Capsule fillerAdding solid materials to materials can improve the performance of the materials, or it can increase the volume and weight of the materials and reduce the cost of the materials. Generally, water-free, neutral, organic and inorganic substances, metals or non-metal powders that do not react unfavorably with the material components can be used as fillers. Commonly used industrial fillers include kaolin, diatomite, talc, graphite, carbon black, aluminum oxide powder, glass powder, asbestos powder, mica powder, quartz powder, carbon fiber, cork powder, and silicon carbide, etc. Fillers are widely used in the chemical production of plastics processing, rubber processing, papermaking, paint, pesticides, pharmaceuticals and other products, not only improving the performance of these products, but also greatly reducing production costs.

　　Basic characteristics of capsule fillers: The basic characteristics of fillers refer to the characteristics that have a relatively large impact on the performance of fillers and the characteristics that play a leading role in the application of composite materials composed of fillers. Particle shape characteristics and particle size: Particles are the basic units of fillers, and particle shape and size are the basic parameters of particles. The shapes of particles include spherical, cubic, blocky, flaky, fibrous, etc. The size of the particles is determined by the equivalent spherical diameter.

　　Capsule fillerB Particle size distribution: The filler of the capsule filler itself is an aggregate of particles, and cannot be an aggregate of particles with uniform particle size. It is graded by sieving to remove some grade components. Particle size distribution is an important property of the filler, which is usually represented by a particle distribution curve. It directly affects its rheological properties, wear resistance, particle packing and other characteristics.

　　C Specific surface area and surface free energy of particles: Specific surface area is the surface area of a unit mass of filler, denoted by M/G. A large numerical value indicates that the filler provides a large contact area, which involves the adsorption capacity and chemical reaction capacity of the filler, indicating many contact opportunities. Surface free energy refers to the dispersion of solid filler particles in liquid materials. Or the liquid penetrates the filler particles to overcome the energy barrier on the contact surface, because the cohesive force between the molecules is greater than the attractive force between the two different components. Its value is related to the specific surface area and composition of the filler, and directly affects the degree of dispersion of the filler in the polymer material.

　　D Particle packing density: refers to the volume occupied by a certain mass of filler, which directly affects the quality and efficiency of the filler; E Filler chemical composition: indicates the chemical structure of the filler. Two fillers with the same composition exhibit different properties after filling, which indicates that the chemical composition of the filler cannot completely represent its properties. Other properties, such as particle size and particle distribution, also have an important impact on the filling effect.

　　Functional characteristics of capsule fillers: Fillers have many special functions, specifically manifested in: A Optical properties: Light reflectivity, filling has good light reflectivity, which can make the filling color bright, beautiful, and generous. Fluorescent fillers can show signs in low light conditions, and different refractive indices can be used to enhance or weaken light.

　　B Thermal properties: includeCapsule fillerThermal conductivity, specific heat capacity, thermal expansion, thermal stability, etc., directly affect the thermal properties of the filler; C Electrical properties: There are differences between the theoretical and actual electrical conductivity of fillers, which is due to the hydroxyl groups on the surface of the fillers, surface-adsorbed free ions, and impurities of variable valence metal compounds. When using fillers, these factors should be considered for their effect on filler performance.