A Study on Thermal Behaviour of Carbon Black Filled Epoxy Composites

Abstract

This thesis gives a report on numerical and the experimental studying of the thermal and well as the physical behaviour of the singe filler - polymer composite. The primary objective is set to use carbon black particulates which are extracted from waste tyres trough pyrolysis process to enhance the thermal properties of the epoxy polymer so as to make it suited to be used in micro- electronic usages. The steps of pyrolysis are been discussed in details along with the waste tyres properties out of which the carbon black particulates are been made. In the initial part we have calculated the thermal conductivity based on the numerical analysis, this is compared to the result obtained by the analytical equations . In secondary step the discussion is concentrated on the details of experimental procedure, material and there properties especially the physical, thermal and microstructural properties. The properties analysed are density, surface texture, effective Thermal conductivity (Keff), Glass transition temperature (Tg ) , Coefficient of thermal expansion (CTE). The Keff of the composite is enhanced if volume percent of high thermally conductive material is increased, this creates a low thermal resisting bridges inside the composite which facilitates the enhanced heat flow through it. The percolation phenomenon is described as the process when high conductive filler are added, and at a point when the volume percentage is sufficiently high than they form a highly conductive bridges, hence increasing the overall thermal conductivity of the composite. By this phenomenon the thermal conductivity keep on increasing as we increase the carbon black content but there exist a specific fractional volume of the filler for which there is a instantaneous rise in the thermal conductivity, and this is called the percolation threshold of the filler matrix.
For the numerical analysis to calculate the thermal conductivity of the composite the Finite Element Method is employed. The Keff of the reinforced particulate composite is evaluated by using the CFD (FINITE ELEMENT PACKAGE) ANSYS 15 MECHANICAL APDL. Various cases have been formulated, which emphasises on the variation of the carbon black volume and the effective thermal conductivity is calculated for each cases.