filler

Filler is a solid additive used to improve the properties of composite materials (such as hardness, rigidity, impact strength, etc.) and reduce the cost It is different from reinforcement materials, and the filler is granular The fiber reinforced material is not used as filler Mechanism of fillers: fillers, as additives, mainly play a role by occupying volume Due to the existence of fillers, the molecular chains of matrix materials can no longer occupy all the original space, so that the connected segments are fixed to some extent, and may cause the orientation of matrix polymers Due to the size stability of fillers, the movement of molecular chain in the polymer interface area is limited, which leads to the increase of glass transition temperature, the increase of thermal deformation temperature, the decrease of shrinkage, and the increase of elastic modulus, hardness, rigidity and impact strength The function of fillers: ① to reduce the shrinkage of the molded parts, improve the dimensional stability, surface finish, smoothness and flatness or mattess of the products; ② to effectively adjust the viscosity of the resin; ③ to meet different performance requirements, improve the wear resistance, conductivity and thermal conductivity, etc., most fillers can improve the impact strength and compression strength of the materials, but can not improve the impact strength and compression strength Tensile strength; ④ can improve the coloring effect of pigment; ⑤ some fillers have excellent optical stability and chemical corrosion resistance; ⑥ have compatibilizing effect, can reduce costs and improve the competitiveness of products in the market Types of fillers (1) inorganic fillers and organic fillers (1) inorganic fillers and inorganic fillers are mainly granular fillers made of natural minerals through mining and processing, and a few fillers are made through processing a Silicon oxide and silicate b Carbonates and carbides c Sulfates and sulfides d Titanate e Oxides and hydroxides f Metals ② organic fillers organic fillers are made of natural animals and plants and synthetic organic materials (such as regenerated cellulose, synthetic resin, etc.) (2) inert filler and active filler ① inert filler is directly used to dry or grind natural ore into powder after wet grinding ② there are two methods to make the surface of the active filler coated with coupling agent or natural mineral calcined or both (3) microsphere (solid or hollow) packing the main feature of microsphere packing is that its length is approximately equal in any direction a There are two kinds of glass bead: solid bead (sinking bead) and hollow bead (floating bead) b Polymer microspheres are polymer microspheres made of organic compounds (4) lamellar, fibrous and acicular fillers ① scale fillers are particles that are much longer in two directions than in the third, and have scale shape The whiskers are tiny fibrous single crystals made of silicon carbide, boron nitride, alumina, graphite or beryllium metal oxides (5) glass powder and ground glass fiber filler are made of ground glass or glass fiber They are fillers of thermosetting and thermoplastic matrix They can give products heat resistance and low shrinkage, and improve mechanical properties (6) composite packing is made by combining and modifying two or more kinds of packing with special treatment methods according to the characteristics of different packing.