Rheologica Acta

, Volume 45, Issue 1, pp 83–91

Simultaneous stress and birefringence measurements during uniaxial elongation of polystyrene melts with narrow molecular weight distribution

  • Clarisse Luap
  • Christian Müller
  • Thomas Schweizer
  • David C. Venerus
Original Contribution

DOI: 10.1007/s00397-005-0452-5

Cite this article as:
Luap, C., Müller, C., Schweizer, T. et al. Rheol Acta (2005) 45: 83. doi:10.1007/s00397-005-0452-5

Abstract

Tensile stress and flow-induced birefringence have been measured during uniaxial elongation at a constant strain rate of two polystyrene melts with narrow molecular weight distribution. For both melts, the stress- optical rule (SOR) is found to be fulfilled upto a critical stress of 2.7 MPa, independent of strain rate and temperature. Estimation of the Rouse times of the melts, from both the zero-shear viscosity and the dynamic-shear moduli at high frequency, shows that the violation of the SOR occurs when the strain rate multiplied by the Rouse time of the melt exceeds by approximately 3. The presented results indicate that in contrast to current predictions of molecular theories, the regime of extensional thinning observed by Bach et al. (2003) extends well beyond the onset of failure of the SOR, and therefore the onset of chain stretch in the non-Gaussian regime.

Keywords

Polymer meltBirefringenceElongational flowPolystyreneRheo-opticsNonlinear viscoelasticity

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Clarisse Luap
    • 1
  • Christian Müller
    • 1
  • Thomas Schweizer
    • 1
  • David C. Venerus
    • 1
    • 2
  1. 1.Department of MaterialsETH ZürichZürichSwitzerland
  2. 2.Department of Chemical and Environmental Engineering and Center of Excellence in Polymer Science and EngineeringIllinois Institute of TechnologyChicagoUSA