Polyimide has been treated in different ways, and its characteristics will be quite different. When untreated, in the two states of no tension and tension, the power frequency insulation strength of polyimide film is very large, and it is more suitable as a film-type insulating material for conventional electrical equipment; after soaking in liquid nitrogen, polytetrafluoroethylene The power frequency insulation strength of the film and the polyimide film are equivalent; in the stretched state, the power frequency insulation strength of the polypropylene laminated paper is relatively stable, and there is no obvious change.
Fuzhou University uses biphthalic dianhydride and 4,4'-diaminodibenzyl ether as monomer raw materials, and uses vapor deposition polymerization method to prepare polyimide insulating film. The test results show that the polyimide film is vacuum-treated. After the thermal imidization treatment, the microstructure of the insulating film is improved, the surface is dense and uniform, the particle size of the film layer is small, and the defects and stress in the film are also reduced, which greatly improves the breakdown voltage of the polyimide insulating film. The leakage current density is also very small at higher field strengths.
According to chemical properties, it can be conventionally divided into thermoplastic and thermosetting. Thermoplastic is like ordinary plastics that can be heated and melted, can be injected, extruded, molded, PI100 series, PI200 series, YS20 of Shanghai Resin Institute, P100 of Takasaki, etc. The thermosetting ones contain groups such as double bonds or acetylene groups, similar to unsaturated resins, epoxy resins and other materials, which require high temperature or heating to be cured and formed, such as bismaleimide (BMI), containing benzene Acetylene-terminated polyimides, etc., are mainly used in adhesives and composites.
There are three main types of modified polyimides: polyetherimide, polyesterimide and polyamideimide. Polyetherimide polyimide is an amber transparent thermoplastic, and its molecular structure is: due to the introduction of flexible ether bonds and isopropyl groups into the molecule, the melt fluidity of polyetherimide is greatly improved. The improvement can be processed by ordinary thermoplastic processing methods, such as injection molding, extrusion, and thermoforming.
Polyesterimide has the intentional electrical properties, mechanical properties, heat resistance, solvent resistance, radiation resistance, and processing properties of aromatic polyesters. It can be injected, extruded, and pressed, with good dimensional stability and low cost .
Domestic Business Department:
Lu Yuyun 18012326666
Tel: 86-0514-88381999/ 88360999
International Business Department:
Caoba Industrial Park, Jinghe, Baoying County, Yangzhou City