高介电低损耗聚合物纳米复合材料的可控制备与性能调控
发布时间：2019-04-23 20:21
【摘要】：具有高介电常数、低介电损耗以及高储能密度的聚合物纳米复合电介质材料在现代电子和电气设备中有广泛的应用前景,研究和开发具有高性能的聚合物纳米复合电介质材料在推动国民经济发展和提升国家防卫能力方面具有极其重要的意义。尽管前人为提升聚合物纳米复合电介质材料的综合性能做出了很多贡献和努力,但依然还有不少问题亟待解决,如纳米填料的分散性问题、纳米填料与聚合物基体之间的界面问题、以及纳米填料的高填充量问题等。为了解决这些问题,本文探索了一系列简单、快速、高效可控的方法,对纳米填料的表面进行功能化改性,通过设计合成不同的界面结构,系统地研究了界面结构对聚合物纳米复合电介质材料性能的影响,并在此基础上,成功地制备了具有优越的介电性能的聚合物纳米复合电介质材料。首先,为了提高纳米颗粒的分散性以及纳米颗粒与聚合物基体的界面相容性,我们分别采用“Grafting from”和“Grafting to”的策略,以钛酸钡(Ba TiO3,BT)纳米颗粒为核,通过原位引发的可逆加成断裂链转移(RAFT)聚合和“巯基-乙烯基”(“Thiol-Ene”)点击化学反应,设计合成了一系列具有核-壳结构的Polymer@BT聚合物纳米复合电介质材料。在这一类材料中,绝缘的聚合物壳不仅可以充当隔离层来防止BT纳米颗粒的团聚,而且还可直接充当聚合物基体。纳米填料与聚合物基体之间通过共价键相连,因此聚合物纳米复合材料中的界面结构很紧密。在这个过程中,我们采用FT-IR、1H NMR、TGA、TEM、动态光散射等测试手段对纳米颗粒的表面改性进行了详细表征,证明了核-壳结构的Polymer@BT纳米颗粒的成功制备。并且,还通过调节单体配比或接枝聚合物链的分子量,对聚合物纳米复合材料的组成或接枝密度进行调控,系统地研究了界面结构对聚合物纳米复合材料介电性能的影响。其次,为了进一步提升介电性能,我们开发了一种新的策略,以改善高介电常数的纳米填料(BT)和铁电聚合物基体聚偏氟乙烯-六氟丙烯[P(VDF-HFP)]之间的界面。首先,通过表面引发的RAFT聚合,在BT颗粒表面引发两种类型的氟代丙烯酸酯单体聚合,合成了具有核-壳结构的Fluoro-polymer@BT纳米颗粒,使颗粒表面的壳层聚合物具有不同的厚度或不同的分子结构。接着,通过溶液共混和热压成型工艺制备了P(VDF-HFP)/Fluoro-polymer@BT纳米复合材料。相应的纳米复合材料的介电性能和能量存储能力分别由宽频介电谱仪和铁电仪进行了测试。结果表明,所制备的纳米复合材料成功地实现了高的储能密度和低的介电损耗。而且,这类P(VDF-HFP)纳米复合材料的介电性能和储能密度可以通过调节Fluoro-polymer@BT纳米颗粒表面含氟聚合物壳的结构和/或厚度进行调控。第三,为了降低聚合物纳米复合材料的介电损耗,提高其击穿强度和储能密度,我们设计合成了具有草莓状核-壳结构的BT-PDA-Ag纳米颗粒,并以P(VDF-HFP)聚合物作为基体,通过溶液共混和热压成型工艺制备了聚合物纳米复合电介质材料。利用多巴胺的自聚合特性和还原性,在BT纳米颗粒表面包覆一层聚多巴胺(PDA),并通过原位还原将Ag纳米颗粒嵌入到壳层的PDA聚合物中。利用Ag纳米颗粒的库仑阻塞效应,成功地抑制了聚合物纳米复合材料内部的泄漏电流、降低了介电损耗、提高了击穿强度和储能密度。最后,为了降低填料含量,制备可以应用于小型化、轻量化以及柔韧化电子电气设备的聚合物纳米复合电介质材料,我们开发了一种精确可控和环境友好的方式来制备含氟聚合物功能化改性的石墨烯(PF-PDA-RGO),用于制备柔性的铁电聚合物基纳米复合电介质材料。与未改性的RGO相比,我们所制备的PF-PDA-RGO在P(VDF-HFP)聚合物基体中具有良好的分散性,相应的聚合物纳米复合材料具有紧密的界面结构,以及较低的逾渗阈值(=1.06 v%)。因此,我们所制备的P(VDF-HFP)/PF-PDA-RGO纳米复合材料在较低的填料含量时即可显示出较高的介电常数,同时还可以保持相对较低的介电损耗和优良的柔韧性。这为制备高性能的柔性纳米电解质材料提供了一条有效的途径。
[Abstract]:the polymer nano composite dielectric material with high dielectric constant, low dielectric loss and high energy storage density has wide application prospect in modern electronic and electrical equipment, The research and development of polymer nano-composite dielectric materials with high performance are of great significance in the development of national economy and the improvement of national defense ability. Although the predecessors have made many contributions and efforts to improve the comprehensive performance of the polymer nano composite dielectric material, there are still many problems to be solved, such as the dispersion problem of the nano-filler, the interface problem between the nano-filler and the polymer matrix, And the like. In order to solve these problems, a series of simple, rapid and high-efficiency and controllable methods are explored, the surface of the nano-filler is functionalized and modified, and the influence of the interface structure on the properties of the polymer nano-composite dielectric material is systematically studied through the design of different interface structures. And on the basis of that, the polymer nano composite dielectric material with excellent dielectric property is successfully prepared. First, in order to improve the dispersibility of the nanoparticles and the interface compatibility of the nanoparticles with the polymer matrix, we adopt the "Grafting from" and the "Grafting to" strategy, respectively, and the nano-particles of the titanium dioxide (Ba _ 3, BT) are the core, A series of Polymer@BT-polymer nanocomposite dielectric materials with a core-shell structure were designed by the in-situ reversible addition-fragmentation chain transfer (RAFT) polymerization and the "Kentucky-vinyl" ("Pol-Ene")-click chemical reaction. In this class of materials, the insulating polymer shell can serve not only as an isolation layer, to prevent the agglomeration of the BT nanoparticles, but also to act as a polymer matrix. The nano-filler is connected with the polymer matrix through a covalent bond, so that the interface structure in the polymer nano composite material is very close. In this process, the surface modification of the nanoparticles was characterized by FT-IR, 1H NMR, TGA, TEM, dynamic light scattering and the like, and the successful preparation of the Polymer@BT nanoparticles of the core-shell structure was proved. And the influence of the interface structure on the dielectric property of the polymer nano composite material is systematically studied by adjusting the monomer ratio or the molecular weight of the graft polymer chain, controlling the composition or the grafting density of the polymer nano composite material. Second, in order to further improve the dielectric properties, a new strategy was developed to improve