Different electrical equipments have different requirements on the performance of insulation materials. Insulation materials for high voltage electrical devices such as high voltage motors and high voltage cables require high breakdown strength and low dielectric loss. The main requirements of low voltage electrical appliances are mechanical strength, elongation at break and heat resistance grade.  
& nbsp; & nbsp; & nbsp; & nbsp; macroscopic properties of insulating materials such as electrical properties, thermal properties, mechanical properties, chemical resistance, climate change resistance and corrosion resistance are closely related to their chemical composition and molecular structure. Inorganic solidInsulating materialsIt is mainly composed of silicon, boron and a variety of metal oxides, mainly of ionic structure. Its main characteristics are high heat resistance, working temperature is generally higher than 180 C, good stability, good resistance to atmospheric aging, chemical resistance and long-term aging under electric field. However, it has high brittleness, low impact strength, high pressure resistance and low tensile strength, and poor workmanship. Organic materials are usually polymers with average molecular weight ranging from 104 to 106, and their heat resistance is usually lower than that of inorganic materials. The heat resistance of materials containing aromatic rings, heterocycles and silicon, titanium and fluorine is higher than that of general linear polymer materials.  
& nbsp; & nbsp; & nbsp; & nbsp; the important factors affecting dielectric properties of insulating materials are the strength of molecular polarity and the content of polar components. The dielectric constant and dielectric loss of polar materials are higher than those of non-polar materials, and it is easy to adsorb impurity ions to increase conductivity and reduce their dielectric properties. Therefore, attention should be paid to cleanliness and pollution prevention in the manufacturing process of insulating materials. The dielectrics used in capacitors require high dielectric constant to improve their ratio characteristics.