Assessment of nonlinear strain measures for extensional and shearing flows of polymer melts

✍ Scribed by M. H. Wagner; J. Schaeffer

• Publisher: Springer-Verlag
• Year: 1994
• Tongue: English
• Weight: 866 KB
• Volume: 33
• Category: Article
• ISSN: 0035-4511
• DOI: 10.1007/bf00366335

✦ Synopsis

From stress-strain experiments in extensional and shearing flows, nonlinear strain measures and effective damping functions are derived for a polyisobutylene melt. The strain measures determined in planar extensional flow and in simple shear flow coincide. Experimental results are compared with predictions of two molecular theories, the Doi-Edwards model and the molecular stress function approach of Wagner and Schaeffer. Discrepancies between theories and experiment lead to a reconsideration of the classification of extensional flows. The symmetry of the flow field is identified and quantified as an important parameter influencing the strain measure, and a unifying strain measure for general extensional and shearing flows of polymer melts is presented.