Effects of a vanadium post-metallocene catalyst-induced polymer backbone inhomogeneity on UV oxidative degradation of the resulting polyethylene film

Atiqullah, Muhammad; Winston, Matthew S.; Bercaw, John E.; Hussain, Ikram; Fazal, Atif; Al‐Harthi, Mamdouh A.; Emwas, Abdul Hamid; Khan, Masihullah Jabarulla; Hossaen, Anwar

doi:10.1016/j.polymdegradstab.2012.03.042

Cited by 17 publications

(19 citation statements)

References 89 publications

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“…A differential scanning calorimeter (DSC Q2000, Texas Instrument) measured the peak melting ( T pm ) and crystallization ( T pc ) temperatures, and percent crystallinity ( X c ) of the experimental i ‐PP and i ‐PP‐GnP nanocomposites, following the procedure reported in the literature . The DSC instrument was calibrated using indium.…”

Section: Methodsmentioning

confidence: 99%

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

et al. 2020

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Crystallization occurs in processing i-PP-GnP nanocomposites, and these nanocomposites have the potential to replace traditional fillers and be used to fabricate advanced materials and technology. Therefore, this subject was comprehensively investigated by applying a recent crystallization model, non-isothermal DSC experiments, Raman spectroscopy, and WAXRD. The multi-layer GnPinduced nucleation and the crystal growth rates were modelled. The overall modelling effort generated new insights, results, and explanations. This study confirmed and elucidated, or refuted several published conclusions. It has also been reported that the present model can pursue differences in catalyst-mediated i-PP backbone defects (stereo and regio) by simulating the relative crystallization profile and determining the crystallization kinetic triplet (n, k o , and E a ). The multiple roles played by GnP were underscored, which exceed what the related literature currently reports. The Raman and XRD work revealed the interaction between GnP and i-PP. The shear-induced dispersion of GnP that occurs during extrusion significantly affected i-PP crystal size distribution. The present approach can also assess the effects of catalyst type and structure, and backbone defect types and their distribution on the non-isothermal crystallization of, in general, polyolefin blends and nanocomposites.

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Section: Methodsmentioning

confidence: 99%

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

et al. 2020

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“…The experimental procedure reported in the literature was followed. [38][39][40] The data were acquired for each cycle and handled using the TA explorer software. The measured X c was subsequently used to calculate the polymer material density q polym , following the rule of additivity of volumes of polyethylene amorphous and crystalline phases:…”

Section: Thermal Properties Density and Copolymer Melt Fractionationmentioning

confidence: 99%

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

et al. 2016

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The judicious design of methylaluminoxane (MAO) anions expands the scope for developing industrial metallocene catalysts. Therefore, the effects of MAO anion design on the backbone structure, melt behavior, and crystallization of ethylene24-methyl-1-pentene (E24M1P) copolymer were investigated. Ethylene was homopolymerized, as well as copolymerized with 4M1P, using (1) , opposite to the supported analogue, acted as a co-chain transfer agent with 4M1P. The modeling of polyethylene melting and crystallization kinetics, including critical crystallite stability, produced insightful results. This study especially illustrates how branched polyethylene can be prepared from ethylene alone using particularly one metallocene-MAO ion pair, and how a compound, that functionalizes silica as well as terminates the chain, can synthesize ethylene2a-olefin copolymers with novel structures. Hence, it unfolds prospective future research niches in polyethyne systhesis.

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“…Such identification is not possible with the 1D approach. For example, various homo-nuclear 2D 1 H-1 H-NMR experiments, including total correlation spectroscopy (TOCSY) [225][226][227][228][229][230][231][232][233][234], correlation spectroscopy (COSY) [219,[234][235][236][237][238][239][240][241], and heteronuclear experiments such as 1 H, 13 C-single quantum coherence ( 1 H-13 C-HSQC) and heteronuclear multiple bond correlation (HMBC) have been routinely used in to assign protein signals and to study protein interactions with ligands in drugs and small molecules [242]. Here, we present heteronuclear single-quantum coherence spectroscopy (HSQC) as an example of the most powerful approaches used to assign signals and to probe ligand protein interactions [243].…”

Section: Two-dimensional Nmr Spectroscopymentioning

confidence: 99%

Using NMR spectroscopy to investigate the role played by copper in prion diseases

et al. 2020

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Prion diseases are a group of rare neurodegenerative disorders that develop as a result of the conformational conversion of normal prion protein (PrP C) to the disease-associated isoform (PrP Sc). The mechanism that actually causes disease remains unclear. However, the mechanism underlying the conformational transformation of prion protein is partially understood-in particular, there is strong evidence that copper ions play a significant functional role in prion proteins and in their conformational conversion. Various models of the interaction of copper ions with prion proteins have been proposed for the Cu (II)-binding, cell-surface glycoprotein known as prion protein (PrP). Changes in the concentration of copper ions in the brain have been associated with prion diseases and there is strong evidence that copper plays a significant functional role in the conformational conversion of PrP. Nevertheless, because copper ions have been shown to have both a positive and negative effect on prion disease onset, the role played by Cu (II) ions in these diseases remains a topic of debate. Because of the unique properties of paramagnetic Cu (II) ions in the magnetic field, their interactions with PrP can be tracked even at single atom resolution using nuclear magnetic resonance (NMR) spectroscopy. Various NMR approaches have been utilized to study the kinetic, thermodynamic, and structural properties of Cu (II)-PrP interactions. Here, we highlight the different models of copper interactions with PrP with particular focus on studies that use NMR spectroscopy to investigate the role played by copper ions in prion diseases.

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Effects of a vanadium post-metallocene catalyst-induced polymer backbone inhomogeneity on UV oxidative degradation of the resulting polyethylene film

Cited by 17 publications

References 89 publications

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

Using NMR spectroscopy to investigate the role played by copper in prion diseases

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Effects of a vanadium post-metallocene catalyst-induced polymer backbone inhomogeneity on UV oxidative degradation of the resulting polyethylene film

Cited by 17 publications

References 89 publications

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

Non‐isothermal crystallization of Ziegler Natta i‐PP‐graphene nanocomposite: DSC and new model prediction

(nBuCp)2ZrCl2‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

Using NMR spectroscopy to investigate the role played by copper in prion diseases

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(ⁿBuCp)₂ZrCl₂‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization