Zhu Tianwen, Qian Chao, Zheng Weiwen, Bei Runxin, Liu Siwei, Chi Zhenguo, Chen Xudong, Zhang Yi, Xu Jiarui
PCFM Lab, GD HPPC Lab, Guangdong Engineering Technology Research Centre for High-performance Organic, Polymer Photoelectric Functional Films, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China
RSC Adv. 2018 Mar 15;8(19):10522-10531. doi: 10.1039/c8ra01373j. eCollection 2018 Mar 13.
In this work, halloysite nanotubes (HNTs) were chosen as the fillers and high performance polyimide (PI) as the matrix to form a series of dielectric composite materials with high dielectric constant, low dielectric loss and excellent heat resistance. Firstly, KH550 was used to modify the surface of HNTs to make sure of a good dispersion of HNTs into the polymer. The results showed that the addition of KH550 modified HNTs (K-HNTs) can improve the dielectric constant of the composite films while maintaining their excellent dielectric loss properties. To further increase the dielectric constant of the HNTs/PI composites, conductive polyaniline (PANI) was used to coat the surface of HNTs to obtain PANI modified HNTs (PANI-HNTs). Compared with the K-HNTs filled systems, the dielectric constant of the PANI-HNTs/PI nanocomposite films is greatly enhanced. The highest dielectric constant of the PANI-HNTs/PI films can achieve 17.3 (100 Hz) with a low dielectric loss of 0.2 (100 Hz). More importantly, the as-prepared composite films have high breakdown strengths (>110.4 kV mm) and low coefficients of thermal expansion, as low as 7 ppm per °C, and a maximum discharge energy density of 0.93 J cm. Also, such properties are maintained stably up to 300 °C, which is critical for manufacturing heat-resisting film capacitors.
在本工作中，选择埃洛石纳米管（HNTs）作为填料，高性能聚酰亚胺（PI）作为基体，以形成一系列具有高介电常数、低介电损耗和优异耐热性的介电复合材料。首先，使用KH550对HNTs的表面进行改性，以确保HNTs在聚合物中良好分散。结果表明，添加KH550改性的HNTs（K-HNTs）可以提高复合薄膜的介电常数，同时保持其优异的介电损耗性能。为了进一步提高HNTs/PI复合材料的介电常数，使用导电聚苯胺（PANI）包覆HNTs的表面，以获得PANI改性的HNTs（PANI-HNTs）。与K-HNTs填充体系相比，PANI-HNTs/PI纳米复合薄膜的介电常数得到了极大提高。PANI-HNTs/PI薄膜的最高介电常数在100 Hz时可达17.3，介电损耗低至0.2（100 Hz）。更重要的是，所制备的复合薄膜具有高击穿强度（>110.4 kV/mm）和低热膨胀系数，低至7 ppm/°C，最大放电能量密度为0.93 J/cm³。此外，这些性能在高达300°C时仍能稳定保持，这对于制造耐热薄膜电容器至关重要。
