The Mechanism Of Heat Conduction And The Percolation Effect Of Carbon Filled Rubber

In this paper the thermal conductivity mechanism and percolation effect of carbon filled rubber are studied by using the experimental and theory methods, and then the different thermal conductivity models and thermal conductivity equations are proposed on based of the hot highlights of the current rubber industry. The microstructure of carbon filled rubber is analyzed by the scanning electricity scope experiment and the thermal conductivity mechanism and percolation effect are researched deeply from the mechanism and microstructure.Based on the existing radial tire tread compound original recipes, the carbon N330,N134,N234 and N539 ,which have different diameters and structures, are acted as filler. In all, there are 97 kinds of rubber recipes. The thermal properties are measured by Nanoflash LFA447 laser thermal conductivity instrument. The measuring temperature range is from30℃to140℃.It is found from experiment date that the thermal conductivities of rubbers which filled with different carbons changed with the carbon shares. The thermal conductivity of N330 carbon filled rubber and the N234carbon filled rubber are divided by the volume fraction of 20%; in the front of the point have obvious linear increasing tendency. After the point the thermal conductivity mutations appear, which can be described by percolation theory. The thermal conductivity of N134 carbon filled rubber and N539 carbon filled rubber are illustrated linear increasing tendency, which haven't reached the percolation range. From all the above, the thermal conductivity routine of different kinds of carbon is related with the carbon diameter structure and interface effect. Among the comparisons of four kinds of carbon series, the thermal conductivity of carbon filled rubber is changed best by the carbon N330.The thermal conductivity mechanisms of the carbon filled rubber are got. The carbon distributes in the rubber when the shares of the carbon are minimum. The scene looks like the island model, the carbon is not connected each other. When the filling amount has reached certain degree, the carbon is interacted each other, the net and similar chain is formed in the system, which is called thermal conductivity net chain. When the tendency of these thermal conductivity net chains are paralleled with the heat flux, the thermal conductivity is increased greatly. At the same time the thermal conductivity can be increased greatly, which has percolation effect. But the percolation point is different because of the characteristic and types of the carbon.During the study of the thermal conductivity models and the thermal conductivity equations, the thermal-electricity similar, mixture rules, percolation theory, fractal geometry and so on. The Y.Agari model and Maxwell model are used in the low filling shares, and the cubic model and sphere model built depending on the shape of filler are also used. The divergence of the Maxwell model and cubic model are larger. The modified fact K and the most stacking coefficient ? mare introduced, and then the Maxwell model and the cubic model are used well before the percolation point. The sphere model and Y.Agari model are also used very well before the percolation point.The exponential function between the thermal conductivity and V-Vc is analyzed after the percolation point of the N234 and N330 carbon filled rubber. The current exponential fact t and the other parameters are introduced to get the percolations equations between the thermal conductivity and the V-Vc:After using the equation the acquired equation is reasonable.