Dynamic mechanical analysis with portable NMR.

Area of Science:

• Materials Science
• Rheology
• Physics

Background:

• Dynamic mechanical analysis (DMA) is crucial for characterizing material properties under oscillatory stress.
• Traditional DMA methods can be complex and require specialized equipment.
• Measuring sample velocity directly offers a new approach to DMA.

Purpose of the Study:

• To present a new method for DMA using a magnetic array to measure sample velocity.
• To demonstrate how velocity waveforms can characterize dynamic mechanical properties.
• To determine the dynamic modulus and loss-angle of materials.

Main Methods:

• Utilized a small unilateral three-magnet array with an extended constant gradient.
• Oriented sample vibrations along the magnetic gradient direction.
• Employed motion-sensitized phase accumulation and pulse sequence delays to acquire velocity waveforms.

Main Results:

• Successfully measured the velocity of a vibrating sample.
• Acquired complete velocity waveforms by measuring phase at evenly spaced points.
• Demonstrated that amplitude and phase differences in waveforms correlate with dynamic modulus and loss-angle.

Conclusions:

• The presented magnetic array method provides a novel approach to dynamic mechanical analysis.
• Velocity waveform analysis enables accurate determination of key material dynamic properties.
• This technique offers a potentially simpler and more direct method for DMA.