C-Therm Blog

Measuring the Thermal Conductivity of Anisotropic Materials

Anisotropy refers to the directional dependency of a material.  In material development, polymers are often engineered to have heat flow patterns that are anisotropic (directionally depedent). This is accomplished with polymers formulated with glass fibres, graphite and other conductive fillers such as boron nitride or silver.   Increasingly, carbon nanotubes are also being used to improve the thermal conductivity.   C-Therm's TCi thermal conductivity analyzer employs the Modified Transient Plane Source (MTPS) which was originally developed by Dr. Nancy Mathis at the University of New Brunswick specifically for testing  the homogeneity and anisotropic heat transfer properties of polymer materials.

The technology has come a long way in the 20 years since this early work - but the principles involved remain the same.

Chart 1:  Thermal Conductivity Measurement of Carbon Fiber Weave Polymer Composite

Anisotropic Thermal Conductivity Measurement
Sample Orientation Thermal Conductivity (W/mK) RSD (%, N=15)
In-Plane 119.2 0.5
Through-Plane 2.01 0.6

For more information on how the C-Therm TCi can be used to test the thermal conductivity of your anisotropic materials contact us.

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