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  • Polymer and Materials Science  (9)
  • INSTRUMENTATION AND PHOTOGRAPHY  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Study of degradation of polystyrene by means of mass spectrometryPresented at the International Congress of Pure and Applied Chemistry, New York, September, 1951. (1952)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 8 (1952), S. 555-571 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The degradation of polystyrene by heat and ultraviolet radiant energy was followed by mass spectrometric analysis of the gaseous products evolved. Oxygen content, discoloration, and insolubility of the treated polymer were also investigated. The degradation of polystyrene involves two different processes: (1) the breakdown of thermolabile groups formed in the polymer prior to degradative treatment; this breakdown is caused by exposure to heat at 120°C. in vacuo and 115°C. in oxygen and to ultraviolet radiant energy at 120°C. in vacuo and 118°C. in oxygen; it is accompanied by the removal of residual materials such as solvent; and (2) the oxidation of the polymer caused by exposure to ultraviolet radiant energy in the presence of oxygen. The evolution of benzene, methyl ethyl ketone, dimethylbenzenes, and alcohols is associated with the first stage involving the breakdown of thermolabile groups and the removal of residual materials. Compounds such as formaldehyde, formic acid, and acetic acid are produced as a result of oxidation of the polymer. The oxygen content of the polymer was decreased from 0.33 to approximately 0.1 percent by heating at 120°C. in vacuo and at 115°C. in oxygen, and by exposure to ultraviolet radiant energy at 120°C. in vacuo. Ultraviolet treatment at 118°C. in oxygen for 250 hours quadrupled the original oxygen concentration. Discoloration of the polystyrene was definitely noted only on exposure to ultraviolet radiant energy in oxygen and is associated with oxidation of the polymer. The material became insoluble as a result of all heat and ultraviolet treatments. The amount of insoluble material increased with severity of exposure conditions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1952.120080513
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  • 2
    Electronic Resource
    Electronic Resource
    Depolymerization as a chain reaction (1950)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 5 (1950), S. 615-632 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1950.120050509
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  • 3
    Electronic Resource
    Electronic Resource
    Pyrolysis of α- and β-deuterostyrene polymers (1955)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 15 (1955), S. 157-166 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Recently the depolymerization of addition polymers has been treated in terms of four elementary reactions: initiation, propagation, transfer, and termination; analogous to those reactions which operate in the polymerization process. It is the transfer process which, according to its relative importance, gives rise to differences in polymers in the monomer yield, in the rate vs. conversion behavior, and in the molecular weight vs. conversion behavior. The transfer process is assumed to operate through the abstraction of a hydrogen from the polymer chain by a radical. By substituting a deuterium for the hydrogen at selected points in the polymer chain, the amount of the transfer process should be decreased due to an isotope effect. Two deuterated polymers were made from α- and β-deuterated styrenes and their depolymerization behavior studied. In the case of the α-deuterostyrene polymer the results are compatible with a ½ decrease in the rate of the transfer process and also an increase in the rate of the propagation. The results with the β-polymer imply an increase in both the transfer and propagation rates. The data obtained indicate that in polystyrene the intermolecular transfer process is mainly responsible for the fall in molecular weight of the polymer residue during depolymerization.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1955.120157913
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  • 4
    Electronic Resource
    Electronic Resource
    Some aspects of depolymerization kinetics (1951)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 6 (1951), S. 39-44 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A brief discussion of the importance of the transfer step and its effect in the pyrolysis of polyethylene is given. In this case the removal, by molecular distillation, of smaller species from the reacting mixture modifies the kinetics. The molecular weight decreases less rapidly and tends to a limiting value depending on the maximum size of the evaporating molecules. The number distribution of the latter is, in a first approximation, independent of their size. The pertinent expressions are presented and the general solution of the rate equations which can be used to obtain higher approximations is given.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1951.120060107
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  • 5
    Electronic Resource
    Electronic Resource
    Degrading mixtures of monodisperse poly-α-methylstyrenes: Rates and anomalous molecular weight distributions (1975)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 13 (1975), S. 1783-1787 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: When a mixture of two monodisperse samples of poly-α-methylstyrene is thermally degraded, the components behave independently, as a first approximation, as shown by GPC and rate of volatilization data. The ratio Mw/Mn, before approaching the ultimate value of 2.0, first goes through a minimum at a much lower value.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1975.180130910
