炭黑填充聚偏氟乙烯PTC复合材料研究

STUDIES ON RESISTANCE BEHAVIORS OF PTC MATERIAL OF POLY (VINYLIDENE FLUORIDE) FILLED WITH CARBON BLACK

研究了炭黑（ＣＢ）浓度、热历史和辐照对ＰＶＤＦ／ＣＢ复合物电阻行为的影响。结果表明，最大ＰＴＣ强度发生在临界浓度Φｃ处，Φｃ略大于渗流阈值Φｐ，渗流区以外基本无ＰＴＣ效应。热处理对电阻率－温度行为的影响由结晶状态（结晶度和结晶形态）造成的。结晶形态愈复杂，临界温度以下的正温度系数效应愈明显。结晶度越大，ＰＴＣ强度越大。并用ＤＳＣ测试结果解释了这一现象，４０Ｍｒａｄ以下剂量γ－６０Ｃｏ辐照能削弱ＮＴＣ效应，但不能完全消除。

The effects of content of carbon black(CB), the thermal history of poly(vinylidene fluoride) (PVDF) and the irradiation of γ60Co on resistance behaviors of PVDF/CB compound were reported. As a result, largest PTC intensity appears in the vicinity of the critical content(Φc) of PTC material, which is slightly larger than the percolation threshold(Φp). There is almost no PTC effect where the content of CB lies outside the percolation area. The larger the crystallinity, the higher the PTC intensity. The result of DSC measurement uncover the mechanism of these phenomena. NTC effect of PVDF/CB compound can be weakened by γ60Co irradiation, but cannot be eliminated completely during irradiating below 40 Mrad.