Carbon black: a thermally conductive reinforcement for epoxy based composite

Heat conduction plays a vital role in the performance and durability of any component. A wide range of applications are available that demand a good heat conduction ability. The property used to understand the heat conduction behaviour in a solid is called effective thermal conductivity (K_eff). It is recommended to reinforce an adequate amount of filler material in the matrix to increase the K_eff of the composite. The current study used carbon black (CB) particulates, a by-product of waste tyre pyrolysis, as the reinforcing agent in the epoxy resin. The composites are prepared by solution casting method with different volume % of filler. To study the thermal behaviour of samples, effective thermal conductivity, glass transition temperature (T_g) and co-efficient thermal expansion (CTE) are measured as a function of vol.% of filler. After plotting the experimental results, it is noticed that the K_eff and T_g are increased and CTE is decreased with an increase in vol.% of CB. The percolation threshold is also calculated from the K_eff vs. vol.% curve. Various mathematical models are incorporated to verify the experimental results of effective thermal conductivity. A finite element method (FEM) based numerical model is also developed to study the thermal conductivity behaviour of composites. ANSYS MECHANICIAL APDL is used for the FEM analysis. The FEM results showed a marginal variation from experimental data at 0.99 vol.% of CB. The reason behind this is the formation of voids during sample making, the effect of which is not taken in FEM.