Measuring Anisotropic or Oriented Samples by Modified Transient Plane Source (MTPS) Technique
C-Therm’s TCi thermal conductivity measurement is based on the modified transient plane source (MTPS) technique. The MTPS method provides a fast, highly-accurate, and easy way to measure the thermal conductivity of both isotropic and anisotropic samples. For this reason it has become a very popular tool for rapid quality control in the manufacturing of conductive polymers with oriented glass fibres and other fillers for improved heat transport.
With C-Therm's patented one-sided sensor, clients enjoy the added benefit of not having to mock up specific samples for thermal conductivity testing. The only requirement is to cover the active 18-mm diameter surface area of the sensor. The figure below illustrates the testing of tensile bars. The bars were described as a polymer resin with carbon fibres heavily oriented in the in-plane direction, and were already produced for testing the tensile strength of the material. The grip section provided sufficient contact area for the through-plane thermal conductivity measurement. The limited 4mm thickness of the bars required multiple samples to be clamped together for the in-plane measurement. In being able to use tensile bars for testing both the through-plane and in-plane thermal conductivity, this saves the client time and money in ensuring the product is meeting the critical performance attributes for heat transport.