Preparation And Properties Of High Thermally Conductivie ABS/CBT Composites

In recent years, thermal conductive polymers have been gradually used in manyfields including electrical and electronic engineering, LED, heat transfer engineering,cooling engineering and other aspects due to their lightweight, corrosion resistanceand easy-molding. Since the polymer is a poor conductor of heat a lot of heat conduc-tive filler (generally more than30volume percent) are usually added in it in order toimprove the performance of the thermal conductivity. However, excessive fillers canimpair the mechanical properties of the polymer material system and make moldingextremely difficult, which restricts the application of the materials. In this paper thecomponents of polymer composite materials were firstly designed and then their prop-erties were evaluated. After that, the thermal conductive materials were designed withtheir properties researched, which can provide an experimental basis for preparationof high thermal conductive and easy processed polymer composites.As a new kind of resin, CBT has excellent workability and compatibility. It isfound that a small amount of CBT resin can significantly improve the rheologicalproperty and lower the processing energy consumption and the molding temperatureof ABS resin with almost no effect on its mechanical strength. In this study,5weightpercent is considered as the optimal ratio for ABS resin filled with CBT resin. Thenthe thermal conductivity ABS/graphite composite system is studied. With40weightpercent of graphite filled, the thermal conductivity of material increases notably to1.17W m-1K-1while the processing viscosity increases obviously and the mechanicalproperties decrease significantly.On the basis of earlier studies ABS/CBT composite filled with thermal conduc-tive graphite is designed and prepared. It is founded that the mechanical propertiesand thermal conductivity of the composite are excellent and the processing propertiesare also superior. With the presence of5wt%CBT and the presence of20wt%graph-ite, the mixing torque of the thermally conductive composite material is reduced about15.4%, the energy consumption is reduced by26.4%, and the injection molding tem-perature is reduced about20℃. The tensile and bending strength of the compositeis almost not affected by the addition of CBT resin, while the impact strength is in-creased by12.7%. It is proved that the thermal conductivity is improved significantly.In addition, with the higher thermal conductivity of the filler content, the thermalconductivity of the composite is improved more obviously. For instance, when thegraphite content is40weight percent, the thermal conductivity coefficient can reach1.43W m-1K-1, which is about22.2%more than that of an ABS/graphite composite and is about7times higher than that of a pure ABS.Moreover, the coupling agent was also used for surface treatment of thermalconductive graphite. It is proven that an appropriate amount of coupling agent caneffectively improve the mechanical properties and thermal performance of compositematerials. When the coupling agent is about1.5%the weight of graphite, the compo-site material achieves the best overall performance and the thermal conductivity in-creases about11.4%. In addition, the influences of carbon fiber on the properties ofthermal conductive composite material were studied. It is indicated that the thermalconductivity of composite material increases by nearly50%with the carbon fiber of10weight percent, and the mechanical strength is also improved.