Line broadening in the carbon-13 NMR spectra of crosslinked polymers

Bain, Alex D.; Eaton, D. R.; Hamielec, A. E.; Mlekuz, Michael.; Sayer, Brian G.

doi:10.1021/ma00199a011

Cited by 28 publications

(26 citation statements)

References 3 publications

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“…These assignments are consistent with those of the 13 C NMR studies of monocarboxylic esters of glycerol by Gunstone and Vlahov . The NMR spectra of the PGS gel shown in Figs (b) and (b) show considerable line broadening as expected of a crosslinked polymer, but the peak positions correspond to those of the pre‐polymer.…”

Section: Resultssupporting

confidence: 86%

Synthesis, characterization and properties of biocompatible poly(glycerol sebacate) pre‐polymer and gel

Li¹,

Cook

Moorhoff

et al. 2012

Polymer International

106

139

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Poly(glycerol sebacate) (PGS) is an elastomer with potential biomedical applications but it suffers from problems with irreproducible synthesis and the unacceptable toxicity of very soft PGS elastomers. To establish the reason for these problems, PGS was synthesized using different temperatures and reaction times, and the reaction was monitored by titration of the unreacted carboxylic groups and measurement of the mass loss during synthesis. It was found that evaporation of glycerol was a major cause of irreproducibility of the elastomer synthesis and this was more significant at higher reaction temperatures. The polymer microstructure was analysed using NMR spectroscopy and all twelve acylglyceride 13C‐signals as well as two small extra peaks of the residual glycerol were observed for the pre‐polymer. For the PGS gel, the glyceride moieties were characterized using NMR spectroscopy for the first time. The modulus and ultimate tensile strength of the gel increased with longer cure times and at higher cure temperatures while the elongation to break decreased and this was interpreted in terms of network theory. The cell viability of mouse fibroblasts was better for PGS samples with a higher conversion.© 2012 Society of Chemical Industry

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Section: Resultssupporting

confidence: 86%

Synthesis, characterization and properties of biocompatible poly(glycerol sebacate) pre‐polymer and gel

Li¹,

Cook

Moorhoff

et al. 2012

Polymer International

106

139

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“…It has been shown for polymer systems that the line width increase of a cured polymer system is due mainly to chemical-shift anisotropy and not to T 2 . 24 For the current work, the line widths change substantially, as was observed in an earlier 13 C-NMR cure study of the same compound. 1 It will be assumed that the major contributing factor to the increase in line width is chemicalshift anisotropy.…”

Section: Discussionsupporting

confidence: 64%

Study of the characterization and curing of a phenyl benzoxazine using15N solid-state nuclear magnetic resonance spectroscopy

Russell

Koenig

Low

et al. 1998

J. Appl. Polym. Sci.

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ABSTRACT:A difunctional 1,3-benzoxazine compound, 2,2Ј-(3-phenyl-4-dihydro-1,3,2-benzoxazine)propane (B-a), derived from bisphenol-A, 15 N-enriched aniline, and formaldehyde was synthesized and characterized using 15 N-NMR and 13 C-NMR spectroscopies. The observed resonances in the solid-state 15 N-and 13 C-NMR spectra showed good agreement with the calculated chemical shifts which are based on the chemical structure. The B-a samples were cured at 150 and 200°C. The polymerization inspired peak intensity changes and line-width broadenings in the NMR spectra.

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“…However, we analyzed the pure binder (without ceramic powder), which underwent a similar transformation curing in the oven. 20 The formation of cross-linked components products is in agreement with the theory of thermal degradation of hydrocarbons in the presence of oxygen. 8.…”

Section: Resultssupporting

confidence: 83%

Strength Evolution of Injection‐Molded Ceramic Parts During Wick‐Debinding

2011

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The mechanical properties of partially wick‐debinded, Al2O3‐based ceramic parts, prepared by low‐pressure injection molding have been investigated. These properties depend on the residual paraffin wax binder content and on the chemical nature of the binder, which changes drastically if the wick‐debinding takes place in air at a temperature above 190°C. Under these conditions, the paraffin binder undergoes a transformation, as a result of complex exothermic chemical reactions with oxygen. Part of it forms volatile products, while the remaining part cures into a nonvolatile, brown‐colored, solid substance, which resides in the wick‐debinded part and bonds the powder particles firmly together. The curing can be beneficial, as strong wick‐debinded parts with bending strengths up to 14 MPa, containing less than 2% of the residual binder, can be obtained without flaws. The strength of the partially debinded parts increases with the dwelling time at 200°C, whereas the binder content reaches a minimum value of about 1.6% and then remains constant with the dwell time. Strong debinded parts can be easily manipulated and can be rapidly sintered due to the low amount of the residual organic phase.

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Line broadening in the carbon-13 NMR spectra of crosslinked polymers

Cited by 28 publications

References 3 publications

Synthesis, characterization and properties of biocompatible poly(glycerol sebacate) pre‐polymer and gel

Synthesis, characterization and properties of biocompatible poly(glycerol sebacate) pre‐polymer and gel

Study of the characterization and curing of a phenyl benzoxazine using15N solid-state nuclear magnetic resonance spectroscopy

Strength Evolution of Injection‐Molded Ceramic Parts During Wick‐Debinding

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