The Study On Thermal Conductive Performance Of Rubber And Plastic Materials

In recent years, with the development of integration and assembly technique, the volume of electronic components and logic circuit become smaller and smaller. So the materials which are insulated and with high thermal conductivity are needed. And that thermal conductive polymer materials are insulated and highly thermal conductive, therefore, the study on thermal conductive polymer materials become very important.In this paper, by means of unsteady state method, a simple new equipment used in measuring the thermal conductivity was designed. This 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 mechanical performance and thermal conductive performance of the three kinds of materials: HDPE/LDPE, LDPE/thermal fills, silicon rubber/thermal fills, are analysed.In HDPE/LDPE, the melt temperature is increasing with the increasing of HDPE. The mechanical performance is improving with the increasing of HDPE. The thermal conductivities of HDPE/LDPE materials with different mixing proportion are approximate, all are increasing at the beginning, reaching the maximum, then reducing until to a certain value.In LDPE/thermal fills, because of the thermal fills, the temperatures of starting to melt are increasing, but approximately the same when the mixing proportions are different. The mechanical performance are reducing with the increasing of thermal fills, the thermal conductive performance are increasing with the increasing of thermal fills.In silicon rubber/thermal fills, the thermal fills make the tensile strength and failure elongation get improved, make the tensile permanence distortion definite elongation stress get worse, make the thermal conductive performance get improved.Furthermore, the internal mechanism of thermal conductibility was discussed. The main points are the effects of influence factors, such as kind and fills, proportion of fills, temperature, crystallinity, specific heat to the thermal conductivity. It is found that filling in either LDPE or silicon rubber with thermal fills can improve its thermal conductive performance. The thermal conductive performance are improving with the increasing of thermal fills, and it is also related to the kind of fills. With the temperature increasing, the thermal conductivities of LDPE/thermal fills and silicon rubber/thermal fills are increasing rapidly at the beginning, then increasing slower, reaching the top and reducing. The explanation of this change is given. The effects of crystallinity to the thermal conductive performance are discussed, the conclusion was made that if we could imcrease the crystallinity of polymer materials, the thermal conductive performance could be improved.