Transient plane source method

In this section, the differences between using CVD hybrid fillers and physically mixed hybrid fillers in polymer composites were studied. It shows an interesting result with regard to the thermal and hardness properties of composites. The synergistic effects of two components in the hybrid fillers helped each other perform as fillers and reinforcements in polymer composites. The thermal conductivities and hardnesses of phenolic/CNT—alumina hybrid composites were studied. The CNT—alumina hybrid (HYB compound) was produced via the CVD method, which was discussed in Section 5.6. The phenolic/CNT—alumina hybrid composites were fabricated using hot-mounted molding. Thermal conductivity was measured using the transient plane source method with a Hot-Disk Thermal Constant Analyzer. Table 5.4 shows the sample description in this study. 

A comparison of guarded hot plate, transient plane source and modified hot wire methods has been made54 using polyurethane foam, and the strengths and weaknesses of the techniques discussed,... 

TPS (Transient Plane Source) technique has been shown to be effective method to measure the thermal conductivity, diffusivity of rare earth oxide powder such as gadolinium oxide, samarium oxide, and yttrium oxide. The details of the measutrement are described in Ref 66. The experimental results of effective thermal conductivity as well as thermal diffusivity of the above described three rare earth oxides are tabulated in Table 5-7. 

Various other methods have been described for the determination of thermal conductivity. Capillarity has been used to measure the thermal conductivity of LDPE, HOPE and PP at various temperatures and pressures [30]. A transient plane source technique has been applied in a study of the dependence of the effective thermal conductivity and thermal diffusivity of polymer composites [31]. 

Transient Plane Source Thermal Conductivity Test Method... 

The Mathis Instruments Hot Disk Thermal Constants Analyzer is an emerging technology that can measme the in-plane and through-plane TC of an anisotropic material in the same test, using the transient plane source technique [13-17]. The saisor used in this test method is a 10 micron thick nickel foil embedded between two 25.4 micron thick layas of Kapton polyimide film. The nickel foil is wound in a double spir pattern with a radius of 3.189 mm. The thomal eonductivities were measmed at 23"C. 

The time-dependent temperature distribution in a transient experiment is governed by Eq. 4, and usually the related parameter, thermal diffusivity. is obtained. However, under certain circumstanees the solution to the heat equation contains the thermal conductivity as well as the thermal diffusivity, and by choosing a suitable method the diffusivity can be eliminated from the answer. The more important methods are the line and plane source heater methods and arc described below. These arc not Standard methods, but they can be used where speed is more imp .>rtant than absolute accuracy, to give a conductivity value more quickly than the Standard methods. They can also be used to compare a range of materials. 

Transient-state or unsteady-state methods make nse of either a line source of heat or plane sources of heat. In both cases, the usual procedure is to apply a steady heat flux to the specimen, which mnst be initially in thermal eqnUibrinm, and to measnre the tanperatnre rise at some point in the specimen, resnlting from this applied flux [83]. The Fitch method is one of the most common transient methods for measuring the thermal conductivity of poor conductors. This method was developed in 1935 and was described in the National Bureau of Standards Research Report No. 561. Experimental apparatus is commercially available. 

ISO 22007-2 2015. Plastics — Determination of thermal conductivity and thermal diffu-sivity — Part 2 Transient plane heat source (hot disc) method. 

Transient-state or unsteady-state methods make use of either a line source of heat or plane sources of heat. 

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