炭黑填充橡胶复合材料的高频介电特性

High-frequency Specific Dielectric Properties of Carbon Black Filled Rubber Composites

研究了炭黑(CB)结构和橡胶基体极性对复合材料在高频区介电特性的调控作用.结果表明,与极性较强的丙烯酸酯橡胶体系相比,非(弱)极性硅橡胶体系与CB相互作用较弱,渗流阈值较低,界面极化弱,高频区介电常数随频率增大衰减较小. CB粒径大且比表面积小,虽不利于渗流网络的形成,但高频介电特性随频率衰减较小.比表面积小且结构度低的CB填充弱极性的硅橡胶体系在高频区具有较大介电常数,有望实现人体肌肉和脂肪的宽频化介电特性仿真.

In order to develop high-performance microwave human tissue-equivalent materials,it is a great challenge to endow polymer composites with tunable high-frequency specific dielectric properties.The effects of carbon black(CB)particle size,specific surface area,structure and the CB-matrix interaction on electrical conductivity and high-frequency specific dielectric properties of rubber composites were systematically investigated in this paper.The results show that the percolation threshold is high in CB-filled strong polar acrylic rubber(AR)composites,and the addition of CB can enhance the low-frequency dielectric constant due to strong CB-AR interfacial interactions.However,the dielectric properties decay quickly with increasing frequency,resulting from the strong interfacial polarization.While in the case of weak polar(nonpolar)silicone rubber composites,the dielectric properties at high frequencies decay relatively slowly with increasing frequency.Although CB particles with big size,small specific surface area and low structure are not conducive to form the percolation network,the high-frequency dielectric properties attenuate slowly with an increase of frequency.The results reveal that it is possible to simulate the broadband dielectric properties of human muscle and fat with CB-filled silicone rubber composites.