PA 12导电复合材料的结构与性能

Structure and properties of PA 12 electroconductive composites

采用熔融共混的方法制备了炭黑含量不同的聚酰胺(PA)12导电复合材料,研究了复合材料的导电性能、结构以及炭黑的分散状况。复合材料的体积电阻率随炭黑含量的增加而显著降低,导电炭黑的逾渗阈值低于15%。炭黑具有异相成核的作用,可提高PA 12初始结晶温度。复合材料的储能模量随炭黑含量增加而升高,炭黑对PA 12的分子运动有明显的阻碍作用,使复合材料的玻璃化转变温度移向高温方向。炭黑在PA 12基体中分散较均匀,随炭黑含量增加,炭黑颗粒间距减小,使PA 12复合材料具有良好的导电性能,体积电阻率最低为1×105Ω.cm。

A series of polyamide （PA） 12 electroconductive composites with different carbon black （CB） contents were prepared by melt blending. The electroconductive properties, structure and CB dispersion of the PA 12 composites were studied. The volume resistivity of the PA 12 composites decreased significantly as the CB content increased. The percolation threshold for the conductivity of the PA 12 composites was less than 15%. CB actually played a function of heterogeneous nucleation agent, which in turn made the initial crystallization temperature of the composites rose. The storage modulus of the composites increased with the CB content. The existence of CB militated against the molecular motion of PA 12 obviously and, it was such hindrance that facilitated the glass transition temperature of the composites to shift towards the direction of higher temperature. The dispersion of CB in the PA 12 matrix was comparatively homogeneous. The interpartiele spaces of CB correspondingly diminished in case the CB content increased, so that the composites were endowed with superior electroconduetivity, as exemplified by its lowest volume resistivity of 1×10^5Ω·cm.