Abstract
The effect of surface treatment of carbon black (CB) particles on the electrical conductivity of CB filled polymer is investigated in relation to the blending of matrix polymers. High density polyethylene (PE), polypropylene (PP), and the PP/PE polymer blend (weight ratio of PP/PE=40/60) are used as the matrix polymers. Silane coupling agents ; n-propyltrimethoxysilane (PS) and γ-aminopropyltrimethoxysilane (APS), are used for the surface treatment of CB particles. The following results are obtained from the electrical resistivity measurement of the composite : The percolation threshold ; the CB content at which the electrical resistivity of composite begins to decrease drastically, lowers by the blending of matrix polymers ; PP and PE. The percolation threshold of composite lowers by the surface treatment of CB with APS. The transmission electron microscopy (TEM) of the composites also shows the following results : CB particles in the PP/PE matrix preferentially dispersed in the PE phase. With increasing of the CB content, the PP phase which does not contain CB changes from continuous (the composite is insulating) to disperse (conductive).The threshold of CB content depends on the surface treatment of CB particles. The percolation threshold=1.5 phr is attained by the APS treatment of CB in the PP/PE and PE composites.
