Measurements and modeling of temperature-strain rate dependent uniaxial and planar extensional viscosities for branched LDPE polymer melt

POLYMER

卷:104

Article

Zatloukal, Martin¹ 

[1] Tomas Bata Univ Zlin, Fac Technol, Ctr Polymer, Vavreckova 275, Zlin 76272, Czech Republic

关键词: Orifice die;    Planar extensional viscosity;    Uniaxial extensional viscosity;    Cogswell model;    Entrance pressure drop;    Polymer melts;    Capillary rheometer;    Constitutive equations;   

DOI  :  10.1016/j.polymer.2016.04.053

来源: Elsevier

【 摘 要 】

In this work, novel rectangle and circular orifice (zero-length) dies have been utilized for temperature-strain rate dependent planar and uniaxial extensional viscosity measurements for the LDPE polymer melt by using standard twin bore capillary rheometer and Cogswell model and the capability of five different constitutive equations (novel generalized Newtonian model, original Yao model, extended Yao model, modified White-Metzner model, modified Leonov model) to describe the measured experimental data has been tested. It has been shown that chain branching causes the strain hardening occurrence in both uniaxial and planar extensional viscosities and its maximum is shifted to the higher strain rates if the temperature is increased. The level of uniaxial extensional strain hardening for the branched LDPE sample has been found to be higher in comparison with the planar extensional viscosity within wide range of temperatures. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

Free