ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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
    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 faint emission of light by various classes and types of polymers when heated in the presence of oxygen, oxyluminescence, was studied by means of a photomultiplier tube and sensitive microammeter. Among the polymers with a carbon-carbon backbone, the polymers having the greater number of tertiary carbon atoms generally showed greater intensities of luminosity. Polystyrene was a notable exception to this generalization. The shape of the luminosity versus time curves varied with the type of polymer. It was also found that the emission of light did not stop instantly when the oxygen atmosphere was replaced by an inert gas, but rather followed an exponential type of decay. The rate of decay appeared to be different with different types of polymers. The intensities of luminescence and the times required to reach maximum or steady state luminescence were compared with oxygen uptake data for various polymers. In general there was a qualitative, but not necessarily quantitative correlation between the luminous intensities and polymer stabilities in the presence of oxygen.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 4 (1962), S. 129-138 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 7 (1961), S. 620-624 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The surface temperature during nucleate boiling was measured with a special thermocouple so designed as to measure the temperature of a small area and to have an extremely rapid response time. The surface temperature was found to drop occasionally 20° to 30°F. in about 2 msec. during the boiling of water. This indicates a rapid extraction of heat during a short time interval. The significance of this observation is that it provides an important new clue to an understanding of nucleate boiling. A hypothesis is advanced to explain these observations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 10 (1964), S. 656-660 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: By using a special surface thermocouple Moore and Mesler have measured large temperature fluctuations during nucleate boiling of water on chromel P surface. They found that the temperature dropped 20° to 30°F. in about 2 msec. but required 10 to 20 msec. to recover. They have postulated that the surface was cooled during initial bubble growth by evaporation of a microlayer into the bubble. To test this hypothesis a technique was developed to photograph a bubble growing from an artificial site as the surface temperature was measured.Temperature fluctuations were recorded on an oscilloscope which automatically triggered the bubble photographs by means of a time delay unit and flash tube. Photographs of bubbles were taken at 1 μsec. exposure time and ranged from about 10 μsec. after the start of the temperature drop to about 1 msec. before the start of another cycle. The photographs show that the surface cools during bubble growth and recovers during bubble departure.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 4 (1960), S. 219-224 
    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: Attention is called to the variables effecting the extraction of polypropylene. Under controlled conditions, the extraction of polypropylene with first diethyl ether and then n-heptane will give reproducible results. It is necessary to extract with heptane in an atmosphere of nitrogen. The values obtained by the extraction procedure described are regarded as relative measures of the amounts of isotactic, stereoblock and atactic material present in a sample. Extraction with n-heptane alone by this procedure also gives the same value of relative isotacticity. Infrared studies showed that the ether soluble fractions were essentially atactic, while the n-heptane-soluble or stereoblock material possessed a degree of order corresponding to 20-40% isotactic polypropylene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 7 (1963), S. 959-969 
    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 initial stages of isotactic polypropylene oxidation were investigated by oxidizing at 130°C. to various extents up to 10 ml. of oxygen consumed per gram of polymer. The development of infrared absorption bands in the carbonyl regions was followed, as increasing amounts of oxidation occurred. The oxidation uptake curves showed that both autocatalytic rate and induction time depended primarily on the thickness of the sample, contrary to the case of polyethylene. This indicated the initiation process was primarily diffusion controlled for samples of the thickness range studied. The presence of copper shortened the induction times and increased the autocatalytic rate. In this case, the dependency of the induction time on thickness was less. Dielectric data showed that polypropylene became unsuitable electrically at about the point where the autocatalytic oxidation set in. It was also found that the effects of prior exposure to oxidative conditions were cumulative to a considerable extent, and thus resulted in shorter induction times.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 8 (1964), S. 997-1006 
    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 oxyluminescence of polypropylene and polyethylene stabilized with various amounts of 4,4′-thiobis(3-methyl-6-tert-butylphenol) were studied and compared with oxygen uptake data. It was found that there was a correlation, although not linear, between the two methods. In the case of the stabilized polypropylenes, a pronounced aging effect was noticed. The oxyluminescent behavior of stabilized polyethylene was somewhat different from that of stabilized polypropylene. The temperature coefficients of the oxyluminescence of polypropylene, polyethylene, nylon 6, polystyrene, polyurethane and polymethyl methacrylate were obtained. From these data the apparent activation energies for the light-emitting reaction were calculated. For the olefin polymers, these values are close to the activation energies of the oxidative degradation reaction obtained by other means. Both polyethylene and polymethyl methacrylate have different activation energies below their transition points as compared to higher temperature, indicating a different mode of reaction in the solid state from that occurring in the melt. An interesting transition luminescence, which was more pronounced in the absence of oxygen, was observed in the case of polyethylene.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 57 (1962), S. 641-650 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of a variety of phenols on the rate and degree of polymerization of styrene has been studied. With 1-naphthol it is found that polystyryl radicals abstract the phenolic hydrogen atom, since 1-naphthol has a far greater effect on the rate and degree of polymerization than 1-deuteroxynaphthalene. Many phenols do not significantly retard the polymerization of styrene and transfer constants ranging up to 7.7 × 10-3 have been estimated for them. Other phenols, such as 1-naphthol, 4-methoxyphenol and 2,6-diisopropylphenol, significantly decrease the rate and degree of polymerization. Transfer constants for these retarders have been calculated, both from the rate data alone by means of the treatment of Jenkins and from molecular weight data. The estimated values depend on the assumptions made concerning the mode of disappearance of the retarder radicals produced in the transfer reaction. Most of the retarders investigated give transfer constants in the range 10-2 to 10-1 but catechol, tert-butylcatechol, and pyrogallol give larger values. An increased rate of polymerization observed in mixtures of styrene and some phenols is probably due to a higher rate of production of radicals by the initiator, azobisisobutyronitrile.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 56 (1962), S. 267-272 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Titanium tetrafluoride has been successfully employed in combination with triisobutyl aluminum (TBA) as a Ziegler type of catalyst to polymerize butadiene. The resulting polymer has a higher cis to trans ratio and a higher degree of crosslinking than one prepared with the titanium tetrachloride-TBA catalyst. It is of interest that vinyl chloride, a monomer containing a donor atom, was polymerized with the TiF4-TBA catalyst. Titanium tetrafluoride is not a very effective catalyst for the Friedel-Crafts type of reactions.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 47 (1960), S. 259-265 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Anhydrous lithium perchlorate is an effective catalyst for the polymerization of certain vinyl monomers. Evidence shows that it behaves more as a cationic catalyst than a radical type, but is much milder in action than the better known representatives of this type of catalyst. Other perchlorates and lithium compounds show only a fraction or none of the activity of anhydrous lithium perchlorate in initiating vinyl polymerization.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...