High-Temperature Pulsed-Field-Gradient Multidimensional NMR of Polymers

Liu, Weixia; Ray, Dale G.; Rinaldi, Peter L.; Zens, Toby

doi:10.1006/jmre.1999.1868

Cited by 11 publications

(8 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Employing a high-temperature PFG probe extends the use of multidimensional PFG experiments to high-melting and/or low-solubility polymers and materials such as polyethylenes, which must be heated to increase mobility. Spectra with better dispersion and increased signal-to-noise ratios can be obtained, 32 enabling detection of the resonances from microstructures which are present at low occurrence levels in the polymer. With PFG coherence selection, more t 1 increments can be collected with fewer tran- sients per increment to provide a spectrum with better signal-to-noise as well as better resolution in the f 1 dimension.…”

Section: Hmqc and Hmbc 2d Nmr Spectra Of Poly-(ethylene-co-1-octene)mentioning

confidence: 99%

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

Liu¹,

Rinaldi²,

McIntosh³

et al. 2001

Macromolecules

Self Cite

View full text Add to dashboard Cite

Herein are presented the 188.6 MHz 13C NMR spectra (corresponding to 750 MHz 1H resonance frequency) of a series of copolymers from ethylene and 1-octene monomers. These spectra permit the resolution of unique 13C resonances from hexyl chain branches. The 750 MHz high-temperature pulsed field gradient (PFG), heteronuclear multiple quantum correlation (HMQC), and heteronuclear multiple-bond correlation (HMBC) two-dimensional (2D) NMR spectra of ethylene/1-octene copolymers are also presented. Data are presented from a new probe capable of performing high-temperature PFG coherence selection experiments at temperatures typical of those used in many polymer analyses. The performance of this probe is illustrated with PFG−HMQC and PFG−HMBC spectra of copolymers from ethylene/1-octene at 120 °C. Detailed unequivocal proof of the resonance assignments for poly(ethylene-co-1-octene) is reported. The 2D NMR spectra were used to confirm 1H and 13C chemical shift assignments previously determined by empirical methods. Quantitative analyses of the ethylene/1-octene copolymers were also performed.

show abstract

Section: Hmqc and Hmbc 2d Nmr Spectra Of Poly-(ethylene-co-1-octene)mentioning

confidence: 99%

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

Liu¹,

Rinaldi²,

McIntosh³

et al. 2001

Macromolecules

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since the spectra from the terpolymer samples contain resonances characteristic of long sequences of ethylene monomer units, the nomenclature is based on that used to label the atoms in general structure for polyethylene. This is based on the polyethylene nomenclature first defined by Carman 26 and modified by Dorman 27 and Randall 5 and exemplified in a high field NMR study by Liu et al 28 Methylene carbons along the backbone are identified by a pair of Greek letters to indicate the distances to the branches in either direction. Carbons in the side chains are designated by iB n where "i" indicates the position in the branch starting with the methyl in position 1, and the subscript "n" denotes the length of the branch.…”

Section: Resultsmentioning

confidence: 99%

3D NMR Studies of C-Centered n-ad Structures in Poly(ethylene-co-n-butylacrylate-co-¹³C-carbon monoxide) (PolyEBC*)

et al. 2006

Self Cite

View full text Add to dashboard Cite

Three-dimensional HC A C X and HC A C X -HH-TOCSY NMR experiments (J. Magn. Reson. 2004, 168, 352) at 750 MHz have been used to investigate the resonance assignments and monomer sequence distributions of C-centered triads and pentads in poly(ethylene-co-n-butyl acrylate-co-13 C-carbon monoxide), poly(EBC*) terpolymer prepared from 13 C-labeled carbon monoxide. These experiments provide spectra with correlations among mutually coupled atoms with δ CO plotted along the f 1 dimension and δ CA and δ H of adjoining groups plotted along the f 2 and f 3 dimensions, respectively. The correlation among signals in three planes in a 3D NMR spectrum facilitates selective detection of the resonances from the structure fragments near the 13 C labeled ketone carbonyl groups. Moreover, these experiments provide enormous spectral resolution, permitting the identification of numerous unresolved signals that are overlapped in 2D 1 H-13 C HMBC NMR spectrum. The correlation of resonances involving three different nuclei (δ H , δ CA , and δ CO ) provides unambiguous atomic connectivity information in the polymer backbone that facilitates analysis of comonomer composition, stereo-sequence distribution and branching structures. Occasionally, these experiments provide additional proof of the methods adopted to perform chemical shift assignments from 2D HMBC NMR experiments.

show abstract

“…These techniques helped to resolve weak peaks from minor components such as the resonances from the chain ends and short chain branches of synthetic polymers, and to unambiguously make resonance assignments. Recently, Liu et al [7,8] have applied high temperature 1D and 2D NMR experiments to the characterization of polyethylene and ethylene/1-alkene. Employing PFG at high field (750 MHz) permitted resolution of 13 C resonances from minor structural components; unique 13 C spectral assignments were reported in branches up to ten carbons long [9].…”

Section: Introductionmentioning

confidence: 99%

Characterization of n -butyl acrylate centered triads in poly( n -butyl acrylate- co -carbon monoxide- co -ethylene) by isotopic labeling and two dimensional NMR

Monwar

Rinaldi

et al. 2004

Analytical and Bioanalytical Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

High-Temperature Pulsed-Field-Gradient Multidimensional NMR of Polymers

Cited by 11 publications

References 18 publications

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

3D NMR Studies of C-Centered n-ad Structures in Poly(ethylene-co-n-butylacrylate-co-¹³C-carbon monoxide) (PolyEBC*)

Characterization of n -butyl acrylate centered triads in poly( n -butyl acrylate- co -carbon monoxide- co -ethylene) by isotopic labeling and two dimensional NMR

Contact Info

Product

Resources

About

High-Temperature Pulsed-Field-Gradient Multidimensional NMR of Polymers

Cited by 11 publications

References 18 publications

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

Poly(ethylene-co-1-octene) Characterization by High-Temperature Multidimensional NMR at 750 MHz

3D NMR Studies of C-Centered n-ad Structures in Poly(ethylene-co-n-butylacrylate-co-13C-carbon monoxide) (PolyEBC*)

Characterization of n -butyl acrylate centered triads in poly( n -butyl acrylate- co -carbon monoxide- co -ethylene) by isotopic labeling and two dimensional NMR

Contact Info

Product

Resources

About

3D NMR Studies of C-Centered n-ad Structures in Poly(ethylene-co-n-butylacrylate-co-¹³C-carbon monoxide) (PolyEBC*)