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Polymers Under Pressure

  • W. Pechhold
Chapter
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Part of the NATO ASI Series book series (NSSB, volume 286)

Abstract

Using the bulk Grüneisen Parameter, an equation of state V(p,T) is derived from thermodynamics. It can be successfully applied to crystalline as well as glassy polymers and in a first approximation also to polymer melts. This is shown for high pressure crystallized Polyethylene and — in a contribution by Dollhopf — for Polycarbonate and Polystyrene.

Next, the pressure dependence of the glass relaxation process (in PVAc), as measured by dielectric spectroscopy, is discussed and analysed using the dislocation concept in the meander model and an appropriate Grüneisen parameter γdisl. The latter turns out to be about half the value of the bulk parameter, which might be checked by measuring the pressure dependence of the shear modulus G(p).

Finally, the pressure dependence of phase transitions and its transition data will be described for several examples, including the high temperature transition of PE into a CONDIS-phase and the subsequent melting, as well as the nematic/isotropic transition of LC-polymers and — in a contribution by Schwarzenberger — the lamellar/isotropic transition of PDES.

Keywords

Pressure Dependence Activation Diagram Orientational Order Dislocation Wall Mesogenic Group 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1991

Authors and Affiliations

  • W. Pechhold
    • 1
  1. 1.Abteilung Angewandte PhysikUniversität UlmUlmGermany

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