Evaluate the nonlinear viscoelasticity of polyolefin melts using the Larson model. Issue 10 (24th October 2013)

• Record Type: Journal Article
• Authors: Lin, Gwo‐Geng; Song, Yi‐Hu; Shiu, Tai‐Yi; Cheng, Hsin‐Der
• Is Part Of: Polymer engineering & science. Volume 54:Issue 10(2014:Oct.)
• Page Start: 2354
• Page End: 2361
• Publication Date: 2013-10-24
• Subjects: Polymer engineering -- Periodicals; Polymers -- Periodicals; 668.9
• DOI: 10.1002/pen.23788
• Languages: English
• ISSNs: 0032-3888

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Nonlinear rheological properties of polyolefins have long been studied and predicted by using the Larson model with the damping function generally obtained from the stress relaxation measurements. In this study, we investigate the nonlinear rheological properties of high density polyethylene (HDPE) and polypropylene (PP) using the Larson model with damping functions obtained from either the dynamic frequency sweep or the stress relaxation test. Experimental measurements and their corresponding model predictions for the rheological parameters were then compared to evaluate the applicability of the Larson model to the nonlinear rheology, and the following conclusions could be achieved. The steady shear viscosity could be satisfactorily described by the Larson model with the damping functions obtained from the two different methods, except at shear rates higher than 10³ s⁻¹. The predicted first normal stresses also account for the measured data, except for those using the stress relaxation data showing a little deviation for the PP sample. In addition, the predictions for elongation viscosity are also in good agreement with the experimental results within the short range of elongation rate achieved in this work. POLYM. ENG. SCI., 54:2354–2361, 2014. © 2013 Society of Plastics Engineers</p> </abstract>