Fillers are widely used in products of the polymer industry. Among the functions of fillers are price reduction, know-how control, improved processability, optical properties, thermal conductivity, control of thermal expansion, electrical properties, magnetic properties, fire delay and improved mechanical properties. Fillers are mostly used in polyvinyl chloride (PVC). In addition, they are also used in olefin polymers, nylons and polyesters.
Fillers were initially used only as additives to improve mechanical properties, but due to some chemical properties such as low specific surface area, reduced tensile or flexural strength. Fillers speed up the molding process by increasing the heat transfer coefficient of the polymer, and generally help reduce the thermal expansion of the polymer. Controlling the size distribution and surface area of ​​particles is one of the important factors in the quality and effectiveness of these materials.