Anisotropic thermal diffusivity measurements in deforming polymers and the stress-thermal rule

D. C. Venerus, J. D. Schieber, H. Iddir, J. Guzmán, A. Broerman

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

In recent years, both experimental and theoretical research on energy transport in deforming polymeric materials has increased. Theoretical results indicate that the thermal conductivity in such systems is anisotropic, and support, analogous to the well-known stress-optic rule, the validity of a stress-thermal rule where the thermal conductivity and stress tensors are linearly related. In this study a method to measure the thermal diffusivity in deforming polymers has been developed. The method is based on an optical technique known as forced Rayleigh scattering. This sensitive and non invasive technique is shown to be capable of quantitative measurements of anisotropic thermal diffusivity in both static and dynamic (relaxing) polymers subjected to deformations. Results have been obtained for a polymer melt in step-shear strain flows and a cross-linked elastomer in uniaxial extension. Thermal diffusivity data are complemented by measurements of stress and birefringence so that evaluations of the stress-optic and stress-thermal rules can be made. Results show that the thermal diffusivity is enhanced in the flow (or stretch) direction compared to the equilibrium value and that the stress-thermal rule is valid for the modest deformations achieved in this study.

Original languageEnglish (US)
Pages (from-to)1215-1225
Number of pages11
JournalInternational Journal of Thermophysics
Volume22
Issue number4
DOIs
StatePublished - Jul 1 2001
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Keywords

  • Anisotropic thermal diffusivity
  • Deforming polymers
  • Forced Rayleigh scattering
  • Stress-thermal rule

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