A practical criterion for synthesizing ethylen-1-butene copolymer in powder form in slurry polymerization with a Ziegler-Natta catalyst and predicting its incorporated 1-butene

Document Type : Original research

Authors

1 Polymerization Engineering Department, Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14975/112, Tehran, Iran

2 Department of Plastics, Faculty of Polymer Processing, Iran Polymer and Petrochemical Institute, PO Box 14965/115, Tehran, Iran

Abstract

The concentration of ethylene and 1-butene in n-hexane as polymerization media was calculated at five different pressure levels (4, 6, 8, 10, and 12 bar) and four different 1-butene concentrations (0.13, 0.26, 0.39, and 0.52 mol/L) in n-hexane at T= 80°C using the Peng-Robinson thermodynamic equation of state. Some combinations of conditions were selected to perform the copolymerization reaction in the presence of an industrial TiCl4/MgCl2 Ziegler-Natta catalyst. The forms of the synthesized products were visually and qualitatively classified as either powder or sticky. The percentage of incorporated 1-butene comonomer into the polyethylene chains was analyzed using calibrated FTIR tests. It was shown that for ethylene/1-butene concentration ratios (β) in n-hexane above approximately 1.80, the product forms as a powder. For values below 1.30 threshold, the product was sticky. Thus, this ratio could be used as a criterion for selecting the proper combination of copolymerization pressure and 1-butene concentration when aiming to achieve a powdered form of the product. It was shown that β has a strong correlation with the weight percentage of 1-butene in the final LLDPE polymer. Therefore it can be used as an accurate prediction for wt.% of incorporated 1-butene into the LLDPE chain within the studied concentration ranges with the specific catalyst system utilized.

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References

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Polyolefins Journal
Volume 10, Issue 4 - Serial Number 22
November 2023
Pages 243-251

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History

  • Receive Date: 31 August 2023
  • Revise Date: 18 October 2023
  • Accept Date: 28 October 2023

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