chemical shift thermometer at high temperature for magic angle spinning experiments

Takahashi, Takehiro; Kawashima, Hiroe; Sugisawa, Hisashi; Baba, Toshihide

doi:10.1016/s0926-2040(99)00039-9

Cited by 121 publications

(93 citation statements)

References 14 publications

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“…A typical 901 pulse length was 4 ms and typical delays for 7 Li 10 s, for 6 Li 120-300 s, for 29 Si 10 s. Dry nitrogen gas was used for MAS experiments with typical spinning speeds of 10 kHz for room temperature and 5-8 kHz for lowtemperature MAS. Temperatures were calibrated using the 207 Pb resonance of lead nitrate as previously described [20,21]. Deconvolution of the spectra was done using the DMfit software [22].…”

Section: Solid State Nmrmentioning

confidence: 99%

Structural and dynamic characterization of Li12Si7 and Li12Ge7 using solid state NMR

Dupke

Langer

Pöttgen

et al. 2012

Solid State Nuclear Magnetic Resonance

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Section: Solid State Nmrmentioning

confidence: 99%

Structural and dynamic characterization of Li12Si7 and Li12Ge7 using solid state NMR

Dupke

Langer

Pöttgen

et al. 2012

Solid State Nuclear Magnetic Resonance

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“…The actual temperature at which the sample was kept was calibrated mainly by the classical methanol method under MAS, 3 and the lead nitrate method 4 was partly used to estimate the actual temperature. Anhydrous methanol was sealed in a rotor with an o-ring cap for a 6.0-mmf sample rotor.…”

Section: Nuclear Magnetic Resonance Measurementsmentioning

confidence: 99%

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Asano

Hori

Kitamura

et al. 2012

Polym J

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We have investigated the influence of the high centrifugal pressure caused by fast magic-angle spinning (MAS) on the molecular motion of styrene-butadiene rubbers (SBR) filled with SiO 2 (SBR/Si composite) though solid-state magic-angle spinning nuclear magnetic Resonance ( 1 H MAS NMR) measurements. Because the 1 H-1 H dipolar interaction of elastomers is weak compared with that of glassy polymers, a narrower 1 H linewidth is observed under fast MAS. The temperature dependence of the 1 H spin-lattice relaxation time (T 1 H ) revealed that the T 1 H minimum increases with the MAS rate. Furthermore, we observed a difference in the temperature dependence of T 1 H between end-chain-modified SBR and normal (unmodified) SBR in the SBR/Si composites. The temperature dependence of T 1 H is described by the Bloembergen-Purcell-Pound theory, with the assumption that the correlation time obeys the Williams-Landel-Ferry empirical theory. The fitting showed that the molecular motion does not change significantly until a MAS rate of 20 kHz, with the motional mode changing considerably at a MAS rate of 25 kHz. The motion of SBR in the unmodified SBR/Si composite was greatly affected by the fast MAS rates. Furthermore, the plot of the estimated centrifugal pressure versus the T 1 H minimum resembled the stress-strain curve. This result enables the detection of macroscopic physical deformation by the microscopic parameter INTRODUCTIONSolid-state NMR is useful for the investigation of the molecular motion of the functional groups of elastomers and polymers. In particular, the recent development of the magic-angle spinning (MAS) technique allows a sample rotor to be spun much faster than 20 kHz. Thus, we can detect the high-resolution 1 H signals of rubbers and elastomers under the fast rates that are possible in MAS because these fast MAS rates effectively reduce the signal broadening that arises from the relatively weak 1 H-1 H dipolar interaction of elastomers (in comparison with that of glassy solid polymers).Generally, spin-lattice relaxation time (T 1 ) is observed to study molecular motion. In the case of rare spins such as 13 C, however, it is time-consuming to observe the signals and measure an accurate T 1 with a good signal-to-noise ratio. In contrast, proton signals are intense enough to allow quick analysis of molecular motion through the T 1 measurement. However, for a glassy solid polymer, the strong 1 H-1 H dipolar interaction obscures the individual functional group signals, even with fast MAS. For rubbers and elastomers under fast MAS, in contrast, each peak assigned to a respective functional group can be detected because of the weak 1 H-1 H dipolar interaction. Furthermore, it is easy to detect 1 H-T 1 ( 1 H spin-lattice relaxation time (T 1 H )) accurately. In contrast, it is well known that MAS causes the temperature of the inner sample to increase because of friction between the MAS and the air. In addition, it has recently been reported that fast MAS causes

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“…The temperature of the sample placed in a rotor is usually determined using a temperature dependence of the isotropic chemical shift, the width of resonance lines as well as the changes of chemical shift anisotropy parameters (at low MAS rates) of various calibration materials [1][2][3][4][5][6][7][8][9][10][11][12]. These procedures have been applied for Bruker, Jeol, and General Electric spectrometers.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Sample Temperatures and Temperature Gradients in Magic-Angle Spinning Nmr

Hronský¹

2013

Acta Electrotechnica Et Informatica

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chemical shift thermometer at high temperature for magic angle spinning experiments

Cited by 121 publications

References 14 publications

Structural and dynamic characterization of Li12Si7 and Li12Ge7 using solid state NMR

Structural and dynamic characterization of Li12Si7 and Li12Ge7 using solid state NMR

Influence of magic angle spinning on T1H of SBR studied by solid state 1H NMR

Measurement of Sample Temperatures and Temperature Gradients in Magic-Angle Spinning Nmr

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