Preparation And Properties Of Polymer Based High Dielectric Composites Based On Micro-Nano Laminated Technology

High dielectric composites have a wide range of application in high energy storage capacitors, microwave absorbing materials and cable industries.However, the dielectric properties of high dielectric composites put forward higher and higher requirements with the rapid development of electronic information technology industry. At present, the polymer-based dielectric composites have high dielectric loss problems while increasing the dielectric constant. In order to solve this problem, a polymer-based high dielectric composites are prepared by using micro-nano laminated extrusion technology to improve the dielectric constant while maintaining low dielectric loss and high breakdown strength.The main research contents are as follows:1. This paper introduces a new type of laminated device. A single substrate micro-nano laminated extrusion device and double substrate micro-nano laminated co-extrusion device are designed based on this new type of laminated device, and this paper introduce the system composition and working principle and so on in detail. The influence of length of the flow path on the extrusion process is simulated by using polyflow, and the simulation idea provides an important reference for designing micro-nano laminated extrusion device in different applications.2. This paper prepares 1, 9, 81, 729 layers' carbon nanotubes filled with high impact polystyrene (CNT/HIPS) composites with different CNT content by using self-made single substrate micro-nano laminated extrusion device. The dispersion and orientation of CNT in HIPS matrix are analyzed, and the conductivity and dielectric properties of CNT/HIPS multilayered composites are discussed. Due to the polymer melt is subjected to strong shear and tensile forces within the laminated device, the dispersion and orientation of CNT in HIPS matrix increase with the increase of the number of layers. The dielectric constant and dielectric loss increase with the increase with the increase of the number of layers. The orientation of carbon nanotubes destroys the original conductive network of multilayered composites, which affects the AC conductivity of multilayered composites, and the orientation model of carbon nanotubes under the action of micro-nano dragging flow is proposed.3. This paper prepares 2, 8, 32, 128 layers' carbon nanotubes filled with high impact polystyrene (CNT+HIPS)/ high impact polystyrene (HIPS)composites with different CNT content by using self-made double substrate micro-nano laminated extrusion device. The stratification of multilayered composites is analyzed, and the electrical conductivity, dielectric properties and energy storage density of multilayered composites are discussed. The result shows that the real thickness of the micro-layer is close to the theoretical thickness and the interface between the CNT + HIPS layer and the HIPS layer is good. The electrical conductivity of CNT+HIPS/HIPS multilayered composites exhibits significant anisotropy. The CNT+HIPS/HIPS multilayered composites have high conductivity characteristic in the extrusion direction, and exhibits an insulating property in the thickness direction. The design of the alternating layered structure can greatly improve the dielectric constant, and it can maintain low dielectric loss, especially maintain substantially the same dielectric loss as pure HIPS at low frequency (<104 Hz). The paper proposed the interfacial polarization model which explains the phenomenon about the change of dielectric constant and dielectric loss, and the mathematical model is used to explain the reason why the multilayered composites exhibit low dielectric loss. Furthermore, the design of the alternating layered structure can maintain high breakdown strength.In this paper, a single and double substrate micro-nano laminated extrusion device have been successfully developed, and multilayered composites with high dielectric constant, low dielectric loss and high breakdown strength are prepared. This paper provides a novel method to prepare polymer-based high dielectric composites with special space structure.