Effects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviors

Handle URI:
http://hdl.handle.net/10754/594274
Title:
Effects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviors
Authors:
Atiqullah, Muhammad; Anantawaraskul, Siripon; Emwas, Abdul Hamid M; Al-Harthi, Mamdouh A.; Hussain, Ikram; Ul-Hamid, Anwar; Hossaen, Anwar
Abstract:
Two catalysts, denoted as catalyst 1 [silica/MAO/(nBuCp) 2ZrCl2] and catalyst 2 [silica/nBuSnCl 3/MAO/(nBuCp)2ZrCl2] were synthesized and subsequently used to prepare, without separate feeding of methylaluminoxane (MAO), ethylene homopolymer 1 and homopolymer 2, respectively, and ethylene-1-hexene copolymer 1 and copolymer 2, respectively. Gel permeation chromatography (GPC), Crystaf, differential scanning calorimetry (DSC) [conventional and successive self-nucleation and annealing (SSA)], and 13C nuclear magnetic resonance (NMR) polymer characterization results were used, as appropriate, to model the catalyst active-center distribution, ethylene sequence (equilibrium crystal) distribution, and lamellar thickness distribution (both continuous and discrete). Five different types of active centers were predicted in each catalyst, as corroborated by the SSA experiments and complemented by an extended X-ray absorption fine structure (EXAFS) report published in the literature. 13C NMR spectroscopy also supported this active-center multiplicity. Models combined with experiments effectively illustrated how and why the active-center distribution and the variance in the design of the supported MAO anion, having different electronic and steric effects and coordination environments, influence the concerned copolymerization mechanism and polymer properties, including inter- and intrachain compositional heterogeneity and thermal behaviors. Copolymerization occurred according to the first-order Markovian terminal model, producing fairly random copolymers with minor skewedness toward blocky character. For each copolymer, the theoretical most probable ethylene sequences, nE MPDSC-GT and n E MPNMR-Flory, as well as the weight-average lamellar thicknesses, Lwav DSC-GT and Lwav SSA DSC, were found to be comparable. To the best of our knowledge, such a match has not previously been reported. The percentage crystallinities of the homo- and copolymers increased linearly as a function of LMPDSC-GT. This indicates that the homo- and copolymer chains folded excluding the butyl branch. The results of the present study will contribute to developing future supported metallocene catalysts that will be useful in the synthesis of new grades of ethylene-α-olefin linear low-density polyethylenes (LLDPEs). © 2013 American Chemical Society.
KAUST Department:
Imaging and Characterization Core Lab
Citation:
Atiqullah M, Anantawaraskul S, Emwas A-HM, Al-Harthi MA, Hussain I, et al. (2013) Effects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviors . Ind Eng Chem Res 52: 9359–9373. Available: http://dx.doi.org/10.1021/ie4005139.
Publisher:
American Chemical Society (ACS)
Journal:
Industrial & Engineering Chemistry Research
Issue Date:
10-Jul-2013
DOI:
10.1021/ie4005139
Type:
Article
ISSN:
0888-5885; 1520-5045
Sponsors:
The authors acknowledge the financial support provided by King Abdulaziz City for Science and Technology (KACST) via the Science & Technology Unit at King Fahd University of Petroleum & Minerals (KFUPM) through Project 08-PET90-4 as part of the National Science and Technology Innovation Plan. The technical assistance provided by the Center of Refining & Petrochemicals (CRP), the Center for Engineering Research at Research Institute, the Center of Research Excellence in Petroleum Refining & Petrochemicals (CoRE-PRP), and the Department of Chemical Engineering, KFUPM, Dhahran, Saudi Arabia; the NMR Core Laboratory, King Abdullah University of Science & Technology (KAUST), Thuwal, Saudi Arabia; and the Department of Chemical Engineering, Kasetsart University, Bangkok, Thailand, is also gratefully acknowledged. The technical assistance of Mr. Sagir Adamu is also appreciated.
Appears in Collections:
Articles; Advanced Nanofabrication, Imaging and Characterization Core Lab

