Cover Picture: Macromol. Chem. Phys. 4/2006

Klimke, Katja; Parkinson, Matthew; Piel, C.; Kaminsky, Werner; Spieß, Hans Wolfgang; Wilhelm, Manfred

doi:10.1002/macp.200690004

Cited by 29 publications

(55 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An early study was reported by Hatfield et al using a 200 MHz spectrometer ( 1 H resonance), [34,35] followed by intensive works of Wilhelm, Kaminsky and their co-workers. [33,36,37] Compared (5 of 20) 1600012 to the solution NMR, which has a sample concentration less than 20 wt%, the melt and solid-state 13 C NMR generate a higher sample filling factor, resulting in a higher sensitivity towards the presence of sparsely branched side chains and end groups in POs. This technique currently allows the characterization of branch lengths up to 16 carbons.…”

Section: Ch(b ) Ch(b )mentioning

confidence: 99%

See 1 more Smart Citation

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

Liu

Wang

et al. 2016

Macro Reaction Engineering

View full text Add to dashboard Cite

Synthesis and characterization of long-chain branched polyolefins has been an important research topic for both academic and industrial researchers for many decades. This is particularly true since the discovery and successful commercialization of the constrained geometry catalyst systems in 1990s. The type of single site catalysts allows control in the synthesis and the precision in the characterization. Long-chain branched polyolefins exhibit improved melt processability, such as higher melt strength and better shear thinning, compared to their linear counterparts having the same molecular weight and distribution. In the previous papers, the catalyst systems and reaction conditions for the controlled synthesis of long-chain branched polyolefins have been reviewed. This paper aims at summarizing the literatures pertinent to the precise characterization of long-chain branched polyolefins. The major methods of long-chain branching characterization include: nuclear magnetic resonance, gel permeation chromatography, rheometry, dynamical mechanical analysis, differential scanning calorimetry, neutron scattering, and Fourier transform infrared spectroscopy. Recent progresses of these characterization methods, as well as their advantages and limitations, have been discussed in details.

show abstract

Section: Ch(b ) Ch(b )mentioning

confidence: 99%

“…[37] In addition, the measurement acquisition times are greatly reduced. LCBD of 7-8 branches per 100 000 CH 2 groups can be determined by melt-state NMR in 13 h, [36] which represents a vast improvement over the multiday acquisitions required for the solution NMR.…”

Section: Ch(b ) Ch(b )mentioning

confidence: 99%

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

Liu

Wang

et al. 2016

Macro Reaction Engineering

View full text Add to dashboard Cite

show abstract

“…n c stands for the molar comonomer content determined from melt-state NMR spectroscopy. [33,34] Results and Discussion…”

Section: Samplesmentioning

confidence: 99%

Correlations between the Shape of Viscosity Functions and the Molecular Structure of Long‐Chain Branched Polyethylenes

Stadler

Münstedt

2009

Macro Materials & Eng

View full text Add to dashboard Cite

The viscosity functions of long‐chain branched metallocene‐catalyzed ethene homopolymers and copolymers (LCB‐mPE) were described by an extended Carreau‐Yasuda model. The two characteristic relaxation times, λ1 and λ2, and the slope of the viscosity function between these two characteristic relaxation times can be correlated to the zero shear‐rate viscosity, η0, and the molar mass $\overline M _{\rm w} $. The characteristic relaxation times, λ1 and λ2 (describing the main curvatures of the viscosity function) exhibit a power law dependency on the molar mass, $\overline M _{\rm w} $. The parameterization of the viscosity function can be used for a molecular characterization and flow simulations of various kinds.magnified image

show abstract

“…Here T C 1 values of branches containing six and more carbons were determined using an optimised melt-state MAS NMR method [15,16] allowing rapid determination of relaxation parameters.…”

Section: Full Papermentioning

confidence: 99%

“…For further details of the optimised melt-state MAS method the reader is directed to the literature. [15,21,22] Melt-state spin-lattice relaxation times were measured using both inversion-recovery and saturation-recovery experiments. A combination of 16 dummy scans and 64 real scans were used per t 1 delay to compensate for NOE and saturation effects.…”

Section: Experimental Partmentioning

confidence: 99%

Effect of Branch Length on ¹³C NMR Relaxation Properties in Molten Poly[ethylene‐co‐(α‐olefin)] Model Systems

Parkinson

Klimke

Spiess

et al. 2007

Macro Chemistry & Physics

Self Cite

View full text Add to dashboard Cite

The potential of branch length discrimination for branches containing six and more carbons via bulk NMR relaxation properties in the melt‐state has been explored. A systematic increase in the 13C spin‐lattice relaxation time (T) of the terminal branch carbons 1 and 2 was observed when the branch increased from 6 to 16 carbons in length. The measurement of T via inversion recovery at high‐field showed the most reliable data. The effects of saturation and NOE were addressed by using recycle delays longer than 5 × T and the use of the saturation recovery was found to be unsatisfactory. All nuclear relaxation times were determined in a highly time efficient manner using a previously developed melt‐state MAS NMR method.magnified image

show abstract

Cover Picture: Macromol. Chem. Phys. 4/2006

Abstract: Cover: Time-efficient quantification of very low branch content in polyethylene using optimised melt-state 13 C NMR under magicangle spinning. Concentrations of 7-8 branches per 100 000 CH 2 groups were determined in only 13 h.

Cited by 29 publications

References 0 publications

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

Correlations between the Shape of Viscosity Functions and the Molecular Structure of Long‐Chain Branched Polyethylenes

Effect of Branch Length on ¹³C NMR Relaxation Properties in Molten Poly[ethylene‐co‐(α‐olefin)] Model Systems

Contact Info

Product

Resources

About

Cover Picture: Macromol. Chem. Phys. 4/2006

Abstract: Cover: Time-efficient quantification of very low branch content in polyethylene using optimised melt-state 13 C NMR under magicangle spinning. Concentrations of 7-8 branches per 100 000 CH 2 groups were determined in only 13 h.

Cited by 29 publications

References 0 publications

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

A Comprehensive Review on Controlled Synthesis of Long‐Chain Branched Polyolefins: Part 3, Characterization of Long‐Chain Branched Polymers

Correlations between the Shape of Viscosity Functions and the Molecular Structure of Long‐Chain Branched Polyethylenes

Effect of Branch Length on 13C NMR Relaxation Properties in Molten Poly[ethylene‐co‐(α‐olefin)] Model Systems

Contact Info

Product

Resources

About

Effect of Branch Length on ¹³C NMR Relaxation Properties in Molten Poly[ethylene‐co‐(α‐olefin)] Model Systems