The Study On Thermal Conductive Rubber And Plastic Polymeric Materials

With the development of technology and science, traditional thermal conductive materials -metals have been limited in special fields, for erosion and electric conductivity. Such as heat exchanger used in chemical engineering and waste water disposal, require not only highly thermal conductivity but also resistant to chemical erosion and high temperature. And in the fields of electron and electric, with the development of integration and assembly technique, the electronic components and logic circuit have much quantity of heat for its miniaturization and micromation. All of this needs highly thermal conductive and insulated materials to dissipate it. Polymer materials which have highly thermal conductivity and insulation meet it. Therefore, the study on thermally conductive polymer materials become very important.In this paper, by means of steady state method, a simple equipment used in measuring the thermal conductivity was designed. The equipment has its characteristics of being convenient and rapid. And a new method on measuring thermal conductivity based on this simple equipment was devised. Comparing with the advanced apparatus of measuring thermal conductivity, this equipment has its error less than 10%, which could satisfy the need of experiments. Furthermore, the reason of error and how to eliminate are discussed.Based on the new equipment and method, the thermal conductive performance, mechanical performance and electric performance of HDPE/thermal filler composites, silicon rubber/thermal filler composites are researched. With the increasing of thermal filler content, the mechanical performances of HDPE, silicone rubber have the trend of decreasing, while the thermal conductivities of them have the trend of increasing, and a sharp increase occurs, which filled with single filler. With the fillers content limited, the proportion of two kinds of fillers changing would have effect on the thermally conductive performance, mechanical performance and electric performance of HDPE and silicone rubber.Furthermore, the internal thermal conductive mechanism of polymer materials is discussed. The kind of filler, the content of filler and the diameter of filler which have effect on thermal conductivity of plastic and rubber are analysed. At the same time, the temperature, the crystallinity and the density of composite materials which have effect on thermal conductivity are also analysed. It is found that with the increasing of filler content, not only HDPE but also silicon rubber can improve its thermal conductive performance, which related to the kind of filler. With the diameter of filler decreasing, the thermal conductivity of plastic and rubber materials could be increased. In the fields of high temperature, the thermal conductivities of HDPE have the trend of decrease with the temperature increasing. The explanation of this change is given. In the view of molecule, the crystallinity which has effect on thermal conductive performance is discussed. With the crystallinity increasing, the thermal conductivity of polymer could be increased. It's useful to improve the thermal conductive performance of polymer materials by decreasing micro-pore and other limitation.