate (6F-BADCY) monomer with a monofunctional reactive cyanate, namely, the dinonyl phenol cyanate (DNPC), is described in this paper. Our objective in this study was to modify the 6F-BADCY system with reactive diluents of a nonpolar nature and produce matrix resins processable at FR-4 epoxylike conditions. By introducing the monofunctional cyanate as a reactive diluent, it is expected that the molar crosslink density of the resulting network will be reduced. Highly branched triazine polymers will result from this approach. Dinonyl phenol cyanate was quantitatively synthesized by reacting dinonyl phenol with cyanogen bromide in the presence of triethylamine.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070440716
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Polyurethane-urea elastomers as working substances in rubber heat engines (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 2857-2872 
    Details
    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 possibility of using synthetic elastomers as working substances in a rubber heat engine was investigated at the laboratory and pilot scale. Two polyurethane-urea elastomers were subjected to expermental heat engine cycles at a variety of strains and temperature differences. It was found that optimum power and thermal efficiency were obtained at small strain perturbations where the elastomers were close to mechanical equilibrium. Crystallization of the rubbery phase during large strain perturbations is a nonequilibrium process which should be avoided. Quasi-ideal rubber behavior is approached in the pilot-scale heat engine which supports these conclusions.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070290916
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    ToF-SIMS and XPS studies of the interaction of silanes and matrix resins with glass surfaces (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 20 (1993), S. 457-467 
    Details
    ISSN: 0142-2421
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The interface between glass, glass fibres and epoxy resin in a composite has been studied using time-of-flight secondary ion mass spectrometry in static and scanning modes in combination with x-ray photoelectron spectroscopy. The presence of a multilayer of the polymeric hydrolysed γ-aminopropyltriethoxysilane (HAPS) on the glass surfaces has been confirmed. After extraction with hot water or toluene only a monomolecular interfacial layer of HAPS is chemically bound to the immediate glass surface through siloxane bonds, leaving the amino groups at the outer surface and available for reaction. It has been demonstrated that this interfacial layer plays an essential role in the coupling reaction between the amino group of the HAPS deposit and the epoxide group of the epoxy resins, diglycidyl ether of bisphenol A or S (DGEBA or DGEBS). These interfacial reactions were complicated by the presence of polydimethylsiloxane and the incorporation of substrate aluminium into the HAPS deposit. The aluminium sites appeared not to be involved in the coupling reaction.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/sia.740200520
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Research on the Crack Mechanism of High-Burning-Rate Propellant in the solid rocket motor (1995)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 20 (1995), S. 11-15 
    Details
    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: Through the analysis and calculation to the flow field in the solid rocket motor using high-burning-rate propellant, the authors believe that the existence of pressure difference between the inside and outside of the propellant tube causes the propellant crack. In this paper, the design method to eliminate the pressure difference is discussed. The theoretical results were certified by the experimental results.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19950200104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    facet.materialart.
    Unknown
    Gallium-bearing sphalerite in a metal-sulfide nodule of the Qingzhen (EH3) chondrite (1986)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The composition and possible history of the Qingshen (EH3) chondrite is presented. The chondrite contains a population of spheroidal metal-sulfide nodules, which display textural evidence of reheating and melting. Evidence of metal sulfuration is also present, suggesting replacement of metal by sulfide during melting. This process has led to the nucleation of perryite along metal-sulfide interfaces. The Ga-bearing sphalerite that was found may have formed by injection of molten sulfide droplets into the metal followed by subsolidus diffusion of Ga from the metal into the sulfide. The latter may occur because of Ga supersaturation in the metal during progressive sulfuration and its decreased affinity for the metal phase during cooling below the taenite-kamacite transition point.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Meteoritics (ISSN 0026-1114); 21; 23-31
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...