Equibiaxial elongation of entangled polyisobutylene melts: Experiments and theoretical predictions

Document Type

Article

Publication Date

5-1-2024

Abstract

Equibiaxial elongational deformations are omnipresent in polymer processing technologies. The challenge of generating well-controlled equibiaxial elongational deformations in the laboratory has, however, severely inhibited progress on understanding the rheology of polymeric liquids and other complex fluids in this flow. More recently, a novel technique known as continuous lubricated squeezing flow has been developed that allows for rheological measurements in equibiaxial elongational deformations. In the present study, we examine the rheological behavior of two entangled polyisobutylene (PIB) melts with different molecular weight distributions in constant strain rate equibiaxial elongation flows. These new data are compared with predictions from two molecular models for entangled polymer melts inspired by the idea that entanglements dominate the relaxation dynamics. One model is the discrete slip-link model (DSM), and the other is known as the Rolie Double Poly (RDP) model. For the PIB with a relatively narrow molecular weight distribution, the predictions of both models are in good agreement with experiments and the DSM gives nearly quantitative agreement. For the broad molecular weight distribution PIB, both the DSM and RDP model predict strain hardening, which is not observed in the experiments.

Identifier

85189493811 (Scopus)

Publication Title

Journal of Rheology

External Full Text Location

https://doi.org/10.1122/8.0000809

e-ISSN

15208516

ISSN

01486055

First Page

341

Last Page

353

Issue

3

Volume

68

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