NMR‐Messmethoden

Schuhmann, Sebastian; Guthausen, Gisela

doi:10.1002/ciuz.202000009

Cited by 2 publications

(4 citation statements)

References 51 publications

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“…The sensitivity towards aging was already demonstrated for classic LF NMR (spectroscopy and relaxation). [ 34 ] The magnetization decays measured with the sensor (Figure 7a) show the expected behavior: The decays are a function of t run , which becomes unambiguously evident for t run = 61 h. They were analyzed in terms of the bimodal gamma model (Figure 7b).…”

Section: Application To the Study Of Lubricantsmentioning

confidence: 82%

“…The lower limit of detection thus is higher compared with previous, classic relaxation measurements. [ 34 ] The provoked gear failure, however, is clearly identified: Both 〈 R 2,eff,CH2 〉 and 〈 R 2,eff, CH3 〉 show a steep increase and can be used as an indicator. The on‐site application of the sensor would thus enable the operator to respond to the oil aging in time and to initiate countermeasures in time such as an oil change or replacement of gear components.…”

Section: Application To the Study Of Lubricantsmentioning

confidence: 99%

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Dedicated NMR sensor to analyze relaxation and diffusion in liquids and its application to characterize lubricants

Rudszuck¹,

Zick

Gross

et al. 2021

Magnetic Reson in Chemistry

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A dedicated nuclear magnetic resonance (NMR) sensor was designed for the analysis of liquids. The magnets are arranged in a V shape, creating a spatially dependent magnetic field in the gap. Measurements of samples with diverse diameters are possible underdefined magnetic field gradients at a given position. The magnet thus combines properties of single sided NMR with high static magnetic field gradients and classical time domain (TD) devices with lower to almost zero gradients. The sensor can easily be adapted to the requirements of the considered investigation; probes can be customized. On the example of lubricants and their aging, the added value and applicability of this sensor in quality control are highlighted in this publication. Relaxation and diffusion were measured by Carr–Purcell–Meiboom–Gill (CPMG) while varying the echo time τe and quantified via numerical modeling. Especially, relaxation shows a high sensitivity towards aging of lubricants such as particulate abrasion and changes in molecular dynamics induced, for example, by additive depletion. The applicability of this NMR sensor in quality control is demonstrated on the example of engine and transmission oils as well as of lubrication greases.

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Section: Application To the Study Of Lubricantsmentioning

confidence: 82%

Section: Application To the Study Of Lubricantsmentioning

confidence: 99%

Dedicated NMR sensor to analyze relaxation and diffusion in liquids and its application to characterize lubricants

Rudszuck¹,

Zick

Gross

et al. 2021

Magnetic Reson in Chemistry

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“…Diffusion coefficients for the cation and anion were obtained by 1 H-NMR (cation) and 19 F-NMR (anion) using a pulsed-field gradient stimulated echo (PFG-STE) sequence at different temperatures. Diffusion coefficients were calculated using the Stejskal-Tanner equation [29,41,42] by measuring the ratio S/S 0 as follows:…”

Section: Pulsed-field Gradient Nuclear Magnetic Resonance (Pfg-nmr)mentioning

confidence: 99%

“…Furthermore, the mobility of the ions was investigated by pulsed-field gradient nuclear magnetic resonance spectroscopy (PFG-NMR) [29]. PFG-NMR allows for the determination of the translational dynamics and diffusion coefficients of moieties [30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Charge Transport and Glassy Dynamics in Blends Based on 1-Butyl-3-vinylbenzylimidazolium Bis(trifluoromethanesulfonyl)imide Ionic Liquid and the Corresponding Polymer

et al. 2022

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Charge transport, diffusion properties, and glassy dynamics of blends of imidazolium-based ionic liquid (IL) and the corresponding polymer (polyIL) were examined by Pulsed-Field-Gradient Nuclear Magnetic Resonance (PFG-NMR) and rheology coupled with broadband dielectric spectroscopy (rheo-BDS). We found that the mechanical storage modulus (G′) increases with an increasing amount of polyIL and G′ is a factor of 10,000 higher for the polyIL compared to the monomer (GIL′= 7.5 Pa at 100 rad s−1 and 298 K). Furthermore, the ionic conductivity (σ0) of the IL is a factor 1000 higher than its value for the polymerized monomer with 3.4×10−4 S cm−1 at 298 K. Additionally, we found the Haven Ratio (HR) obtained through PFG-NMR and BDS measurements to be constant around a value of 1.4 for the IL and blends with 30 wt% and 70 wt% polyIL. These results show that blending of the components does not have a strong impact on the charge transport compared to the charge transport in the pure IL at room temperature, but blending results in substantial modifications of the mechanical properties. Furthermore, it is highlighted that the increase in σ0 might be attributed to the addition of a more mobile phase, which also possibly reduces ion-ion correlations in the polyIL.

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NMR‐Messmethoden

Cited by 2 publications

References 51 publications

Dedicated NMR sensor to analyze relaxation and diffusion in liquids and its application to characterize lubricants

Dedicated NMR sensor to analyze relaxation and diffusion in liquids and its application to characterize lubricants

Charge Transport and Glassy Dynamics in Blends Based on 1-Butyl-3-vinylbenzylimidazolium Bis(trifluoromethanesulfonyl)imide Ionic Liquid and the Corresponding Polymer

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