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  • 6
    Electronic Resource
    Electronic Resource
    Radiation-induced polymerization of hexafluoropropylene at high temperature and pressure (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 2229-2240 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The radiation-induced polymerization of hexafluoropropylene was studied in the pressure and temperature ranges of 4,500-15,000 atm. and 100-230°C., respectively. Retardation was a serious problem; data thought to apply to the unretarded polymerization are summarized below. At 1,500 rad/hr. the polymerization rate was 15%/hr. at 230°C. and 15,000 atm. The activation enthalpy and volume are 9.5 kcal./mole and -10 cc./mole, respectively. The rate varies as the square root of the radiation intensity. The largest intrinsic viscosity of the polymer is 2.0 dl./g.; values increase with temperature and pressure. At 130°C. and 10,000 atm. the intrinsic viscosity was the same at two radiation intensities.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.150040917
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  • 7
    Electronic Resource
    Electronic Resource
    Electron spin resonance spectra of aged, γ-irradiated polystyrenesPaper presented before the 140th National Meeting of the American Chemical Society, Chicago, September 4, 1961. (1963)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 1 (1963), S. 1521-1529 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electron spin resonance spectrum of polystyrene that has been γ-irradiated at -196°C. changes gradually with time from a broad three-peaked structure with outer derivative peaks at ±46 gauss to a much narrower structure with poorly separated outer derivative peaks at ±21-24 gauss. The deuterated polystyrenes behave likewise in general. The aged radicals of α,β,β-trideuterostyrene and β,β-dideuterostyrene exhibit only a single peak with derivative maxima at ±7 or 8 gauss from center. The aged spectra are all consistent with the hypothesis of major hyperfine interaction with β hydrogens. During the aging about 80% of the original radicals are lost, but the remainder are very long-lived. Poorly evacuated samples or those with added benzene decay much more rapidly.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1963.100010506
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  • 8
    Electronic Resource
    Electronic Resource
    Stress relaxation of γ-irradiated fluorocarbon elastomersPresented before the 144th National American Chemical Society Meeting, Los Angeles, California, April 1963. Based on work sponsored by the National Aeronautics and Space Administration. (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 1685-1712 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinylidene fluoride), polytrifluoroethylene, and two rubbery copolymers with vinylidene fluoride were crosslinked by γ-irradiation in vacuum. Radiation-induced chain scissions in the copolymers were studied by observing the relaxation of stress at constant extension during further irradiation at 27°C., at 0.31-2.7 Mr./hr. in nitrogen and in air. From gel content, swelling, and elasticity, the values of Gc (crosslinking) and Gd (scission) were respectively; for CF2CFH, Gc = 2.2 and Gd = 0.4; for CF2CH2, 2.0 and 0.3; for CF2CH2 + C3F6, 3.4 and 1.3; for CF2CH2 + CF2CFCl, 1.8 and 1.4. The Gd values from stress relaxation were variable; the lowest were: for CF2CH2 + C3F6, 4.6 in nitrogen and 8.4 in air; for CF2CH2 + CF2CFCl, 1.9 in nitrogen and 3.6 in air.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100030503
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  • 9
    Electronic Resource
    Electronic Resource
    Pyrolysis of vinyl and vinylidene fluoride polymers: Influence of prior γ-irradiation (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 4 (1966), S. 349-365 
    Details
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantitative comparisons were made between the rates of thermal volatilization of several fluoropolymers before and after exposure to γ-radiation. The effects of γ-irradiation on poly(vinyl fluoride) and poly(vinylidene fluoride) were also investigated by swelling and sol-gel ratios. With both polymers as well as with polytrifluoroethylene, crosslinks occur predominantly, though there is an appreciable number of scissions. The rates of volatilization and char formation were enhanced by γ-radiation, whereas the previously studied polytrifluoroethylene did not produce more char upon irradiation, although radiation did accelerate its volatilization. It is believed that in polytrifluoroethylene the enhanced rates of volatilization occur by a different mechanism than in the case of the vinyl and vinylidene fluoride polymers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.150040208
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  • 10
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    Unknown
    Thermogravimetric instrument (1963)
    In:  CASI
    Details
    Publication Date: 2019-05-29
    Description: Thermogravimetric instrument to measure volatility under both isothermal and nonisothermal conditions and to study thermal decomposition
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
    Type: NASA-CR-74783
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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