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
    Influence of physical ageing on the α dielectric relaxation of poly(methyl acrylaie) (1985)
    Springer
    Polymer bulletin 14 (1985), S. 45-52 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this work are examined changes of the α relaxation spectrum of PMA during the structural relaxation process which follows a quenching from a temperature To above Tg to another T1 below Tg, which is mantained constant. It is found that the relaxation times spectrum is shifted towards longer times as the ageing time increases. At the same time, its form becomes more and more wide, approaching the form of the relaxation times spectrum calculated at temperatures above Tg from alternative dielectric measurements. A parameter measuring the shift of the spectrum, a(ta), is defined and its dependence on ageing time and annealig temperature is studied. The effective relaxation time of the structural relaxation process is calculated from a(ta) and it is found dependent on the temperature of annealing as well as on the value of a(ta)itself.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254914
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Dynamic mechanical and dielectric relaxations in poly(monoethylphenyl itaconate) (1997)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 35 (1997), S. 2749-2756 
    Details
    ISSN: 0887-6266
    Keywords: poly(monoethylphenyl itaconate) ; mechanical relaxation ; dielectric absorption ; dielectric loss modulus ; deconvolution method ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dynamic mechanical and dielectric relaxational behavior of poly(monoethylphenyl itaconate) at different frequencies and temperatures was studied. Three relaxation zones are found. The dynamic mechanical response is dominated by a relaxation peak at room temperature, labeled β relaxation. Two prominent shoulders labelled as γ and α relaxations are observed. Because of the overlapping of the α and γ with the β relaxation, a deconvolution method to improve the understanding of these phenomena is proposed. In spite of the complexity of the experimental spectra, the proposed deconvolution method seems to be a convenient approach to interpret the relaxational behavior of this polymer. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2749-2756, 1997
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    On the dynamic mechanical behavior of poly(methyl methacrylate) reinforced with Kevlar fibers (1991)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 12 (1991), S. 428-435 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The dynamic mechanical relaxation behavior of poly(methyl methacrylate) reinforced by continuous parallel Kevlar-49 fibers is investigated here on samples with several fiber volume fractions. The shifts in the temperature of the main relaxation of the matrix are interpreted according to free volume considerations and with the help of a thermomechanical block model. The dependence of the storage and loss moduli both on temperature and fiber content found experimentally can be reproduced by the model. It is not necessary to rely on the existence of an interphase to account for the modifications evidenced by the spectrum of the matrix, which can be explained on the basis of the two phase model.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750120608
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Dielectric relaxation study of low-density polyethylene by thermally stimulated depolarization currents and thermal sampling (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1645-1653 
    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 dielectric relaxation zone of a low-density polyethylene has been studied by thermally stimulated depolarization currents (TSDC) and thermal sampling (TS). Three relaxations have been found in this zone, which have been labeled γI, γII, and γIII in decreasing order of temperature. Samples of different crystallinities were subjected to several thermal treatments in order to study the molecular origin of each relaxation. The γI relaxation intensity changes with the thermal treatment, while the intensity of the γI relaxation is only slightly modified. Using TS it has been proved that the γI relaxation fulfils the compensation law with a high level of significance. Nevertheless, the experimental data are not enough to verity the γI and γIII relaxation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370617
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The β dielectric relaxation in some methacrylate polymers (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1297-1307 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Dielectric results at frequencies between 6 × 10-4 and 105 Hz are given for the β relaxation region of poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA), poly(butyl methacrylate) (PBMA), and poly(isobutyl methacrylate) (PisoBMA). Apparent activation energies and relaxation strengths are calculated, as well as the relaxation time distribution and the form factor of the Fuoss-Kirkwood equation. It is found that in PMMA, PEMA, and PBMA, the activation energy of the β relaxation is the same, the maxima occurring at the same frequency for the same temperatures, in accordance with the dynamic mechanical results of Heijboer, the dielectric results of Mikhailov, and at variance with data of Tetsutani et al. It is also found that the form factor follows the same temperature dependence. Data on the β relaxation of poly(hydroxyethyl methacrylate) (PHEMA), not previously reported, are also presented, and the displacement toward high temperatures of the β relaxation of PisoBMA and PHEMA is justified.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230702
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Application of the method of brather for the determination of complex dielectric permittivity from measurements of isothermal polarization current (1985)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 23 (1985), S. 1505-1511 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Some years ago, Brather proposed a method for calculation of the real and imaginary parts of the complex dielectric permittivity starting from measurements of isothermal polarization current. This method shows some advantages over the Hamon method, which is normally used. Both methods are applied in this work to the β relaxation of poly(butyl methacrylate). It is concluded that, with the usual accuracy of measurement, a combination of the two methods is advisable; Hamon's method is taken to be a first approximation to that of Brather. Results following the two procedures are compared, and their respective advantages and disadvantages are discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1985.180230804
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Effect of the cooling rate in the formation of glass on the α and β relaxations of some amorphous polymers (1984)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 24 (1984), S. 1202-1204 
    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: It has been observed in dynamic mechanical measures that the range of temperatures in which relaxation properties are affected by the diminishing of the free volume has, as a lower limit the temperature at which the maximum of G″ or tgδ, corresponding to the β relaxation, occurs. In dielectric measures on polymers in which the β relaxation is not predominant over the α relaxation, this temperature range is scarcely affected by changes in frequency, whereas the peak shifts according to its activation energy. This fact leads to the conclusion that the decrease in free volume due to a slow cooling from a temperature above Tg mainly affects mobility of the main chains under Tg, without disturbing the groups that give rise to the secondary relaxations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760241509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Anomalous dynamic mechanical behavior of poly(vinyl chloride) (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 596-596 
    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: In this paper, we present a study of the dynamic mechanicall behavior of a quenched poly(vinyl chloride). A new relaxation between the glass transition and the β transition is reported. We have related this new relaxation to an absence of physical aging.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760190812
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Dielectric relaxations in poly(thiocarbonates) (1994)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 32 (1994), S. 1617-1624 
    Details
    ISSN: 0887-6266
    Keywords: poly(thiocarbonates) ; dielectric relaxation ; conductivity ; physical aging ; molecular motions ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dielectric absorptions observed on six poly(thiocarbonates) (PTC) containing different substituents in the interphenylic carbon atom are subjected to a study. The α relaxation process associated with the glass transition temperature, which appears at the highest temperature studied, is overlapped with a strong conductive component. Between 80 and 100°C dielectric activity (β) is observed, which is related to structural relaxation phenomena. Polymers with double substitution on the interphenylic carbon atom show a γ relaxation with an activation energy of ca. 11 kcal mol-1 while those where the carbon atom is linked to a cyclohexyl group show higher activation energies and their respective characteristics. A cryogenic absorption around -120°C, for at least three polymers with an activation energy of about 5 kcal mol-1, is detected. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1994.090320904
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    facet.materialart.
    Unknown
    Variation of a.c. electrical properties of emeraldine base of polyaniline during its drying from suspension in m-cresol (1996)
    Elsevier
    Details
    Publication Date: 1996-05-01
    Print ISSN: 0379-6779
    Electronic ISSN: 1879-3290
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Elsevier
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...