the interface between the high dielectric constant nanofiller (BT) and the ferroelectric polymer matrix polyvinylidene fluoride[P (VDF-HFP)]. First, through the surface-induced RAFT polymerization, two types of fluoroacrylate monomers are polymerized on the surface of the BT particles, and the Fluoro-polymer@BT nanoparticles with the core-shell structure are synthesized, so that the shell-layer polymers on the surface of the particles have different thicknesses or different molecular structures. Then, P (VDF-HFP)/ Fluoro-polymer@BT nanocomposite was prepared by solution blending and hot pressing. The dielectric properties and energy storage capacity of the corresponding nanocomposites were tested by a wide-band dielectric spectrometer and an iron electrometer, respectively. The results show that the prepared nanocomposite successfully achieves high energy storage density and low dielectric loss. Furthermore, the dielectric properties and the energy storage density of such P (VDF-HFP) nanocomposite materials can be regulated by adjusting the structure and/ or thickness of the fluoropolymer shell on the surface of the Fluoro-polymer@BT nanoparticles. thirdly, in order to reduce the dielectric loss of the polymer nano composite material, improve the breakdown strength and the energy storage density, the BT-PDA-Ag nanoparticles with the strawberry-shaped core-shell structure are designed, and the P (VDF-HFP) polymer is used as a matrix, And the polymer nano composite dielectric material is prepared through a solution blending and hot pressing forming process. A layer of polydopamine (PDA) is coated on the surface of the BT nanoparticle using the self-polymerization characteristic and the reducibility of the dopamine, and the Ag nanoparticles are embedded in the PDA polymer of the shell layer by in-situ reduction. By using the coulomb blocking effect of the Ag nanoparticles, the leakage current in the polymer nanocomposite is successfully suppressed, the dielectric loss is reduced, and the breakdown strength and the energy storage density are improved. Finally, in order to reduce the filler content, a polymer nanocomposite dielectric material that can be applied to a miniaturized, lightweight, and flexible electronic electrical device can be prepared, We developed a highly controlled and environmentally friendly way to prepare a fluoropolymer-functionalized modified graphene (PF-PDA-RGO) for the preparation of a flexible ferroelectric polymer-based nanocomposite dielectric material. The PF-PDA-RGO prepared as compared to the unmodified RGO has good dispersibility in the P (VDF-HFP) polymer matrix, and the corresponding polymer nanocomposite has a compact interface structure and a lower percolation threshold (= 1.06 v%). Therefore, the P (VDF-HFP)/ PF-PDA-RGO nanocomposite prepared by our method can exhibit a high dielectric constant at a lower filler content while still maintaining a relatively low dielectric loss and excellent flexibility. This provides an effective way for the preparation of high-performance, flexible, nano-electrolyte materials.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1;TB33
，
本文编号：2463768
[Abstract]:the polymer nano composite dielectric material with high dielectric constant, low dielectric loss and high energy storage density has wide application prospect in modern electronic and electrical equipment, The research and development of polymer nano-composite dielectric materials with high performance are of great significance in the development of national economy and the improvement of national defense ability. Although the predecessors have made many contributions and efforts to improve the comprehensive performance of the polymer nano composite dielectric material, there are still many problems to be solved, such as the dispersion problem of the nano-filler, the interface problem between the nano-filler and the polymer matrix, And the like. In order to solve these problems, a series of simple, rapid and high-efficiency and controllable methods are explored, the surface of the nano-filler is functionalized and modified, and the influence of the interface structure on the properties of the polymer nano-composite dielectric material is systematically studied through the design of different interface structures. And on the basis of that, the polymer nano composite dielectric material with excellent dielectric property is successfully prepared. First, in order to improve the dispersibility of the nanoparticles and the interface compatibility of the nanoparticles with the polymer matrix, we adopt the "Grafting from" and