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dc.contributor.authorAtiqullah, Muhammad
dc.contributor.authorAl-Harthi, Mamdouh A.
dc.contributor.authorAnantawaraskul, Siripon
dc.contributor.authorEmwas, Abdul-Hamid M.
dc.date.accessioned2015-08-03T12:33:26Z
dc.date.available2015-08-03T12:33:26Z
dc.date.issued2015-05-24
dc.identifier.citationATIQULLAH, M., AL-HARTHI, M. A., ANANTAWARASKUL, S., & EMWAS, A.-H. M. (2015). Ethylene homo- and copolymerization chain-transfers: A perspective from supported ( n BuCp) 2 ZrCl 2 catalyst active centre distribution. Journal of Chemical Sciences, 127(4), 717–728. doi:10.1007/s12039-015-0828-8
dc.identifier.issn09743626
dc.identifier.doi10.1007/s12039-015-0828-8
dc.identifier.urihttp://hdl.handle.net/10754/564130
dc.description.abstractPolymerization chain termination reactions and unsaturation of the polymer backbone end are related. Therefore, in this study, the parameters resulting from the modelling of the active centre distribution of the supported catalyst - silica/MAO/(nBuCp)2ZrCl2 - were applied to evaluate the active-centre-dependent ethylene homo- and copolymerization rates, as well as the corresponding chain termination rates. This approach, from a microkinetic mechanistic viewpoint, elucidates better the 1-hexene-induced positive comonomer effect and chain transfer phenomenon. The kinetic expressions, developed on the basis of the proposed polymerization mechanisms, illustrate how the active site type-dependent chain transfer phenomenon is influenced by the different apparent termination rate constants and momoner concentrations. The active centre-specific molecular weight M ni (for the above homo- and copolymer), as a function of chain transfer probability, p CTi, varied as follows: log (p C Ti) = log (mwru) - log (Mn i), where mw ru is the molecular weight of the repeat unit. The physical significance of this finding has been explained. The homo- and copolymer backbones showed all the three chain end unsaturations (vinyl, vinylidene, and trans-vinylene). The postulated polymerization mechanisms reveal the underlying polymer chemistry. The results of the present study will contribute to develop in future supported metallocene catalysts that will be useful to synthesize polyethylene precursors having varying chain end unsaturations, which can be eventually used to prepare functional polyethylenes. [Figure not available: see fulltext.] © 2015 Indian Academy of Sciences.
dc.publisherSpringer Nature
dc.subjectactive centre distribution
dc.subjectchain termination probability.
dc.subjectethylene-1-hexene chain end unsaturation
dc.subjectMetallocene catalyst
dc.subjectMWD and CCD deconvolution
dc.titleEthylene homo- and copolymerization chain-transfers: A perspective from supported (n BuCp) 2 ZrCl 2 catalyst active centre distribution
dc.typeArticle
dc.contributor.departmentAdvanced Nanofabrication, Imaging and Characterization Core Lab
dc.contributor.departmentNMR
dc.identifier.journalJournal of Chemical Sciences
dc.contributor.institutionCenter for Refining and Petrochemicals, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
dc.contributor.institutionDepartment of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
dc.contributor.institutionDepartment of Chemical Engineering, Kasetsart University, Jatujak, Bangkok, Thailand
kaust.personEmwas, Abdul-Hamid M.
dc.date.published-online2015-05-24
dc.date.published-print2015-04


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