摘要
研究了炭黑填充硅橡胶硫化胶的热循环以及热处理过程中的导电行为,发现在热循环中阻温关系曲线逐渐向低电阻方向移动,而在恒温下发生电阻弛豫现象;分析了硫化胶的导电机制,讨论了阻温关系发生移动的原因.
The conduction behavior of carbon black(CB) filled poly(methyl vinyl siloxane)(PMVS) vulcanites undergoing thermal cycles or subject to thermal treatment at given temperatures was investigated. The conduction behavior in PMVS/CB crosslinked composites at room temperature followed the prediction of the statistical percolation theory. The negative temperature coefficient(NTC) effect of resistivity corresponded to thermal activation conduction mechanism, while the positive temperature coefficient(PTC) effect was related to the breakdown of conductive network caused by volume expansion. The results revealed that the resistivity-temperature properties during the thermal cycles was gradually changed towards low-resistance, while the change of resistance with variation of time at given temperatures exhibited resistivity relaxation behavior. The conductive mechanisms and corresponding changes in the structure of PMVS/CB responsible for the resistivity-temperature behavior were discussed. At given temperatures, the tesistance relaxation was strengthened with decreasing CB weight fraction. On the other hand, it is strengthened with increasing ambient temperature at given CB fractions.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第5期952-955,F009,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金重点项目(批准号:50133020)
国家杰出青年科学基金(批准号:50125312)资助.
关键词
炭黑
聚甲基乙烯基硅氧烷
热循环
阻温特性
电阻弛豫
Carbon black
Poly(methyl vinyl siloxane)
Thermal cycle
Resistivity-temperature characteristic
Resistivity relaxation