Effects of supported metallocene catalyst active center multiplicity on antioxidant-stabilized ethylene homo- and copolymers

Atiqullah, Muhammad; Cibulková, Zuzana; Černá, Andrea; Šimon, Peter; Hussain, Ikram; Al‐Harthi, Mamdouh A.; Anantawaraskul, Siripon

doi:10.1007/s10973-014-4167-7

Cited by 11 publications

(8 citation statements)

References 53 publications

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“…We obtained the catalyst active site type-specific number average molecular weight M ni from the simultaneous deconvolution of MWD and CCD of the assynthesized polyethylenes (table 3). 24,25 Figure 1 compares the copolymerization versus homopolymerization rates of the predicted catalyst active site types. We calculated these rates as reported in the literature.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, we recently modelled the catalyst active centre distribution of a supported metallocene catalyst-(silica/MAO/( n BuCp) 2 ZrCl 2by simultaneous deconvolution of the measured molecular weight and copolymer composition distributions of the resulting polyethylenes, and confirmed the model prediction experimentally (using the differential scanning calorimetry-based successive self-nucleation and annealing (SSA) technique) as well as from the perspective of MAO structural heterogeneity. 24,25 In this study, we applied the above model-predicted parameters to evaluate the active-centre-dependent ethylene homo-and copolymerization rates, as well as the corresponding chain termination rates. This enabled us to study 1-hexene-induced positive comonomer effect and chain transfer phenomenon from a microkinetic mechanistic viewpoint, which, to the best of our knowledge, has not been published earlier.…”

Section: Discussionmentioning

confidence: 99%

“…Properties of the synthesized ethylene homo-and copolymer. 24,25 Experimental a Calculated using the rule of additivity of volumes of amorphous and crystalline phases, and DSCdetermined fractional crystallinity (X c ) :…”

Section: Methodsmentioning

confidence: 99%

“…The procedures related to what has been stated above have been detailed in our recent publications. 24,25…”

Section: Methodsmentioning

confidence: 99%

“…The mathematical development of the aforesaid deconvolution model and the associated computational algorithm are detailed in the literature. [24][25][26][27][28][29]…”

Section: Modelling Of Catalyst Active Centre Distributionmentioning

confidence: 99%

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Ethylene homo- and copolymerization chain-transfers: A perspective from supported ( n BuCp) 2 ZrCl 2 catalyst active centre distribution

et al. 2015

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Polymerization 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/(n BuCp) 2 ZrCl 2-were applied to evaluate the active-centredependent 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 centrespecific molecular weight M ni (for the above homo-and copolymer), as a function of chain transfer probability, p CT i , varied as follows: log p CT i = log(mw ru) − log(M ni) 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.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…The procedures related to what has been stated above have been detailed in our recent publications. 24,25…”

Section: Methodsmentioning

confidence: 99%

“…The mathematical development of the aforesaid deconvolution model and the associated computational algorithm are detailed in the literature. [24][25][26][27][28][29]…”

Section: Modelling Of Catalyst Active Centre Distributionmentioning

confidence: 99%

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Ethylene homo- and copolymerization chain-transfers: A perspective from supported ( n BuCp) 2 ZrCl 2 catalyst active centre distribution

et al. 2015

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Modeling Propylene Polymerization in a Two‐Reactor System: Model Development and Parameter Estimation

Charoenpanich

Anantawaraskul

Soares

et al. 2022

Macro Reaction Engineering

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A series of two reactors is commonly used to produce commercial polypropylene resins to make products with a broad range of microstructures using different feeding policies and/or operating conditions in both reactors. A mathematical model describing the molecular weight distribution (MWD) and yield of polypropylene made with a Ziegler-Natta catalyst in a two-reactor system is developed in this work. A new methodology to estimate the polymerization kinetic parameters combining the simultaneous MWD deconvolution and analysis of polymer yields in both reactors is also proposed. This pragmatic approach can be applied without knowledge of detailed polymerization rates and is, therefore, very convenient to quantify polymerizations in continuous pilot and/or commercial reactors, where such information is generally not available.

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Polyolefin Catalyst Research: A Product‐Driven Industrial Perspective

Atiqullah

Alasiri

2022

The Chemical Record

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This account narrates polyolefin catalyst research at the Research Institute Interdisciplinary Research Center for Refining & Advanced Chemicals (IRCRAC). We particularly address catalyst performance and kinetic evaluation, novelty in supported metallocene catalysts, the apparently absurd residual catalyst structure and solid‐state electronic environment, illustration of supported metallocene catalyst active site distribution thru model and experiment, preparation of spheroidal MgCl2 support, and catalytic synthesis of energy‐saving drag reducing UHMW polymers using local petrochemical feedstock. Each area has been assessed from the product development perspective. Our PO catalyst research aligns with Saudi Arab's Vision 2030 National Strategic Plan (NSP). We also present a circular research concept which shows how product‐driven research with a commercial driving force can significantly advance fundamental PO catalyst chemistry to valuable applications for Saudi Arabia. Finally, we focus on establishing spinoffs using local raw materials. We highlight the role, to be played by researchers, R&D management, and potential investors, to develop the appropriate innovation diffusion culture. The critical need is to understand why an innovation will fail to be marketed. We particularly stress the importance of conducive sociology (environment), psychology (mental state), and mindset (preparedness to make and accept changes) that precede innovation and technology.

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Effects of supported metallocene catalyst active center multiplicity on antioxidant-stabilized ethylene homo- and copolymers

Cited by 11 publications

References 53 publications

Ethylene homo- and copolymerization chain-transfers: A perspective from supported ( n BuCp) 2 ZrCl 2 catalyst active centre distribution

Ethylene homo- and copolymerization chain-transfers: A perspective from supported ( n BuCp) 2 ZrCl 2 catalyst active centre distribution

Modeling Propylene Polymerization in a Two‐Reactor System: Model Development and Parameter Estimation

Polyolefin Catalyst Research: A Product‐Driven Industrial Perspective

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