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
    Quantitative analysis of PMR-15 polyimide resin by HPLC (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 2893-2913 
    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: PMR-15 resin solutions consist of nadic ester (NE), the dimethyl ester of 3,3′,4,4′-benzopheno-netetracarboxylic acid (BTDE), and 4,4′-methylenedianiline (MDA) dissolved in methanol in a 2.000/2.087/3.087 molar ratio. Other chemical species may be present as a result of impurities in the monomers or reaction products which form upon aging of the solution. The effect of these other chemical species on the resin cure chemistry and composite properties is only partially understood. The composition of 50 wt % PMR-15 resin solutions was measured by reverse phase, high performance liquid chromatography (HPLC). The major impurity in the monomers was found to be monoester and tetraacid impurities in the BTDE solution. These impurities could be eliminated by recrystallizing the dianhydride from which the BTDE was made. Triester formation was not a problem because of the high rate of esterification of the anhydride compared to that of the carboxylic acid. When the PMR-15 monomer solution was aged at room temperature, the concentration of BTDE remained constant. The concentration of NE and MDA decreased as their reaction products formed. The amide-acid formed quickly but remained at a small concentration. The monoimide and bisimide concentrations increased monotonically during the entire aging time. When the PMR-15 resin was stored as a dried film, imidization of NE and MDA still occurred, but at a reduced rate.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330823
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of imidization and crosslinking in PMR polyimide resin (1979)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 17 (1979), S. 2529-2539 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Infrared spectroscopy and differential scanning calorimetry were used to study the imidization and crosslinking kinetics of norbornenyl-capped addition type of polyimide resins (designated PMR for polymerization of monomer reactants). The spectral and thermal analyses were performed on resin specimens that had been isothermally aged at temperatures appropriate for imidization (120-204°C) and crosslinking (275-325°C). Imidization occurs rapidly (about 10-2 min-1) at short times, but, at times longer than about 0.5 hr, the rate decreases significantly (about 10-4 min-1). The crosslinking reaction exhibits first-order kinetics during the initial part of the reaction, and its rate appears to be limited by the reversion of the norbornenyl Diels-Alder adduct. Both the first-order dependence and the activation energy (about 44 kcal) are consistent with this interpretation. The total heat evolved per mole of end cap during crosslinking shows an inverse dependence on the molecular weight of the imido prepolymers. This reflects the effect of end-cap dilution and decreased mobility of the larger oligomers.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1979.170170825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Quantitative analysis of PMR-15 polyimide resin by HPLC (1987)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The concentration of individual components and of total solids of 50 wt pct PMR-15 resin solutions was determined using reverse-phase HPLC to within + or - 8 percent accuracy. Acid impurities, the major source of impurities in 3,3', 4,4'-benzophenonetetracarboxylic acid (BTDE), were eliminated by recrystallizing the BTDE prior to esterification. Triester formation was not a problem because of the high rate of esterification of the anhydride relative to that of the carboxylic acid. Aging of PMR-15 resin solutions resulted in gradual formation of the mononadimide and bisnadimide of 4,4'-methylenedianiline, with the BTDE concentration remaining constant. Similar chemical reactions occurred at a reduced rate in dried films of PMR-15 resin.
    Keywords: CHEMISTRY AND MATERIALS (GENERAL)
    Type: Journal of Applied Polymer Science (ISSN 0021-8995); 33; 2893-291
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unknown
    Microgravity Combustion Science and Fluid Physics Experiments and Facilities for the ISS (2001)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: At the NASA Glenn Research Center, the Microgravity Science Program supports both ground-based and flight experiment research in the disciplines of Combustion Science and Fluid Physics. Combustion Science research includes the areas of gas jet diffusion flames, laminar flames, burning of droplets and misting fuels, solids and materials flammability, fire and fire suppressants, turbulent combustion, reaction kinetics, materials synthesis, and other combustion systems. The Fluid Physics discipline includes the areas of complex fluids (colloids, gels, foams, magneto-rheological fluids, non-Newtonian fluids, suspensions, granular materials), dynamics and instabilities (bubble and drop dynamics, magneto/electrohydrodynamics, electrochemical transport, geophysical flows), interfacial phenomena (wetting, capillarity, contact line hydrodynamics), and multiphase flows and phase changes (boiling and condensation, heat transfer, flow instabilities). A specialized International Space Station (ISS) facility that provides sophisticated research capabilities for these disciplines is the Fluids and Combustion Facility (FCF). The FCF consists of the Combustion Integrated Rack (CIR), the Fluids Integrated Rack (FIR) and the Shared Accommodations Rack and is designed to accomplish a large number of science investigations over the life of the ISS. The modular, multiuser facility is designed to optimize the science return within the available resources of on-orbit power, uplink/downlink capacity, crew time, upmass/downmass, volume, etc. A suite of diagnostics capabilities, with emphasis on optical techniques, will be provided to complement the capabilities of the subsystem multiuser or principal investigator-specific experiment modules. The paper will discuss the systems concept, technical capabilities, functionality, and the initial science investigations in each discipline.
    Keywords: Space Sciences (General)
    Type: NASA/TM-2001-210202 , NAS 1.15:210202 , E-12322 , Spacebound 2000; May 15, 2000 - May 18, 2000; Vancouver, British Columbia; Canada
    Format: application/pdf
    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...