多壁碳纳米管分散性对水泥基材料导电性能和电热特性的影响

Effect of Dispersion of Multi-Walled Carbon Nanotubes on Electrical and Electrothermal Properties of Cement-Based Materials

采用分散剂、超声处理及离心机分离作用,得到分散均匀、稳定状态的多壁碳纳米管(MWCNTs)悬浮液和分散不均匀、团簇状态的MWCNTs沉淀,分别将这两种状态的MWCNTs掺入水泥净浆中,研究MWCNTs分散性对水泥基材料电学性能和电热特性的影响。结果表明:MWCNTs在水泥基体中分散均匀时,随MWCNTs掺量的增加试块电阻率下降;当MWCNTs在水泥基体中分散不均匀时,试块的导电性与MWCNTs掺量没有明确的相关性。MWCNTs水泥净浆的电阻率均随测试温度的升高不断降低,当温度超过80℃时,电阻率趋于恒定,并且MWCNTs分散均匀时,水泥净浆电阻率受温度影响的程度随MWCNTs掺量增高而减小;MWCNTs在基体中分散效果好时,水泥净浆因通电引起的升温速率和幅度随着MWCNTs掺量增大而提高。

By process of the dispersant treatment,ultrasonic processing and centrifuge separation,two dispersing states of multi-walled carbon nanotubes(MWCNTs)were attained,that is,in a state of uniformity and stability(well-dispersed)and in a state of uneven dispersion and clusters(undispersed).MWCNTs of two dispersing states were added into cement paste respectively to study the effects of dispersion on the electrical properties and electrothermal properties.The results show that when MWCNTs are dispersed evenly in the cement matrix,the resistivity of the material decreases with the increase of MWCNTs content,while when MWCNTs are dispersed unevenly,the conductivity of the material has no inevitable correlation with content of MWCNTs.The resistivity of MWCNTs cement paste decreases with the increase of the test temperature,and when the temperature exceeds 80℃,the resistivity gradually becomes constant.And when MWCNTs are dispersed evenly in matrix,the influence of temperature on the resistivity of the cement paste decreases with the increase of MWCNTs content.Further more,the rising rate and amplitude of temperature of cement paste increase with the increase of MWCNTs content when electric voltage is applied.