ORIGINAL CONTRIBUTION

Rheologica Acta

, Volume 39, Issue 6, pp 574-582

First online:

Equibiaxial extensional flow of polymer melts via lubricated squeezing flow. II. Flow modeling

  • David C. VenerusAffiliated withDepartment of Chemical and Environmental Engineering and Center of Excellence in Polymer Science and Engineering Illinois Institute of Technology Chicago, Illinois 60616, USA e-mail: venerus@iit.edu
  • , M. KompaniAffiliated withDepartment of Chemical and Environmental Engineering and Center of Excellence in Polymer Science and Engineering Illinois Institute of Technology Chicago, Illinois 60616, USA e-mail: venerus@iit.edu
  • , B. BernsteinAffiliated withDepartment of Chemical and Environmental Engineering and Center of Excellence in Polymer Science and Engineering Illinois Institute of Technology Chicago, Illinois 60616, USA e-mail: venerus@iit.edu

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Abstract

A model for lubricated squeezing flow of a viscoelastic fluid is developed in order to study the viability of this flow as a rheological technique for generating equibiaxial extensional deformations in polymer melts. In this simple flow model, the melt, described by an upper-convected Maxwell fluid, is squeezed between thin films of a Newtonian fluid. Comparisons of the model predictions for constant strain rate and constant stress flows are made with experimental results presented in the first paper. Predictions from the model are able to describe the effects of lubricant viscosity and experimental configuration and indicate the technique fails for these flows at Hencky strains of approximately one. The cause for this failure is lubricant thinning, which leads to significant errors in both the measured stress difference and the strain.