Molecular dynamics of elastomers investigated by DMTA and the NMR-MOUSE ®

Herrmann, Volker; Unseld, K.; Fuchs, H. B.; Blümich, Bernhard

doi:10.1007/s00396-002-0688-x

Cited by 25 publications

(22 citation statements)

References 4 publications

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“…Simultaneously, the measured T 2 value decreases after the sample has been exposed to UV irradiation. Crosslinking is associated with reduced T 2 values, as reported elsewhere [15]. The top surface, exposed to the most intense UV irradiation, is more completely cured and shows greater crosslinking (smaller T2 values).…”

Section: Resultsmentioning

confidence: 65%

“…Simultaneously, the measured T2 value decreases after the sample has been exposed to UV irradiation. Crosslinking is associated with reduced T2 values, as reported elsewhere [15]. .…”

Section: Resultsmentioning

confidence: 90%

“…This method of data presentation highlights spatial variations in relaxation times and is used throughout this report. relaxation rates that, when added, best represent the overall signal attenuation in the signal: smaller T2 relaxation times (to the left of the ILT spectrum) indicate greater relaxation which, in turn, suggests more crosslinking [15]. The final product of this data processing approach is a relaxation cross-section (position, z, vs. T2) that shows differences in local crosslinking at different depths in the sample.…”

Section: Resultsmentioning

confidence: 99%

“…Once every echo has been transformed into the spatial domain, the signal decay (over the many successive echoes) at each position is subjected to an inverse Laplace transformation (ILT), the result of which is a relaxation "spectrum" at each position. An ILT produces a spectrum showing the intensity of various relaxation rates that, when added, best represent the overall signal attenuation in the signal: smaller T 2 relaxation times (to the left of the ILT spectrum) indicate greater relaxation which, in turn, suggests more crosslinking [15]. The final product of this data processing approach is a relaxation cross-section (position, z, vs. T 2 ) that shows differences in local crosslinking at different depths in the sample.…”

Section: Resultsmentioning

confidence: 99%

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Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

2018

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Abstract:The UV-driven photocuring of coatings results in a crosslinked polymeric network. The degree of crosslinking in these coatings is typically assessed via optical spectroscopy; unfortunately, optical methods are typically limited in their maximum depth access. Alternatively, single-sided nuclear magnetic resonance (NMR) can be used to probe the crosslinking of UV-curable coatings in a spatially sensitive manner. Relaxation measurements, which correlate with crosslinking, can be done with a spatial resolution on the order of microns throughout the depth dimension of the coating, regardless of optical transparency of the material. These results can be visualized via a relaxation cross-section that shows the depth at which a particular relaxation value is observed. These measurements are used to probe the effect of a scavenger molecule that is added to the coating mixture, allowing for efficient crosslinking despite the presence of atmospheric oxygen. This method may find purchase in evaluating systems whose crosslinking properties are intentionally varied throughout its thickness; using NMR, these systems, up to approximately one hundred microns thick, can be measured without repositioning or rastering.

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Section: Resultsmentioning

confidence: 65%

“…Simultaneously, the measured T2 value decreases after the sample has been exposed to UV irradiation. Crosslinking is associated with reduced T2 values, as reported elsewhere [15]. .…”

Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

2018

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“…[5][6][7][8] While the obvious challenge is to achieve large penetration depths and homogeneous fields, the challenge of maximizing the sensitivity for thin samples seems to have been neglected. Membranes, paper, coatings, and surface layers from polymer aging and degradation are examples of thin objects of technical interest for analysis by NMR.…”

Section: Introductionmentioning

confidence: 99%

An NMR‐MOUSE® for Analysis of Thin Objects

Blümich

Anferov

Anferova

et al. 2003

Macro Materials & Eng

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A special unilateral NMR sensor has been designed for investigations of thin samples with a thickness of less than 1 mm and of surface effects of polymers. For use with the bar‐magnet NMR‐MOUSE®, the so‐called “crazy coil” is introduced with a low penetration depth. It is a flat meander coil etched on a printed circuit board with wiggles in the conductors. The design of the new coil and FEM simulations of the B1 field are presented. Different applications are discussed by means of illustrative examples. They are the detection of surface damage in rubber samples, the swelling and drying of a latex membrane exposed to cyclohexane vapor mimicking a chemical sensor, and the drying of a thin sprayed adhesive layer.

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Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform ¹H NMR Relaxometry and Rheometry

Moldovan

Fechete

Demco

et al. 2010

Macro Chemistry & Physics

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The heterogeneous effects due to filler interactions and chain dynamics of reinforcing nano‐filler particles were characterized on a series of filled EPDM elastomers using the Payne effect and low field NMR, 1H transverse (T2), longitudinal (T1) and longitudinal in rotating frame (T1ρ) relaxation time measurements. Measurement of the Payne effect and NMR relaxation curves were used to obtain the distribution of filler/filler interactions and chain dynamics by one‐dimensional Laplace inversion. Distributions of shear‐strain constants in the Payne effect reveal the existence of weak, medium and strong filler/filler interactions which were correlated to filler properties and content. The analysis of relaxation‐time distributions leads to the identification of multimodal polymer network dynamics.magnified image

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Molecular dynamics of elastomers investigated by DMTA and the NMR-MOUSE ®

Cited by 25 publications

References 4 publications

Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

An NMR‐MOUSE® for Analysis of Thin Objects

Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform ¹H NMR Relaxometry and Rheometry

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Molecular dynamics of elastomers investigated by DMTA and the NMR-MOUSE ®

Cited by 25 publications

References 4 publications

Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

Spatially Resolved Measurements of Crosslinking in UV-Curable Coatings Using Single-Sided NMR

An NMR‐MOUSE® for Analysis of Thin Objects

Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform 1H NMR Relaxometry and Rheometry

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Heterogeneity of Nanofilled EPDM Elastomers Investigated by Inverse Laplace Transform ¹H NMR Relaxometry and Rheometry