Mark–Houwink–Staudinger–Sakurada Constants

Zeng, Wu-Lan; Du, Yumin; Xue, Yongpeng; Frisch, H.

doi:10.1007/978-0-387-69002-5_17

Cited by 14 publications

(12 citation statements)

References 127 publications

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“… Reaction conditions: 40 °C, 1 bar ethylene pressure, 30 min, 100 mL n ‐heptane, solid support: SiO 2 , 1 mmol Triisobutylaluminum, 2 μmol [Cr], 2 mmol MAO, a=g PE mmol −1 h −1 bar −1 , b: intrinsic viscosity, c: Mv calculated with Mark‐Houwink equation from intrinsic viscosity with K =6.2 ⋅ 10 −4 ⋅ dL g −1 α [41] =0.7, d: crystallinity of PE. …”

Section: Resultsmentioning

confidence: 99%

“… Reaction conditions: 40 °C, 1 bar of ethylene, 30 min, 100 mL of n ‐heptane, 2 μmol [Cr], 2 mmol MAO, solid support: SiO 2 , co‐monomer: 1‐hexene, 1 mmol Triisobutylaluminum, a=g PE mmol −1 h −1 bar −1 , b: intrinsic viscosity, c: Mv calculated with Mark‐Houwink equation from intrinsic viscosity with K =6.2 ⋅ 10 −4 ⋅ dL g −1 α [41] =0.7, d: 1‐hexene content determined by 1 H NMR spectroscopy of PE in tetrachloroethane at 120 °C, e: crystallinity of PE. …”

Section: Resultsmentioning

confidence: 99%

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The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts

Hansen

Wadepohl

Enders

2021

Chemistry A European J

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The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogenchromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron-donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal centre without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para-amino groups to the chelating pyridine or quinoline, respectively. Combining electron-rich indenyl ligands with para-amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerisation catalysts. The resulting polymers are of ultra-high molecular weight and the ability of the catalysts to incorporate comonomers is also very high.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts

Hansen

Wadepohl

Enders

2021

Chemistry A European J

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“… a Conditions: 40 °C, 1 bar, 30 min, 100 mL of toluene, 2 μmol of [Cr], 2 mmol of MAO. b Supported catalyst, 100 mL of n -heptane, 1 mmol of triisobutylaluminum. c Supported catalyst, 110 mL of n -heptane, 1 mmol of triisobutylaluminum 5 bar of ethylene pressure. d GPC analysis not performed due to very high intrinsic viscosity. e M v calculated with Mark–Houwink equation from intrinsic viscosities with K = 6.2 × 10 –4 dL g –1 and α = 0.7 …”

Section: Resultsmentioning

confidence: 99%

“… e M v calculated with Mark–Houwink equation from intrinsic viscosities with K = 6.2 × 10 –4 dL g –1 and α = 0.7 …”

Section: Resultsmentioning

confidence: 99%

Improving 1-Hexene Incorporation of Highly Active Cp–Chromium-Based Ethylene Polymerization Catalysts

et al. 2016

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Single-site chromium catalysts for olefin polymerization with donor functionalized cyclopentadienyl (Cp) ligands have been modified in order to improve their incorporation ability for the comonomer 1-hexene into the polymer chain under maintenance of their very high catalytic activities. A trimethylsilyl substituent in combination with a fused thiophene ring at the Cp ligand has been identified as the best ligand so far, leading to a doubling in 1-hexene incorporation and polyethylene (PE) with up to 27% 1-hexene content (by weight) has been obtained. The complexes lead to PE with molecular weight in the range of 50 000 to 800 000 g mol −1 when used in homogeneous solution, however after supporting the complex on silica ultrahigh molecular weight polyethylene (UHMW-PE) is formed with 9.9% of 1-hexene incorporated into the chain. Although other known catalysts incorporate even more 1-hexene, the presented system is different as it combines considerable α-olefin incorporation with very high polymer molecular weights and very high catalytic activity. These improved single-site chromium catalysts maintain their advantageous properties on silica as solid support which makes them good candidates for their application in industrial processes for the synthesis of polyethylene materials with advanced properties.

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“…Shi et al calculated the M w of the thermoplastic starch as (1.48 ± 0.19) × 10 6 g mol −1 using a static laser light scattering. In light of the discussion made in these studies, intrinsic viscosity and molecular weight of the most promising biocomposite film were calculated as 0.1973 dL g −1 and 46590.64 g mol −1 , respectively, by using Mark–Houwink constants ( K = 13.2 × 10 −3 mL g −1 and a = 0.68) given by Zeng et al The most promising biocomposite film with these properties seems to fulfill the requirements for being a packaging material with the needed texture structure and mechanical integrity. This is already indicated by a long‐term exposure (1 month) at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Orange peel‐derived pectin jelly and corn starch‐based biocomposite film with layered silicates

Çokaygil

Banar

Seyhan

2014

J of Applied Polymer Sci

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Orange peel‐derived pectin jelly/corn starch‐based biocomposite films with and without layered silicates (LSs) were prepared using melt extrusion followed by film die casting. To enhance interfacial compatibility, corn starch and LSs were chemically modified. Regardless of chemical modification or LS weight content, different pectin jelly‐to‐starch weight ratios (63/37, 60/40, 57/43, and 54/46) were considered to formulate the ingredients of biocomposite films in light of Taguchi‐based predictions. X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), scanned electron microscopy (SEM) and transmission electron microscopy (TEM) were systematically used to characterize corn starch, LSs, and biocomposite films. Among all the films considered, pectin jelly/modified (15%) starch‐based biocomposite film (54/46 w/w) containing 0.25 wt % of pristine LSs was found to be the most promising in terms of texture structure and mechanical integrity. Furthermore, creep recovery, hydrophobicity, and water vapor and oxygen gas transmission rates of the most promising biocomposite film were experimentally determined. Based on the findings obtained, the overall performance of the biocomposite film was evaluated and weighed against the overall performance of a low‐density polyethylene film. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40654.

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Mark–Houwink–Staudinger–Sakurada Constants

Cited by 14 publications

References 127 publications

The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts

The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts

Improving 1-Hexene Incorporation of Highly Active Cp–Chromium-Based Ethylene Polymerization Catalysts

Orange peel‐derived pectin jelly and corn starch‐based biocomposite film with layered silicates

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