Composite material systems composed of a matrix of nanomaterials can achieve combinations of mechanical and thermophysical properties outside the range of traditional systems. The microstructure of the system dictates the rate, in which heat moves through the material. In this work, air/carbon nanofiber networks are studied to elucidate the system parameters influencing thermal transport. Thermal properties are measured with varying initial carbon fiber fill fraction, environment pressure, loading pressure, and heat treatment temperature (HTT) through a bidirectional modification of the 3ω technique. The nanostructure of the individual fibers is characterized with small angle X-ray scattering and Raman spectroscopy providing insight to individual fiber thermal conductivity. Measured thermal conductivity of the carbon nanofiber networks varied from 0.010 W/(m K) to 0.070 W/(m K). An understanding of the intrinsic properties of the individual fibers and the interactions of the two-phase composite is used to reconcile low measured thermal conductivities with predictive modeling. Accounting for fiber-to-fiber interactions and the nuanced changes in the composite as pressure is applied is necessary to successfully model thermal transport in system.
Thermal Conductivity of Turbostratic Carbon Nanofiber Networks
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
University of New Mexico,
Albuquerque, NM 87131
Albuquerque, NM 87185
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
University of New Mexico,
Albuquerque, NM 87131
Albuquerque, NM 87185
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Aerospace Engineering,
University of Virginia,
Charlottesville, VA 22904-4746
Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received April 8, 2015; final manuscript received November 27, 2015; published online March 15, 2016. Assoc. Editor: Alan McGaughey.The United States Government retains, and by accepting the article for publication, the publisher acknowledges that the United States Government retains, a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for United States government purposes.
Bauer, M. L., Saltonstall, C. B., Leseman, Z. C., Beechem, T. E., Hopkins, P. E., and Norris, P. M. (March 15, 2016). "Thermal Conductivity of Turbostratic Carbon Nanofiber Networks." ASME. J. Heat Transfer. June 2016; 138(6): 061302. https://doi.org/10.1115/1.4032610
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