Thermal Conductivity Testing Methods Using Industrial Rubbers/Rubber Compounds

Now a days, in every polymer industries, the simulations of injection molding is very important to increase the production of industrial rubber compounds and also to reduce the optimization cycles in mold making. While doing the simulations, thermal conductivity measurement as a function of temperature is very crucial property to know the temperature distribution and degree of crosslinking. Generally rubber compounds are having low thermal conductivity around 0.15–0.4 W M−1 K−1and the molding of rubber part is taking place through crosslinking reaction. So total cycle time is high (in the range of minutes). So optimization of this lengthy process is required. Thermal conductivity of rubber compounds can be determined by a stationary (Guarded Heat Flow Meter (GHF)), and three transient methods (Plane-Source (TPS), Line-Source (TLS), and Laser Flash Analysis (LFA)). If we use fillers for the rubber compounds, it show anisotropic material Behavior. Thermal conductivity of a rubber compound, measured by TPS method is lower than other methods due to the diffusion of volatile substances on the surface and the orientation of fillers in the compound. The results from TLS and GHF method matches each other. Though the rubber compounds with no crosslinking can only be applicable for TLS method. Hence GHF and LFA methods provide very precise data regarding the thermal conductivity of rubber compounds.