Effect of Probe Diameter on the Thermal Conductivity of Molten Polymers Measured Using Twin Probe.

SATO Sadao, HAYASHI Yuki, KANESATO Hiroaki

doi:10.1295/koron.58.9

In thermal conductivity measurements determined using a probe, there have been no papers that have examined the effects of the probe diameter on the thermal conductivity of molten polymers. The purpose of this study is to investigate the performance of probes with different diameters in order to clarify this effect, to discuss the temperature dependence and accuracy of thermal conductivity measurements, and to determine the optimum relationship between sample diameter D and probe diameter d. The thermal conductivity of a number of polymers is estimated for a probe diameter that approaches 1 mm at 50, 100 and 200°C. From these results the following conclusions are drawn: The temperature dependence of the thermal conductivity of polypropylene (PP) and polystyrene (PS) increases with increasing temperature. The thermal conductivites of molten PP and PS are observed to be constant or to gently increase with increasing temperature, although they exhibit a dip at the melting and glass transition points. In addition, the thermal conductivity of molten polymer is found to decrease with decreasing probe diameter, and measurement accuracy can be improved from ±12.2% to ±7.3%. The estimated thermal conductivity of PP and PS in the case when a probe diameter of was used 1 mm are 0.12 W/m·°C and 0.10 W/m·°C, respectively. The optimal specimen diameter D for a given probe diameter d is D>9d.

Effect of Probe Diameter on the Thermal Conductivity of Molten Polymers Measured Using Twin Probe.

Bibliographic Information

Abstract

Journal

Keywords

Details 詳細情報について

Export

Report a problem