Comparative Study On Thermal And Electrical Properties Of Orientated Carbon Nano Tubes/polymer Composites

Since the discovery of the carbon nanotubes(CNTs), the super high ductility, strength, large aspect ratio and excellent electrical conductivity of carbon nanotubes make it an ideal reinforcement additive for composites. The mechanical properties, conductive and heat conduction performance of the composite materials have been greatly improved by the compound of carbon nanotubes and polymer composite, while retaining the friendly polymer materials processing. Polymer generally has the low density, good performance of mechanical and friendly performance of processing, but the traditional conductive polymer performance is poor. Because carbon nanotubes with excellent electric conductivity and great length-diameter ratio, join a small amount of carbon nanotubes to polymer matrix with mature technology will be keep polymer in numerous advantages, at the same time it can greatly improve the conductive composite materials, heat conduction performance. CNTs modification of thermal conductive polymer composite material can be the excellent substitute materials in the plastic industry as metal and metal alloy, and other materials, electronic electric heat equipment manufacturing industry in the thermal conductivity of circuit board.The electrical conductivity, percolation threshold, thermal conductivity and its interface thermal resistance and of directional carbon nanotubes in composite material are simulated based on the Effective media Theory. Study found that a small amount of carbon nanotubes will greatly enhance the conductivity of the composite material and thermal conductivity, when the content of carbon nanotubes than composite material seepage threshold. Composite materials of electrical conductivity, thermal conductivity and percolation threshold were affected obvious by the carbon nanotubes directional degree, long size and morphology of the structure. Calculated the composite materials improve conductivity rate varies with the content of carbon nanotubes relation curves, but certain out when the carbon nanotubes aspect ratio for500, composite materials of seepage threshold value can be conductivity low to0.035vOl%. Based on the Rightek Mann-Franz laws on the metal, this paper calculated the lorentz number of the carbon nanotube composite materials. In the numerical, thermal conductivity rate was significantly higher than the electrical conductivity, and other parameters in the same conditions, thermal conductivity and conductivity increases and reduce is directly proportional to the relationship.