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
    A positron annihilation lifetime study of isothermal structural relaxation in bisphenol-A polycarbonate (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 26 (1988), S. 1541-1552 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positron annihilation lifetime spectroscopy has been used to study the isothermal relaxation response of compression molded bisphenol-A polycarbonate at temperatures of 263, 273, and 303 K. The temperature dependence of both the lifetime and intensity of the ortho-Positronium (o-Ps) pickoff component is discussed in terms of ductile-to-brittle transition behavior and free volume theory. An additive exponential model and the Williams-Watt model were used to analyze the relaxation as a function of temperature and provided results consistent with the anticipated molecular mobility of polycarbonate at sub-Tg temperatures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1988.080260605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    On the analysis of positron annihilation lifetime spectroscopy data in semicrystalline miscible polymer blend systems (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 52 (1994), S. 1191-1202 
    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 free volume probing technique, positron annihilation lifetime spectroscopy (PALS) is used to characterize miscible blends of amorphous polycarbonate with a semicrystalline copolyester at room temperature. The paper describes the analysis required to use the PALS technique to probe the amorphous regions in which the miscibility of the blends occurs. Analysis of the raw PALS data in this system involves taking account of the influence of crystallinity on the PALS results. The results demonstrate that the PALS technique is able to discriminate between free volume in the amorphous regions of as-molded and annealed samples. This difference in free volume between samples of differing thermal history is assigned to the influence of polymer crystals on the stress state of the miscible amorphous regions. © 1994 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1994.070520903
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Rapid analysis of a peptide by fast-atom bombardment mass spectrometry after polyacrylamide gel electrophoresis (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 346-347 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Gel electrophoresis has been a powerful technique for the separation of peptides and proteins for many years. After electrophoresis separation on a polyacrylamide gel, the peptide bradykinin was localized using Coomassie Blue as a staining dye. Excess dye was removed by washing the gel with water, For mass spectrometric analysis, bands containing the peptide were crushed, extracted with acetic acid and the eluent applied to the fast-atom bombardment probe. Under these conditions the protonated molecule of bradykinin was clearly observed. Also apparent were sequence ions at about the same intensity observed from authentic bradykinin.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290031008
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The effect of crystallinity on chain mobility and free volume in the amorphous regions of a miscible polycarbonate/polyester blend (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 1237-1247 
    Details
    ISSN: 0887-6266
    Keywords: Polycarbonate ; ThermX ; semicrystalline polyester ; positron lifetimes ; miscible blends ; free volume ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Homopolymers and blends of polycarbonate/ThermX have been investigated by differential scanning calorimetry, dynamic mechanical analysis, density measurements, and positron annihilation lifetime spectroscopy. The study focuses on the chain mobility and free volume in the amorphous miscible regions of the blends and how this mobility and free volume are affected by increasing crystallinity. It is proposed that judicious annealing, which results in increasing crystallinity (while avoiding ageing or transesterification), induces a constraint on the amorphous region leading to an increase in Tg and coalescence of free volume sites. © 1994 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1994.090320711
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The effects of physical aging in polycarbonate (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 387-405 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effects of physical aging below the glass transition temperature on selected properties of polycarbonate have been studied. Changes in tensile yield strength, post yield stress drop, and fracture toughness as a result of annealing at 120°C for 240 h have been measured and are related to changes in free volume as measured by positron annihilation lifetime spectroscopy. The free volume concentration remains constant during the aging heat treatment at 120°C but decreases after cooling due to aging. The relationship between free volume changes and physical property changes is discussed in terms of molecular conformations and fracture mode. The effect of aging on fracture morphology is presented to aid interpretations of fracture mode.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090280310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Compatibilized linear low-density polyethylene/isotactic polypropylene blends studied by positron annihilation lifetime spectroscopy (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 28-33 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Positron annihilation lifetime spectroscopy (PALS), capable of probing free volume, is used to study the effect of compatibilizer concentration, compatibilizer type, and the effect of blend processing on the morphology and properties of an immiscible linear low-density polyethylene/polypropylene system. It is proposed that improvement of fracture toughness due to compatibilization can be attributed to the packing (and bonding) at interfaces. Improved interfacial packing and bonding result in lower free volume concentration than expected from component additivity, with a concomitant increase in plastic deformation on impact.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Isothermal volume relaxation in aged polycarbonate measured by positron annihilation lifetime spectroscopy (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 762-768 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 positron annihilation lifetime spectroscopy (PALS) technique is used to measure volume relaxation in physically aged glassy polycarbonate. The relaxation times and activation energy calculated for the isothermal relaxations in the aged polycarbonate are greater than those parameters calculated for unaged polycarbonate. The activation energy of 8.2 kcal/mol in the aged polycarbonate is used to identify the phenyl group motion or the cooperative carbonate-phenyl interaction as the molecular features responsible for the thermally induced open volume relaxations. It is postulated that the open volume relaxation kinetics as measured by PALS can be used as a nondestructive indication of property differences between aged and unaged polycarbonate.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760301303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...