The Influence of Surface Modification on the Structure and Dielectric Properties for Barium Titanate and Polyimide Composites

如何更好的控制相界面来提高介电性能是目前高分子介电复合材料的研究热点之一。本文采用氨基硅烷、油酸和对氨基水杨酸对纳米钛酸钡进行表面修饰，然后通过原位聚合制备了纳米BaTiO3/聚酰亚胺(PI)复合材料。对表面修饰钛酸钡进行了表征，测量了其复合材料的介电性能。研究发现：三种改性剂均能促进BaTiO3在聚酰亚胺中的分散，并且改善复合材料的介电性能。当BT体积分数为15%时，在频率为1K Hz下，复合材料的介电常数达到30，而介电损耗为0.02。 How to well control the phase interfaces to improve dielectric performance is one of the research hotspots in polymer dielectric composites. In this paper, nanometer barium titanate (BT) was modified by amino silane (KH550), oleic acid (OA), and p-aminosalicylic acid (ASA), then their composites with polyimide (PI) were prepared by in-situ polymerization. The modified BT powders were characterized by various techniques, and their composites were tested with respect to the dielectric properties. The results show that these three organic molecules enable the improvement of the dispersity of nanometer BT in PI host, and thus the dielectric properties of the resulting composites. When PI is loaded with 15 vol% nanometer BT, dielectric constant and loss of the composites is 30 and 0.02, respectively.