TiC Volume Fraction Dependence of the Electrical Resistivity and PTC Property for TiC Added PMC (polyethylene matrix composites)

摘要

TiC added PMC (polyethylene matrix composites) have been prepared with various volume fractions of TiC. Two types of TiC powder with their different particle diameters, 1.5 ìm (TiC - 1.5 PMC) and 90/m (TiC - 90 PMC), were utilized in the present research. The electrical resistivities of the PMC decreased gradually with increasing TiC volume fraction (V); in the case of smaller particle size, the value of the electrical resistivities at room temperature jumped down in the relatively narrow range of V = 0.40 - 0.42, reaching as low as 0.1 ?cm. The temperature dependencies of electrical resistivities were also measured to examine the possible application of the PMC to PMC PTC thermistors. The resistivity showed a positive temperature dependence and changed abruptly in the tenth order of its magnitude during the melting transition of the polyethylene matrix. The electric current-cutoff characteristics of the PMC indicated excellent features in the over current response despite their low resistivity values, as compared with those of other PTC materials.