Metallocene-catalyzed ethylene−α-olefin isomeric copolymerization: A perspective from hydrodynamic boundary layer mass transfer and design of MAO anion
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ArticleAuthors
Adamu, SagirAtiqullah, Muhammad
Malaibari, Zuhair O.
Al-Harthi, Mamdouh A.
Emwas, Abdul-Hamid M.
Ul-Hamid, Anwar
KAUST Department
Imaging and Characterization Core LabNMR
Date
2015-11-28Online Publication Date
2015-11-28Print Publication Date
2016-03Permanent link to this record
http://hdl.handle.net/10754/595298
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This study reports a novel conceptual framework that can be easily experimented to evaluate the effects of hydrodynamic boundary layer mass transfer, methylaluminoxane (MAO) anion design, and comonomer steric hindrance on metallocene-catalyzed ethylene polymerization. This approach was illustrated by conducting homo- and isomeric copolymerization of ethylene with 1-hexene and 4-methyl-1-pentene in the presence of bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, using (i) MAO anion 1 (unsupported [MAOCl2]−) and pseudo-homogeneous reference polymerization, and (ii) MAO anion 2 (supported Si−O−[MAOCl2]−) and in-situ heterogeneous polymerization. The measured polymer morphology, catalyst productivity, molecular weight distribution, and inter-chain composition distribution were related to the locus of polymerization, comonomer effect, in-situ chain transfer process, and micromixing effect, respectively. The peak melting and crystallization temperatures and %crystallinity were mathematically correlated to the parameters of microstructural composition distributions, melt fractionation temperatures, and average lamellar thickness. These relations showed to be insightful. The comonomer-induced enchainment defects and the eventual partial disruption of the crystal lattice were successfully modeled using Flory and Gibbs–Thompson equations. The present methodology can also be applied to study ethylene−α-olefin copolymerization, performed using MAO-activated non-metallocene precatalysts.Citation
Metallocene-catalyzed ethylene−α-olefin isomeric copolymerization: A perspective from hydrodynamic boundary layer mass transfer and design of MAO anion 2015 Journal of the Taiwan Institute of Chemical EngineersPublisher
Elsevier BVAdditional Links
http://linkinghub.elsevier.com/retrieve/pii/S1876107015004721ae974a485f413a2113503eed53cd6c53
10.1016/j.jtice.2015.10.031