Microstructure and Composition of Ethylene−Carbon Monoxide Copolymers by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Cox, Frederick J.; Qian, Kuangnan; Patil, and Abhimanyu O.; Johnston, Murray V.

doi:10.1021/ma0351367

Cited by 10 publications

(6 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, if the A and B polymers are polystyrene (104 g/mol) and poly(α-methylstyrene) (118 g/mol), then k A and k B are both 1. , If, however, they are polyisobutylene (56 g/mol) and poly(α-methylstyrene) (118 g/mol), then k A is 2 and k B is 1, and, in an extreme example, if they are polystyrene (104 g/mol) and polyisoprene (68 g/mol), then k A is 2 and k B is 3 . Of course, if the terms in the expression in eq are exactly equal within the resolution of the sample and the MS instrument (say within a few g/mol or less), such as with polyethylene (28 g/mol) and poly(carbon monoxide) (28 g/mol), then δ is 0, there will be no minor peak spacing, and there will be no peak clusters because all the peaks in a given potential cluster will overlap.…”

Section: Resultsmentioning

confidence: 99%

On the Origin of the Major Peak Cluster Spacing in the Mass Spectra of Copolymers

2013

View full text Add to dashboard Cite

Mass spectrometry (MS) is a uniquely informative technique in the characterization of copolymers, where spectra prominently feature peak clustering. The spacing of these clusters, in general, is dominated by the spacing of one repeat unit, and contained herein is the theory to explain this observation. Extension of this theory also explains the more subtle observation that, even though the spacing is generally that of one unit, occasionally, the spacing between the maxima of adjacent clusters shifts by that of the other unit. Furthermore, the theory predicts that, in the low molecular weight region of the spectrum, there is a total switch to the spacing of the other unit along with asymmetric peak clusters that have a “sawtooth” shape. The analysis uses the Gaussian, log–normal, and Schulz–Zimm models as well as the random coupling hypothesis to explicitly demonstrate that (1) the major peak cluster spacing naturally arises from the unit in the copolymer with the widest distribution, as measured by the scaled standard deviation, (2) the spacing shift naturally occurs due to the marginal probabilities away from the spectrum maximum, and (3) the low molecular weight switch is a natural consequence of the tail of the distribution of the unit with the widest distribution. Results are provided to predict which unit in the copolymer will govern the major peak cluster spacing, how often the spacing will shift to that of another unit in the middle and high molecular weight regions of the spectrum, the molecular weight and composition of the maximum peak in every cluster, and the molecular weight below which the spacing will be that of the another unit. We believe that our results are the first to provide tangible theory to explain the previously unknown origins of these empirically observed phenomena.

show abstract

Section: Resultsmentioning

confidence: 99%

On the Origin of the Major Peak Cluster Spacing in the Mass Spectra of Copolymers

2013

View full text Add to dashboard Cite

show abstract

“…MALDI techniques have been applied for the analysis of co-polymers obtained from their monomer components or produced by reactive blending of polymers under controlled conditions. 3,[40][41][42][43][44][45][46][47][48] Mass spectra of co-polymers are significantly more complicated than those of homopolymers. A high mass resolution is necessary in order to detect the signals due to the individual oligomers in the co-polymer as separate peaks.…”

Section: Co-polymer Characterizationmentioning

confidence: 99%

“…1 The composition and microstructure of the low MM ethylene/carbon monoxide (E-CO) co-polymers were determined by MALDI-FT-ICR (ion cyclotron resonance) mass spectrometry, which gave high-resolution spectra and the isobaric E-CO oligomers could be fully resolved. 41 The chemical reduction of the CO units to a hydroxyl was also carried out to discriminate between the isobaric peaks with the same nominal mass of the E and CO units (i.e. 28 Da) but, unfortunately, the quantitative composition and microstructure measurements fail with MALDI-ToF MS analysis, due, probably, to its inability to ionize the oligomers fully.…”

Section: Co-polymer Characterizationmentioning

confidence: 99%

“…28 Da) but, unfortunately, the quantitative composition and microstructure measurements fail with MALDI-ToF MS analysis, due, probably, to its inability to ionize the oligomers fully. 41 In another work, the growth of the second block in a polystyrene-b-polyisoprene co-polymer was followed by MALDI analysis. 42 The average co-polymer compositions calculated from the MALDI spectra of the block co-polymers agreed with those obtained from 1 H-NMR spectra.…”

Section: Co-polymer Characterizationmentioning

confidence: 99%

See 1 more Smart Citation

Current Trends in Matrix-Assisted Laser Desorption/Ionization of Polymeric Materials

Montaudo

Samperi

Montaudo

et al. 2005

Eur J Mass Spectrom (Chichester)

View full text Add to dashboard Cite

In the last few years, mass spectrometry has rapidly become indispensable in polymer analysis and complements, in many ways, the structural data provided by nuclear magnetic resonance. Mass spectrometry of polymers is emerging as a revolutionary technique, capable of challenging the techniques and protocols established for years for the characterization of synthetic polymers. Matrix-assisted laser desorption/ionization (MALDI) has become a widely applied method for the structural characterization of synthetic polymers. The primary aim of this review is to illustrate some recent advances in the study of macromolecular systems by MALDI. MALDI allows the identification of repeat units and end groups, the structural analysis of linear and cyclic oligomers and the estimate of composition and sequence for co-polymers. MALDI is also quite useful for the measurement of molar mass and bivariate distributions in polymers and for the detection of self-association in macromolecules, performed by coupling MALDI with size exclusion chromatography (SEC). Recently MALDI has been applied, with remarkable success, to the study of thermal and oxidative processes in polymers and to the characterization of co-polymers obtained by reactive polymer blending. Selected applications of MALDI to polymers are illustrated herewith.

show abstract

“…Several applications of MALDI-FTICR-MS have been reported for the characterization of copolymers. [9][10][11][12] However, special skills for operation and careful maintenance of FTICR-MS are required, especially in the case of combination with a MALDI source.…”

Section: Introductionmentioning

confidence: 99%

Application of High-Resolution MALDI-TOFMS with a Spiral Ion Trajectory for the Structural Characterization of Free Radical Polymerized Methacrylate Ester Copolymers

et al. 2013

View full text Add to dashboard Cite

The structural characterization of copolymers by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) remains a challenging task, since their random comonomer distribution creates very complicated mass spectra. In this study, a high-resolution TOF mass spectrometer with a spiral ion trajectory was applied to the structural and compositional characterization of free radical copolymerized poly(methyl methacrylate-co-tert-butyl methacrylate), poly(MMA-co-tBMA)s in ethyl lactate acting as a chain transfer agent. Virtually complete peak assignments of the isobaric components within the poly(MMA-co-tBMA)s served to identify the end-group combinations and copolymer compositions of individual copolymer components, allowing the distributions of comonomer compositions and six types of end-group combinations to be evaluated.

show abstract

Microstructure and Composition of Ethylene−Carbon Monoxide Copolymers by Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

Cited by 10 publications

References 25 publications

On the Origin of the Major Peak Cluster Spacing in the Mass Spectra of Copolymers

On the Origin of the Major Peak Cluster Spacing in the Mass Spectra of Copolymers

Current Trends in Matrix-Assisted Laser Desorption/Ionization of Polymeric Materials

Application of High-Resolution MALDI-TOFMS with a Spiral Ion Trajectory for the Structural Characterization of Free Radical Polymerized Methacrylate Ester Copolymers

Contact Info

Product

Resources

About