Preparation And Properties Of Insulating Thermal Conductive Epoxy Resin Based Composites

The electrically insulating and thermally conductivity polymer composite are increasingly important for high reliability and long life for micro-electronic devices because it can remain good performance simultaneously in electrically insulating and thermally conductivity. On the basis of surveying of the relative literature about the electrically insulating and thermally conductivity polymer composite, three kinds of composites were prepared, using zinc oxide whisker(ZnOw), aluminum nitride(AlN) and their mixture as filler and epoxy resin(EP) as polymer matrix. The effects of fillers ,content, processing technology on the thermal conductivity, volume resistivity, dielectric property, coefficient of thermal expansion(CTE), thermal stability ,mechanical properties, structure and other properties of compsite were discussed detailedly by many modern analytical means, such as thermal conductive tester, high insulation resistance meters, scanning electron microscopy. The following conclusions can be obtained from the experiments:With addtion of AIN filler, thermal conductivity of the composite is promoted significantly. When the volume fraction of AIN was 30%, the thermal conductivity of composite came up to 0.72 W/ (m·K) , being more than four times of that of pure resin.The addition of AIN filler into epoxy resin decreases its volume resistivity whereas increases its dielectric constant and dielectric loss, however, it remains good electrically insulating properties. Meanwhile, the adhesive ability and thermal stability of composite were promoted with addtion of AIN filler, the coefficient of thermal expansion decreased.With addtion of a little ZnOw filler, thermal conductivity of the composite is promoted significantly.When the volume fraction of ZnOw was 10%, the thermal conductivity of composite came up to 0.68 W/ (m·K) , being nearly four times of that of pure resin.The addition of ZnOw into epoxy resin decreases its volume resistivity whereas increases its dielectric constant and dielectric loss, however, it remains good electrically insulating properties. the tensile strength of the composite at first increased and then decreased, it indicated that a small quantity of whisker could reinforce the composite. Meanwhile, the adhesive ability and thermal stability of composite were promoted, the coefficient of thermal expansion was decreased.The use of hybrid ZnO wisker and AIN particles provides composite with better thermal conductivity than the role paticles used . Comparing some typical equation with experimental data of filled thermal conductive composites, Maxwell's equation was adaptable for AIN/EP composite; and Agari.Y's equation was adaptable for AIN/EP composite.