Accepted for publication in – Materials Science Forum – Published in November 12, 2012 DOI: 10.4028/www.scientific.net/MSF.729.80 Development of thermally conductive polymer materials and their investigation András SUPLICZ 1, a , József Gábor KOVÁCS 1, b 1 Department of Polymer Engineering, Budapest University of Technology and Economics, Budapest H-1111, Hungary a suplicz@pt.bme.hu, b kovacs@pt.bme.hu Keywords: thermal conductivity, low melting point alloy, injection molding, hot-plate method Abstract. In the recent years a remarkable development can be observed in the electronics. New products of electronic industry generate more and more heat. To dissipate this heat, thermally conductive polymers offer new possibilities. The goal of this work was to develop a novel polymer based material, which has a good thermal conduction. The main purpose during the development was that this material can be processed easily with injection molding. To eliminate the weaknesses of the traditional conductive composites low-melting-point alloy was applied as filler. Furthermore in this work the effect of the filler content on thermal conductivity, on structure and on mechanical properties was investigated. Introduction Recently the developments in technology result smaller devices with higher performance. Thanks to this advance the heat dissipation in the electronic packaging, mainly in the microelectronics is an important issue. Beside this the heat dissipation has a great influence on the lifespan. It is well known that the reliability of devices is exponentially dependent on its operating temperature, so a small difference in operating temperatures (about 10–15°C) can halve the lifespan of the devices [1-5]. It is well known that the polymer materials are good thermal insulators as their thermal conductivity varies between 0.1 and 0.5 W/(m∙K). Generally conductive polymer composites are obtained dispersing conductive fillers into insulating polymer matrix. These fillers are mainly graphite, carbon black, and carbon fibers, ceramic or metal particles. They can increase the thermal behavior of polymers significantly. Furthermore the thermal properties depend on several factors: the filler concentration, the ratio between the properties of the components, the size and the shape of the filler particles, the manufacturing process and the filler matrix interactions. Nowadays the polymer based composite materials which have high thermal conductivity attract more and more attentions. Interest in using polymers for other electrical applications has increased due to their advantageous properties such as resistance to chemicals, weight and processability. Thermally conductive polymer composites offer new possibilities for replacing metal parts in several applications, such as electric motors, power electronics, heat exchangers, microelectronics, and many others [4, 5]. The thermal properties of thermoplastic polymers filled with metal or ceramic particles were investigated by different researchers [6-10]. It is important, that compromises have to be found regarding the amount of filler. Higher filler contents usually have a negative influence on the mechanical properties and also on processability due to the increase of melt viscosity. Many