Full metadata record

DC FieldValue Language
dc.contributor.authorAtiqullah, Muhammaden
dc.contributor.authorAnantawaraskul, Siriponen
dc.contributor.authorEmwas, Abdul Hamid Men
dc.contributor.authorAl-Harthi, Mamdouh A.en
dc.contributor.authorHussain, Ikramen
dc.contributor.authorUl-Hamid, Anwaren
dc.contributor.authorHossaen, Anwaren
dc.date.accessioned2016-01-19T14:44:55Zen
dc.date.available2016-01-19T14:44:55Zen
dc.date.issued2013-07-10en
dc.identifier.citationAtiqullah M, Anantawaraskul S, Emwas A-HM, Al-Harthi MA, Hussain I, et al. (2013) Effects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviors . Ind Eng Chem Res 52: 9359–9373. Available: http://dx.doi.org/10.1021/ie4005139.en
dc.identifier.issn0888-5885en
dc.identifier.issn1520-5045en
dc.identifier.doi10.1021/ie4005139en
dc.identifier.urihttp://hdl.handle.net/10754/594274en
dc.description.abstractTwo catalysts, denoted as catalyst 1 [silica/MAO/(nBuCp) 2ZrCl2] and catalyst 2 [silica/nBuSnCl 3/MAO/(nBuCp)2ZrCl2] were synthesized and subsequently used to prepare, without separate feeding of methylaluminoxane (MAO), ethylene homopolymer 1 and homopolymer 2, respectively, and ethylene-1-hexene copolymer 1 and copolymer 2, respectively. Gel permeation chromatography (GPC), Crystaf, differential scanning calorimetry (DSC) [conventional and successive self-nucleation and annealing (SSA)], and 13C nuclear magnetic resonance (NMR) polymer characterization results were used, as appropriate, to model the catalyst active-center distribution, ethylene sequence (equilibrium crystal) distribution, and lamellar thickness distribution (both continuous and discrete). Five different types of active centers were predicted in each catalyst, as corroborated by the SSA experiments and complemented by an extended X-ray absorption fine structure (EXAFS) report published in the literature. 13C NMR spectroscopy also supported this active-center multiplicity. Models combined with experiments effectively illustrated how and why the active-center distribution and the variance in the design of the supported MAO anion, having different electronic and steric effects and coordination environments, influence the concerned copolymerization mechanism and polymer properties, including inter- and intrachain compositional heterogeneity and thermal behaviors. Copolymerization occurred according to the first-order Markovian terminal model, producing fairly random copolymers with minor skewedness toward blocky character. For each copolymer, the theoretical most probable ethylene sequences, nE MPDSC-GT and n E MPNMR-Flory, as well as the weight-average lamellar thicknesses, Lwav DSC-GT and Lwav SSA DSC, were found to be comparable. To the best of our knowledge, such a match has not previously been reported. The percentage crystallinities of the homo- and copolymers increased linearly as a function of LMPDSC-GT. This indicates that the homo- and copolymer chains folded excluding the butyl branch. The results of the present study will contribute to developing future supported metallocene catalysts that will be useful in the synthesis of new grades of ethylene-α-olefin linear low-density polyethylenes (LLDPEs). © 2013 American Chemical Society.en
dc.description.sponsorshipThe authors acknowledge the financial support provided by King Abdulaziz City for Science and Technology (KACST) via the Science & Technology Unit at King Fahd University of Petroleum & Minerals (KFUPM) through Project 08-PET90-4 as part of the National Science and Technology Innovation Plan. The technical assistance provided by the Center of Refining & Petrochemicals (CRP), the Center for Engineering Research at Research Institute, the Center of Research Excellence in Petroleum Refining & Petrochemicals (CoRE-PRP), and the Department of Chemical Engineering, KFUPM, Dhahran, Saudi Arabia; the NMR Core Laboratory, King Abdullah University of Science & Technology (KAUST), Thuwal, Saudi Arabia; and the Department of Chemical Engineering, Kasetsart University, Bangkok, Thailand, is also gratefully acknowledged. The technical assistance of Mr. Sagir Adamu is also appreciated.en
dc.publisherAmerican Chemical Society (ACS)en
dc.titleEffects of Supported ( n BuCp) 2 ZrCl 2 Catalyst Active-Center Distribution on Ethylene–1-Hexene Copolymer Backbone Heterogeneity and Thermal Behaviorsen
dc.typeArticleen
dc.contributor.departmentImaging and Characterization Core Laben
dc.identifier.journalIndustrial & Engineering Chemistry Researchen
dc.contributor.institutionCenter for Refining and Petrochemicals, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabiaen
dc.contributor.institutionCenter of Research Excellence in Petroleum Refining and Petrochemicals, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabiaen
dc.contributor.institutionDepartment of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabiaen
dc.contributor.institutionCenter for Engineering Research, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabiaen
dc.contributor.institutionDepartment of Chemical Engineering, Kasetsart Universityc, Jatujak, Bangkok 10900, Thailanden
kaust.authorUl-Hamid, Anwaren
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