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研究了由炭黑(CB)填充聚甲基乙烯基硅氧烷(PMVS)构成的复合交联体系在单轴压力作用下的轴向导电行为.结果表明,当CB质量分数?稍高于渗流阈值?c时,其电阻R首先随压力增加而升高,呈现电阻正压力系数(PPCR)效应,而在较高压力下呈现电阻负压力系数(NPCR).当?>>?时,体系在c最初几次压缩循环中表现为NPCR效应,但压缩循环可以诱发弱PPCR效应的发生.PPCR-NPCR转变是真应力(truestress)控制的过程,反映了体系内部渗流网络的破坏与重组.
The axial conduction behavior of the composite crosslinked system composed of polymethylvinylsiloxane (PMVS) filled with carbon black (CB) was investigated under uniaxial compression. The results show that when the mass fraction of CB is slightly higher than that of seepage When the threshold value is greater than or equal to c, the resistance R first increases with the increase of pressure, showing the effect of positive pressure coefficient of resistance (PPCR) and the negative pressure coefficient of resistance (NPCR) at higher pressure. However, the compression cycle can induce the occurrence of weak PPCR effect.PCR-NPCR transition is the process of truestress control, which reflects the destruction and reorganization of the percolation network in the system.