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An Absolute Determination of Viscosity Using a Torsional Pendulum
Hobart S White1, Elliot A Kearsley1
1Institute for Basic Standards, National Bureau of Standards, Washington, D.C. 20234.
Summary
This study precisely measured the viscosity of di(2-ethylhexyl) sebacate using a torsional pendulum viscometer. Results showed high accuracy, though a small discrepancy with capillary viscometer data remains unexplained.
Area of Science:
- Physical Chemistry
- Materials Science
Background:
- Viscosity is a critical property for lubricants and plasticizers.
- Accurate viscosity measurements are essential for material characterization and quality control.
Purpose of the Study:
- To perform an absolute viscosity measurement of di(2-ethylhexyl) sebacate.
- To detail the apparatus, calibration, and error analysis for torsional pendulum viscometry.
Main Methods:
- Utilized a torsional pendulum viscometer for absolute viscosity determination.
- Conducted thorough calibration and error analysis of the experimental setup.
Main Results:
- Achieved a systematic error of less than ±0.07% and variability below ±0.07%.
- Observed an unexplained difference of 0.3-0.4% compared to capillary viscometer measurements.
Conclusions:
- The torsional pendulum viscometer provides highly accurate and reproducible viscosity measurements.
- Further investigation is needed to reconcile the observed discrepancy with capillary viscometry data.
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