Rheological properties of bimodal polyethylenes produced with silica nanoparticle supported catalysts

Hao Liu (Corresponding author), Enrico M. Troisi, Johannes G.P. Goossens, John R. Severn, Cees W.M. Bastiaansen

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The rheological properties of bimodal ultra-high-molecular-weight polyethylenes (UHMWPEs) are investigated with an emphasis on the influence of the catalyst support. Bimodal UHMWPEs were produced in a single reactor with double support (DS) and single support (SS) catalyst systems. Dynamic measurements showed that the SS samples have a higher storage modulus at low frequencies than the DS samples with the same weight average molecular weight. After extrusion, the storage modulus of the bimodal DS samples increased to an identical value. The results indicate that the SS sample has a higher homogeneity than the DS sample. The steady-shear viscosities were measured to determine zero shear viscosities (η0) of the bimodal samples. The results show that the SS samples follow the relation η0 = KMw α with α = 3.19. However, the DS samples exhibit a substantial deviation from this relation especially in the intermediate Mw range around 1000 kg mol−1. The reason for the deviation is attributed to the heterogeneity in DS samples. The results demonstrate that the DS systems do not produce bimodal PEs with an intimate degree of mixing of short and long polymer chains even if silica nanoparticles are used as the support.

LanguageEnglish
Article number47577
Number of pages8
JournalJournal of Applied Polymer Science
Volume136
Issue number21
Early online date1 Jan 2019
DOIs
StatePublished - 5 Jun 2019

Fingerprint

Polyethylenes
Catalyst supports
Silicon Dioxide
Ultrahigh molecular weight polyethylenes
Shear viscosity
Silica
Nanoparticles
Elastic moduli
Extrusion
Polymers
Molecular weight
ultra-high molecular weight polyethylene

Keywords

  • bimodal distribution
  • heterogeneity
  • polyethylene
  • zero shear viscosity

Cite this

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title = "Rheological properties of bimodal polyethylenes produced with silica nanoparticle supported catalysts",
abstract = "The rheological properties of bimodal ultra-high-molecular-weight polyethylenes (UHMWPEs) are investigated with an emphasis on the influence of the catalyst support. Bimodal UHMWPEs were produced in a single reactor with double support (DS) and single support (SS) catalyst systems. Dynamic measurements showed that the SS samples have a higher storage modulus at low frequencies than the DS samples with the same weight average molecular weight. After extrusion, the storage modulus of the bimodal DS samples increased to an identical value. The results indicate that the SS sample has a higher homogeneity than the DS sample. The steady-shear viscosities were measured to determine zero shear viscosities (η0) of the bimodal samples. The results show that the SS samples follow the relation η0 = KMw α with α = 3.19. However, the DS samples exhibit a substantial deviation from this relation especially in the intermediate Mw range around 1000 kg mol−1. The reason for the deviation is attributed to the heterogeneity in DS samples. The results demonstrate that the DS systems do not produce bimodal PEs with an intimate degree of mixing of short and long polymer chains even if silica nanoparticles are used as the support.",
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Rheological properties of bimodal polyethylenes produced with silica nanoparticle supported catalysts. / Liu, Hao (Corresponding author); Troisi, Enrico M.; Goossens, Johannes G.P.; Severn, John R.; Bastiaansen, Cees W.M.

In: Journal of Applied Polymer Science, Vol. 136, No. 21, 47577, 05.06.2019.

Research output: Contribution to journalArticleAcademicpeer-review

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