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以聚偏氟乙烯(PVDF)为聚合物基体,钛酸锶钡(BST)为陶瓷相,成本低廉的导电炭黑(CB)为导电相。采用流延加低温热处理的方法制备了一系列高介电柔性复合薄膜。利用阻抗分析仪对薄膜的介电性进行了测试,结果表明,炭黑的填充能有效提高复合材料的介电性能,当体积分数接近渗流阈值6.2%时,CB/BST/PVDF复合材料的介电常数、介质损耗、电导率急剧增加。结合经典渗流理论研究了材料在渗流转变时介电性变化特征及微观机理,利用微电容模型、界面极化理论对这一现象进行解释。
Polyvinylidene fluoride (PVDF) as the polymer matrix, barium strontium titanate (BST) as the ceramic phase, low cost conductive carbon black (CB) as the conductive phase. A series of high dielectric-flexible composite films were prepared by casting and low-temperature heat treatment. The dielectric properties of the films were tested by impedance analyzer. The results show that the filling of carbon black can effectively improve the dielectric properties of the composites. When the volume fraction is close to 6.2% of the percolation threshold, the dielectric properties of the composites Electric constant, dielectric loss, a sharp increase in conductivity. Based on classical seepage theory, the dielectric properties and microscopic mechanism of the material during the seepage transformation are studied. The phenomenon is explained by the micro-capacitance model and the interface polarization theory.