外加电压对沥青碳纤维/ABS树脂复合材料导电性的影响

INFLUENCE OF EXTERNAL VOLTAGE ON THE CONDUCTIVITY OF COMPOSITES COMPOSED OF CARBON FIBERS AND ABS RESIN

通用级沥青碳纤维与 ABS树脂通过单螺杆挤出机共混后模压成型 ,所制复合材料的电阻率随材料中纤维添加量的增多而迅速降低。当复合材料中纤维添加量较少时 ,材料的电流电压关系不满足欧姆定律所描述的线性关系 ,材料电阻随外电压的增大而减小。随着纤维含量的增加 ,材料电流电压关系的线性度逐渐增大。当纤维含量达到 40 wt%时 ,材料电阻不随外电压的增大而变化 ,材料满足欧姆定律。经外加高电压处理后 ,材料电阻率发生永久性降低 ,其电流电压关系的线性度提高。

Conductive ABS resin composites filled with general pitch-based carbon fibers were fabricated by hot-press moulding after raw materials were preblended through a single screw extruder. The composite resistivity decreases with fibers content going up. The electrical current displays non-linear dependence on the external voltage acted on composites and the resistance of composites varies down with the raise of voltage, which implies that the composites do not meet Ohm's Law. When fibers fraction increases, the linearity between current and voltage goes up correspondingly. For the sample containing fillers of 40 wt%, its resistance remains constant and it satisfies Ohm's Law very well. It is interesting that the high voltage can result in the permanent reduction of composite resistance. And the voltage, which makes the permanent reduction of composites resistance, goes up with the increase of fillers loading. Moreover, the linearity of current and voltage rises after composites were treated by high voltage. All these phenomena can be explained by quantum tunneling model, and the results of this paper provide a new method for improving the conductivity and stability to varied voltage of composites.