Dynamic Viscoelasticity, Stress Relaxation and Elongational Flow Behavior of High Density Polyethylene Melts
1990; Society of Rheology, Japan; Volume: 18; Issue: 2 Linguagem: Inglês
10.1678/rheology1973.18.2_80
ISSN2186-4586
AutoresKatsuyuki Yoshikawa, Nobuhiro Toneaki, Yoshihiro Moteki, Masaoki Takahashi, Toshiro Masuda,
Tópico(s)Polymer crystallization and properties
ResumoShear and elongational flow properties of high density polyethylene melts are studied. Effects of long branching and molecular weight distribution on rheological properties are investigated for two types of samples, which are produced using different kind of catalysts.The following conclusions are obtained. (1) Contribution of a relaxation mechanism with very long relaxation times due to the long branch of the sample appears in dynamic viscoelastic functions, relaxation modulus and in elongational viscosity. (2) Difference in shear flow properties between two types of samples is marked in the region corresponding to much lower stress level than that met in the measurement of melt flow rate. (3) The strain dependence of damping function obtained in stress relaxation measurement is similar to each other for two types of samples. (4) Sharp upturn of elongational viscosity is observed for two samples; one with long branch (es) and other with (possibly) extremely high molecular weight tail.
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