the "Grafting to" strategy, respectively, and the nano-particles of the titanium dioxide (Ba _ 3, BT) are the core, A series of Polymer@BT-polymer nanocomposite dielectric materials with a core-shell structure were designed by the in-situ reversible addition-fragmentation chain transfer (RAFT) polymerization and the "Kentucky-vinyl" ("Pol-Ene")-click chemical reaction. In this class of materials, the insulating polymer shell can serve not only as an isolation layer, to prevent the agglomeration of the BT nanoparticles, but also to act as a polymer matrix. The nano-filler is connected with the polymer matrix through a covalent bond, so that the interface structure in the polymer nano composite material is very close. In this process, the surface modification of the nanoparticles was characterized by FT-IR, 1H NMR, TGA, TEM, dynamic light scattering and the like, and the successful preparation of the Polymer@BT nanoparticles of the core-shell structure was proved. And the influence of the interface structure on the dielectric property of the polymer nano composite material is systematically studied by adjusting the monomer ratio or the molecular weight of the graft polymer chain, controlling the composition or the grafting density of the polymer nano composite material. Second, in order to further improve the dielectric properties, a new strategy was developed to improve the interface between the high dielectric constant nanofiller (BT) and the ferroelectric polymer matrix polyvinylidene fluoride[P (VDF-HFP)]. First, through the surface-induced RAFT polymerization, two types of fluoroacrylate monomers are polymerized on the surface of the BT particles, and the Fluoro-polymer@BT nanoparticles with the core-shell structure are synthesized, so that the shell-layer polymers on the surface of the particles have different thicknesses or different molecular structures. Then, P (VDF-HFP)/ Fluoro-polymer@BT nanocomposite was prepared by solution blending and hot pressing. The dielectric properties and energy storage capacity of the corresponding nanocomposites were tested by a wide-band dielectric spectrometer and an iron electrometer, respectively. The results show that the prepared nanocomposite successfully achieves high energy storage density and low dielectric loss. Furthermore, the dielectric properties and the energy storage density of such P (VDF-HFP) nanocomposite materials can be regulated by adjusting the structure and/ or thickness of the fluoropolymer shell on the surface of the Fluoro-polymer@BT nanoparticles. thirdly, in order to reduce the dielectric loss of the polymer nano composite material, improve the breakdown strength and the energy storage density, the BT-PDA-Ag nanoparticles with the strawberry-shaped core-shell structure are designed, and the P (VDF-HFP) polymer is used as a matrix, And the polymer nano composite dielectric material is prepared through a solution blending and hot pressing forming process. A layer of polydopamine (PDA) is coated on the surface of the BT nanoparticle using the self-polymerization characteristic and the reducibility of the dopamine, and the Ag nanoparticles are embedded in the PDA polymer of the shell layer by in-situ reduction. By using the coulomb blocking effect of the Ag nanoparticles, the leakage current in the polymer nanocomposite is successfully suppressed, the dielectric loss is reduced, and the breakdown strength and the energy storage density are improved. Finally, in order to reduce the filler content, a polymer nanocomposite dielectric material that can be applied to a miniaturized, lightweight, and flexible electronic electrical device can be prepared, We developed a highly controlled and environmentally friendly way to prepare a fluoropolymer-functionalized modified graphene (PF-PDA-RGO) for the preparation of a flexible ferroelectric polymer-based nanocomposite dielectric material. The PF-PDA-RGO prepared as compared to the unmodified RGO has good dispersibility in the P (VDF-HFP) polymer matrix, and the corresponding polymer nanocomposite has a compact interface structure and a lower percolation threshold (= 1.06 v%). Therefore, the P (VDF-HFP)/ PF-PDA-RGO nanocomposite prepared by our method can exhibit a high dielectric constant at a lower filler content while still maintaining a relatively low dielectric loss and excellent flexibility. This provides an effective way for the preparation of high-performance, flexible, nano-electrolyte materials.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TB383.1;TB33
，
本文编号：2463768
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