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Assessing 1,9-Decadiene/Ethylene Copolymerization with Ziegler-Natta Catalyst to Access Long Chain-Branched
Yang Liu1,2, Yawei Qin1,2, Jin-Yong Dong1,2
1CAS Key Laboratory of Engineering Plastics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
ACS Omega
|January 18, 2021
Summary
Ziegler-Natta catalysts can produce long chain-branched polyethylene using 1,9-decadiene. However, high comonomer feeds lead to gelation, limiting practical applications for branched polyethylene synthesis.
Area of Science:
- Polymer Chemistry
- Catalysis
- Materials Science
Background:
- Long chain-branched polyethylene (PE) offers unique material properties.
- Ziegler-Natta catalysis is a key method for PE production.
- Controlling branching in PE remains a significant challenge.
Purpose of the Study:
- To investigate the use of 1,9-decadiene as a comonomer for Ziegler-Natta catalyzed long chain-branched PE synthesis.
- To understand the effect of 1,9-decadiene on catalyst activity and polymer properties.
- To determine the conditions for achieving long chain-branching without undesirable side reactions.
Main Methods:
- Copolymerization of ethylene with 1,9-decadiene using a MgCl2/9,9-bis-(methoxymethyl)fluorine/TiCl4 catalyst and triethylaluminium cocatalyst.
- Analysis of catalyst activity, polyethylene molecular weight, and branching structure.
- Varying 1,9-decadiene feed concentrations to study its impact on polymerization.
Main Results:
- 1,9-Decadiene significantly affected catalyst activity and reduced PE molecular weight.
- The double bonds of 1,9-decadiene exhibited low reactivity during polymerization, especially when attached to the polymer chain.
- Low 1,9-decadiene feeds resulted in minimal pendant vinyl groups without long chain-branching.
- Increased 1,9-decadiene feeds led to long chain-branching but also caused proportional gelation.
Conclusions:
- While 1,9-decadiene can induce long chain-branching in PE via Ziegler-Natta catalysis, its low reactivity and tendency to cause gelation at higher concentrations present limitations.
- Careful control of 1,9-decadiene feed is crucial to balance branching formation and avoid gelation.
- Further research may be needed to optimize conditions or explore alternative comonomers for controlled long chain-branched PE synthesis.
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