聚丙烯/氮化硼纳米片复合薄膜的制备及介电储能性能研究  

Preparation of polypropylene/BNNSs composite films and studies on their dielectric and energy storage properties

作　　者：于海生 王瑶[1] 邓元[1] YU Haisheng;WANG Yao;DENG Yuan(School of Material Science&Engineering, Beihang University, Beijing,100191, China;AVIC Beijing Keeven Aviation Iustrument CO.,LTD., Beijing,101300,China)

机构地区：[1]北京航空航天大学材料科学与工程学院,北京100191 [2]北京青云航空仪表有限公司,北京101300

出　　处：《功能材料》2020年第7期7141-7147,共7页Journal of Functional Materials

基　　金：国家自然科学基金面上资助项目(51872009)。

摘　　要：聚丙烯(PP)薄膜已广泛应用于薄膜型电容器和静电储能元件,但较低的介电常数限制了其进一步应用。本文以PP为基体材料,通过掺杂低含量的六方氮化硼(h-BN)二维纳米片,制备出聚丙烯/氮化硼纳米复合薄膜,以提高PP介电常数。其中一个关键因素是调控两相界面,以获得h-BN在PP中的良好分散和与基体的紧密结合。本论文通过超声剥离的方式制备少层氮化硼纳米片(BNNSs),并采用盐酸多巴胺(PDA)的非共价聚合反应进行包覆,得到了BNNSs@PDA。通过XRD、FT-IR和TEM表征了BNNSs@PDA的形貌,验证了核-壳结构的直径约150~200 nm,最小厚度约3 nm,有机PDA壳层平均厚度约为7nm。将BNNSs@PDA与PP复合得到薄膜,通过SEM、耐压测试仪、阻抗分析仪等设备对薄膜的微观结构、击穿性能和介电性能进行了研究。结果表明:在BNNSs@PDA的含量仅为1%(质量分数)时,复合材料的介电常数提高至5.62,损耗仅为0.006,理论储能密度高达7.42 J/cm^3,是纯PP薄膜的4.8倍。以上结果表明:BNNSs@PDA与PP良好的界面、二维纳米片在面内的取向分布,有效阻碍了外电场下电树枝的扩展,抑制了载流子的传输作用,同时引入了界面极化,从而有效提高了复合薄膜的介电和击穿性能。Polypropylene(PP)films have been widely used in thin film capacitors and electrostatic energy storage devices.However,its further application are limited by low dielectric constant.In this paper,PP/BN nanocomposite films were prepared by doping low content hexagonal boron nitride(h-BN)two-dimensional nanosheets with PP as the matrix material to improve the dielectric constant of PP.One of the key factors is to control the two-phase interface to obtain a good dispersion of h-BN in PP and a close combination with the matrix.BNNSs with few-layer were prepared by sonication-assisted hydrolysis and exfoliation method,and then the organic PDA nanolayers were coated by dopamine self-polymerization.The morphology of BNNSs coated with PDA was characterized by TEM,XRD and FT-IR.The diameter of core-shell structure was about 150-200 nm,the minimum thickness was about 3 nm,and the average thickness of organic PDA shell was about 7 nm.PP based composite films with different contents of few-layer BNNSs@PDA were prepared by solution casting method.The dielectric properties and breakdown strength of the films were studied by means of SEM,voltage withstanding test equipment and impedance analyzer.The results showed that when the content of BNNSs@PDA was only 1wt%,the dielectric constant of the composite material increased to 5.62@1 kHz,the loss was only 0.006,and the theoretical energy storage density reached 7.42 J/cm^3,which was 4.8 times higher than neat PP film.The above results show that BNNSs@PDA has a good binding force and compatibility with PP.The two-dimensional sheet structure with orientation distribution effectively hinders the expansion of the electrical trees under the external electric field,inhibits the transmission of carriers,and causes the interface polarization,thus effectively improving the dielectric and breakdown properties of the composite film.

关 键 词：聚丙烯 氮化硼纳米片 复合材料 核壳结构 介电性能 

分 类 号：TB34[一般工业技术—材料科学与工程] TQ325.14[化学工程—合成树脂塑料工业]