Complementarity of universal calibration SEC and 13C NMR in determining the branching state of polyethylene

Striegel, André M.; Krejsa, M. R.

doi:10.1002/1099-0488(20001201)38:23<3120::aid-polb130>3.0.co;2-1

Cited by 53 publications

(21 citation statements)

References 30 publications

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“…[14,15] Commonly, differential scanningcalorimetry (DSC), [13,16] triple-detection gel permeation chromatography (GPC) [17][18][19] and rheology [14,[20][21][22][23][24][25][26][27] are used for branch determination. Although these techniques may be very sensitive to the presence of branching, they only provide qualitative insight into the degree of branching.…”

Section: Introductionsupporting

confidence: 87%

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy

Klimke

Parkinson

Piel

et al. 2006

Macro Chemistry & Physics

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Summary: Quantitative branch determination in polyolefins by melt‐state NMR has been investigated paying particular attention to sensitivity per unit time. Comparison of spectra obtained using spectrometers operating at 700, 500 and 300 MHz 1H Larmor frequency, with 4 and 7 mm MAS probeheads, showed that the best sensitivity was achieved at 500 MHz using a 7 mm 13C1H optimised high‐temperature probehead. For materials available in large quantities static melt‐state NMR, using large‐diameter detection coils at 300 MHz, was shown to produce comparable results to melt‐state MAS measurements in less time. Artificial line broadening, introduced by FID truncation, was reduced by the use of π pulse‐train heteronuclear dipolar‐decoupling. This decoupling method, when combined with a higher duty‐cycle, allowed for the whole FID to be acquired. Optimised methods have been applied to the characterisation of short‐chain branching (SCB) in polyethylene‐ and poly(propylene)‐co‐α‐olefins with varying comonomer incorporation. Long‐chain branch (LCB) concentrations of 8 branches per 100 000 CH2 were quantified for an industrial ‘linear’ polyethylene in 13 h, with a signal‐to‐noise ratio of 10 for the α branch site used. The use of J‐coupling mediated polarisation transfer techniques were also shown to be viable for branch quantification in the melt‐state.An example of the time efficient quantification of very low branch contents in polyethylene using optimised 13C melt‐state NMR under magic‐angle spinning. Concentrations of 7–8 branches per 100 000 CH2 groups were determined in only 13 h.magnified imageAn example of the time efficient quantification of very low branch contents in polyethylene using optimised 13C melt‐state NMR under magic‐angle spinning. Concentrations of 7–8 branches per 100 000 CH2 groups were determined in only 13 h.

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Section: Introductionsupporting

confidence: 87%

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy

Klimke

Parkinson

Piel

et al. 2006

Macro Chemistry & Physics

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“…[21] The position information of methine peaks could also be used in this analysis. [22][23][24][25] Rinaldi et al [26] provided an indepth study and observed chemical shift differences of 0.003-0.007 ppm between the peak positions of CH(B 6 ) (38.283 ppm), CH(B 8 ) (38.286 ppm), and CH(B 10 ) (38.293 ppm) in 188.6 MHz 13 C NMR spectra. Such differences could be enhanced by an order of magnitude through adjusting temperature and sample concentration.…”

Section: Nmrmentioning

confidence: 53%

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

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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.

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“…Because the Mark-Houwink plot of log [] versus log M is normally less noisy than the conformation log-log plot of R g versus M, SEC/ VISC is generally a more sensitive method than SEC/ MALS for determining the presence of LCB (8). Figure 5 is an example of a Mark-Houwink plot used to detect LCB in two polyethylene (PE) samples, one linear and one branched (20). Because LCB tends to manifest more markedly in polymers with increasing M, the slope of the Mark-Houwink plot of the branched PE decreases with increasing M, whereas the slope of the linear PE remains constant as a function of M. The d f can also be calculated from SEC/ VISC data using the relation d f = 3/(1 + a), in which a is the slope of the Mark-Houwink plot (8,11).…”

Section: Viscometrymentioning

confidence: 99%

Multiple Detection in Size-Exclusion Chromatography of Macromolecules

Striegel¹

2005

Anal. Chem.

116

101

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Chemical and physical detectors characterize the distributions of macromolecular parameters that have a critical effect on the end product.S ynthesizing polymers is not as exact a science as we would like it to be. Natural syntheses and even well-controlled laboratory syntheses often yield macromolecules that vary in length, molar mass, branching, chemical composition, and other properties. Characterizing these properties and their distributions is important because of their critical effect on end-use structure-property relations and, hence, on the end product itself. The most commonly studied properties are the molar mass averages (M n , M w , M z , etc.) and the molar mass distribution (MMD). Various processing characteristics of macromolecules can be related to the individual averages, for example, flow properties and brittleness (related to M n ) and flex life and stiffness (related to M z ). Similarly, properties such as tensile strength and abrasion resistance tend to increase as MMD narrows, and properties such as elongation and yield strength tend to increase as MMD broadens.During the past four decades, size-exclusion chromatography (SEC) has been established as the premier method for characterizing M averages and the distribution of natural and

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Complementarity of universal calibration SEC and 13C NMR in determining the branching state of polyethylene

Cited by 53 publications

References 30 publications

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy

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

Multiple Detection in Size-Exclusion Chromatography of Macromolecules

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Complementarity of universal calibration SEC and 13C NMR in determining the branching state of polyethylene

Cited by 53 publications

References 30 publications

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State 13C NMR Spectroscopy

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State 13C NMR Spectroscopy

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

Multiple Detection in Size-Exclusion Chromatography of Macromolecules

Contact Info

Product

Resources

About

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy

Optimisation and Application of Polyolefin Branch Quantification by Melt‐State ¹³C NMR Spectroscopy