热处理N990炭黑及其PTC复合材料的电性能

Heat Treatment of N990 Carbon Black and Electrical Properties of PTC Composites

将N990炭黑进行高温热处理，把热处理后的炭黑与高密度聚乙烯熔融混合制成复合材料。采用BET、XRD和XPS方法研究热处理炭黑的结构，电阻-压力曲线评价其导电能力，电阻率-温度曲线研究其复合材料的PTC特性。结果表明，与未处理炭黑相比，高温热处理N990炭黑的晶相结构和颗粒尺寸没有明显变化，但热处理使炭黑的比表面积显著增大，表面氧元素明显减少，导电能力增加1倍以上。热处理炭黑复合材料能达到9个数量级以上的高PTC强度，同时室温电阻率下降了40％～90％。

Carbon black N990 was treated at high temperature and then incorporated into HDPE by melt-mixing to prepare composite. The treated carbon black was characterized with BET, XRD and XPS, and its conductivity was evaluated by resistance-pressure curve. PTC characteristics of the composites were estimated by resistivity-temperature curves. As a result, treated N900 shows no obvious change in crystalline structure and particle size as compared with untreated one, but great increase in specific surface area and apparent decrease in oxygen content on its surface, resulting in an increase in its conductivity by more than 1 times. The composites also keep high PTC intensity above 9 orders of magnitude, and meanwhile room rsistivity could decrease by 40%～90%.