Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers

Handle URI:
http://hdl.handle.net/10754/598089
Title:
Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers
Authors:
Atiqullah, Muhammad; Adamu, Sagir; Hossain, Mohammad Mozahar; Al-Harthi, Mamdouh A.; Anantawaraskul, Siripon; Hossaen, Anwar
Abstract:
Two different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst active center multiplicity and polymer crystallization kinetics were modeled. Five separate active center types were predicted, which matched the successive self-nucleation and annealing (SSA) peak temperatures. The predicted crystallinity well matched the differential scanning calorimetric (DSC) values for a single Avrami-Erofeev index, which ranged between 2 and 3 for the polymers experimented. The estimated apparent crystallization activation energy Ea did not vary with cooling rates, relative crystallinity α, and crystallization time or temperature. Therefore, the concept of variable/instantaneous activation energy was not found to hold. Ea linearly increased with the weight average lamellar thickness Lwav DSC-GT; and for each homopolymer, it exceeded that of the corresponding copolymer. Higher Ea, hence slower crystallization, was identified as a pre-requisite to attain higher crystallinity. Crystallization parameters were correlated to polymer backbone parameters, which are influenced by catalyst active center multiplicity. © 2013 Taiwan Institute of Chemical Engineers.
Citation:
Atiqullah M, Adamu S, Hossain MM, Al-Harthi MA, Anantawaraskul S, et al. (2014) Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers. Journal of the Taiwan Institute of Chemical Engineers 45: 1982–1991. Available: http://dx.doi.org/10.1016/j.jtice.2013.11.005.
Publisher:
Elsevier BV
Journal:
Journal of the Taiwan Institute of Chemical Engineers
Issue Date:
Jul-2014
DOI:
10.1016/j.jtice.2013.11.005
Type:
Article
ISSN:
1876-1070
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 Number 08-PET90-4 as part of the National Science and Technology Innovation Plan. The technical assistance provided by the following KFUPM centers—Center of Refining & Petrochemicals (CRP) and Center for Engineering Research at Research Institute, and the Center of Research Excellence in Petroleum Refining & Petrochemicals (CoRE-PRP)—at Dhahran, Saudi Arabia; NMR Core Laboratory, Thuwal, King Abdullah University of Science & Technology (KAUST), Saudi Arabia; and the Department of Chemical Engineering at KFUPM and the Department of Chemical Engineering at Kasetsart University, Thailand is also gratefully acknowledged.
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DC FieldValue Language
dc.contributor.authorAtiqullah, Muhammaden
dc.contributor.authorAdamu, Sagiren
dc.contributor.authorHossain, Mohammad Mozaharen
dc.contributor.authorAl-Harthi, Mamdouh A.en
dc.contributor.authorAnantawaraskul, Siriponen
dc.contributor.authorHossaen, Anwaren
dc.date.accessioned2016-02-25T13:12:28Zen
dc.date.available2016-02-25T13:12:28Zen
dc.date.issued2014-07en
dc.identifier.citationAtiqullah M, Adamu S, Hossain MM, Al-Harthi MA, Anantawaraskul S, et al. (2014) Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers. Journal of the Taiwan Institute of Chemical Engineers 45: 1982–1991. Available: http://dx.doi.org/10.1016/j.jtice.2013.11.005.en
dc.identifier.issn1876-1070en
dc.identifier.doi10.1016/j.jtice.2013.11.005en
dc.identifier.urihttp://hdl.handle.net/10754/598089en
dc.description.abstractTwo different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst active center multiplicity and polymer crystallization kinetics were modeled. Five separate active center types were predicted, which matched the successive self-nucleation and annealing (SSA) peak temperatures. The predicted crystallinity well matched the differential scanning calorimetric (DSC) values for a single Avrami-Erofeev index, which ranged between 2 and 3 for the polymers experimented. The estimated apparent crystallization activation energy Ea did not vary with cooling rates, relative crystallinity α, and crystallization time or temperature. Therefore, the concept of variable/instantaneous activation energy was not found to hold. Ea linearly increased with the weight average lamellar thickness Lwav DSC-GT; and for each homopolymer, it exceeded that of the corresponding copolymer. Higher Ea, hence slower crystallization, was identified as a pre-requisite to attain higher crystallinity. Crystallization parameters were correlated to polymer backbone parameters, which are influenced by catalyst active center multiplicity. © 2013 Taiwan Institute of Chemical Engineers.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 Number 08-PET90-4 as part of the National Science and Technology Innovation Plan. The technical assistance provided by the following KFUPM centers—Center of Refining & Petrochemicals (CRP) and Center for Engineering Research at Research Institute, and the Center of Research Excellence in Petroleum Refining & Petrochemicals (CoRE-PRP)—at Dhahran, Saudi Arabia; NMR Core Laboratory, Thuwal, King Abdullah University of Science & Technology (KAUST), Saudi Arabia; and the Department of Chemical Engineering at KFUPM and the Department of Chemical Engineering at Kasetsart University, Thailand is also gratefully acknowledged.en
dc.publisherElsevier BVen
dc.subjectEthylene-1-hexene copolymer compositional heterogeneityen
dc.subjectInvariable apparent crystallization activation energyen
dc.subjectKinetics of crystallizationen
dc.subjectMetallocene catalysten
dc.subjectModeling of catalyst active site multiplicityen
dc.titleEffects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymersen
dc.typeArticleen
dc.identifier.journalJournal of the Taiwan Institute of Chemical Engineersen
dc.contributor.institutionKing Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabiaen
dc.contributor.institutionKasetsart University, Bangkok, Thailanden
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