Polyolefins Journal
With the collaboration of Iran Polymer Society

Tuning the short chain branch distribution of ethylene and 1-hexene copolymers by SiO2-supported silyl chromate catalyst with different Al-alkyl co-catalysts

Document Type : Original research

Authors

Ning Zhao 1
Ruihua Cheng 1
Qi Dong 1
Xuelian He 1
Zhen Liu 1
Shiliang Zhang 1
Minoru Terano 2
Boping Liu 1

1 State Key Laboratory of Chemical Engineering, East China University of Science and Technology, No.130 Meilong Road, Xuhui District, Shanghai, 200237, China

2 School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan

https://doi.org/10.22063/poj.2014.1045
Abstract
SiO2-supported silyl chromate catalyst is an important industrial catalyst for production of high grade HDPE pipe materials. The control of the short chain branch (SCB) distribution using this catalyst system is still a great challenge. In this work, ethylene and 1-hexene copolymers were synthesized using SiO2-supported silyl chromate catalyst combined with triisobutylaluminium (TIBA), triethylaluminium (TEA) and mixed TIBA/TEA at molar ratio 1:1 (TIBA/TEA/1:1) as three different Al-alkyl co-catalysts.The temperature rising elution fractionation (TREF) and successive self-nucleation and annealing (SSA, by DSC) methods were combined to analyze the short chain branch distribution (SCBD) of these ethylene/1-hexene copolymers. The results showed that different types of co-catalyst had a great influence on SCBD of ethylene/1-hexene copolymers. The copolymer produced with TIBA showed better SCBD than the copolymer produced with TEA, and the copolymer produced with TIBA/ TEA/1:1 showed a SCBD in between those with TIBA and TEA.

Keywords

ethylene/1-hexene copolymerization
Al-alkyl co-catalyst
polymerization kinetics
SiO2-supported silyl chromate catalyst
short chain branch distribution
Subjects
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Polyolefins Journal
Volume 1, Issue 2 - Serial Number 2
Autumn 2014
Pages 93-105

  • Receive Date 06 December 2013
  • Revise Date 03 May 2014
  • Accept Date 25 May 2014
  • First Publish Date 01 December 2014

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