Plasma surface treatment of modified nanoparticles increases interfacial area in composite films

• Categories:Technical Support
• Author:Plasma cleaning machine-CRF plasma plasma equipment-plasma surface treatment machine manufacturer-chengfeng intelligent manufacturing
• Origin:
• Time of issue:2022-04-09
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(Summary description)Plasma surface treatment of modified nanoparticles increases interfacial area in composite films: Due to its excellent dielectric properties, polyimide film has been widely used in variable frequency speed regulation traction motors as a basic insulating material for inter-turn insulation and ground insulation. Studies have shown that high-energy particles and thermal effects generated by corona discharge will damage the organic polymer structure and promote the degradation of polyimide, which is the fundamental cause of the insulation failure of inverter motors. Adding nanoparticles as fillers to polymers will bring special electrical properties to insulating materials, such as high dielectric constant, low loss, and corona resistance. key to performance. However, due to their large specific surface energy, nanoparticles will agglomerate in insulating materials, which greatly reduces the nano-effect. Surface modification of nanoparticles can improve the compatibility of nanoparticles with the matrix and reduce the amount of nanoparticles. Agglomeration to improve the interfacial area between nanoparticles and polymer matrix. Therefore, it is of great significance to study the influence mechanism of the surface modification of nanoparticles on the corona resistance of polyimide nanocomposite films. At present, chemical methods are generally used to modify the surface of nanoparticles, which can improve the electrical properties of nano-dielectrics to a certain extent, but scholars at home and abroad are still exploring methods to further improve the properties of insulating materials. In recent years, low temperature plasma technology has been widely used in the surface modification of polymer materials. Plasma treatment of nanoparticles only changes their surface properties without affecting their own properties, the treatment process is simple, no chemical solvent is required, and the treatment effect is good. Under the action of plasma, a large number of active groups such as hydroxyl (-OH) will be generated on the surface of the nanoparticles, which will react with the silanol bonds generated by the hydrolysis of the silane coupling agent to form hydrogen bonds. After plasma treatment of the surface of the nanoparticles, a strong absorption peak appeared there, indicating that a good interaction was formed between the silane coupling agent and the nanoparticles, and a large amount of the silane coupling agent was coated on the surface of the nanoparticles. The absorption peaks of the nanoparticles treated with plasma and those without plasma treatment were basically the same, indicating that the plasma treatment did not change the chemical bonds of the nanoparticles themselves. Using plasma to treat the surface of nanoparticles can effectively improve the coupling effect of nanoparticles and silane coupling agent, thereby improving the dispersion characteristics of nanoparticles in polyimide composite films and increasing the interface between nanoparticles and polymer matrix area. The adhesive layer is closely connected with the organic and inorganic two phases through the silane coupling agent, and has strong interaction, so the corona resistance is strong. In the boundary layer, the interaction between polymer chains and the bonding layer and inorganic nanoparticles is formed, and the corona resistance is slightly weaker than that of the bonding layer. The loose layer is an interface with weak interaction with the boundary layer, and its corona resistance is weak. When a partial discharge occurs on the surface of the material, the surface of the polymer in the area with high electric field strength is first damaged. When the discharge proceeds to the loose layer, the layer is damaged by the discharge because of its poor corona resistance. When the discharge is further deepened, when the charge enters the boundary layer or the bonding layer, due to the strong corona resistance formed by the strong interaction in the interface area, the discharge effect cannot further damage the area, and instead, it is changed along the interface area to " ” shape development, extending the discharge path, thereby improving the corona resistance of the polymer material. After the nanoparticles are plasma treated, the interface area in the composite film is greatly increased, so that the dielectric double-layer structure in the interface area overlaps, the electrical conductivity of the film is improved, and a conductive channel is formed inside the film along the overlapping area. The dissipation of electric charge inside the film is promoted, the electric field inside the film is improved, and the corona resistance life of the film is improved.