高抗冲聚苯乙烯/炭黑导电复合材料 PTC效应的研究

采用SEM、XRP、DSC和体积膨胀等手段对非结晶形HIPS／CB（聚苯乙烯／炭黑）导电复合材料的导电行为进行分析。实验结果表明，HIPS／CB导电复合材料的渗流区域较窄，炭黑含量为30～40g时，电阻发生急剧降低，在渗流阀值附近导电复合材料的电阻率变化最大，跃迁强度为2.2个数量级；HIPS／CB导电复合材料的PTC起始转变温度在85℃左右，与HIPS的玻璃化转变温度接近，HIPS作为非晶材料其体积膨胀较弱，并不足以单独解释PTC效益。

Study on the Positive Temperature Coefficient of the HIPS/CB Conductive Composite Material

The structure/electrical resistively relation in CB -loaded HIPS conductive polymer was studied. Various test instruments such as SEM, X - ray diffraction, DSC, volume thermal expansion and so on were used to analyze the relation of structure and the electrical resistively. As amorphous polymer, HIPS processed PTC effect but the intensity is low. When the CB concentration reached near the percolation threshold, the PTC behavior is the most pronounced and the PTC transform temperature is near the glass transform temperature. Due to the intrinsic feature of amorphous polymer of HIPC, its volume expansion is not enough to explain the PTC behavior when the temperature is increased. The new theory of the binary critical phenomena can be uses to interpret the PTC effect of the amorphous polymer.