structure
ABS resin is a graft copolymer of acrylonitrile, 1, 3- butadiene and styrene. Its molecular formula can be written as (C8H8 C4H6 C3H3N) x, but in fact it is often a mixture of graft polymer containing butadiene and acrylonitrile-styrene polymer, in which acrylonitrile accounts for 15%~35%, butadiene accounts for 5%~30% and styrene accounts for 40%~60%.
With the adjustment of the proportion of the three components, the physical properties of the resin will change to some extent:
1, 3- butadiene provides low-temperature ductility and impact resistance for ABS resin, but too much butadiene will reduce the hardness, luster and fluidity of the resin;
Acrylonitrile provides ABS resin with hardness, heat resistance, acid resistance, alkali resistance and salt resistance.
Styrene provides ABS resin with hardness, processing fluidity and product surface smoothness.
nature
ABS resin is a light yellow solid with certain toughness, and its density is about 1.04~ 1.06 g/cm3. It has strong corrosion resistance to acid, alkali and salt, and can also tolerate the dissolution of organic solvents to a certain extent.
ABS resin can work normally in the environment of -25℃~60℃ and has good moldability. The surface of the processed product is smooth and easy to dye and electroplate. Therefore, it can be used in household appliances, toys and other daily necessities. Common Lego bricks are ABS products.
ABS resin can be mixed with various resins to form a * * * mixture, such as PC/ABS, ABS/PVC, PA/ABS, PBT/ABS, etc. New properties and new application fields are generated. For example, transparent ABS resin can be made by mixing ABS resin with PMMA.
produce
ABS has two main industrial production methods:
Acrylonitrile-styrene polymer (AS) and polybutadiene (B) are mixed, or two kinds of latex are mixed and polymerized;
Acrylonitrile and styrene monomers were added to polybutadiene latex for graft copolymerization.
The raw materials and energy needed to produce 1 kg ABS resin are equivalent to about 2 kg of oil.
Chi Mei Industry is the world's largest manufacturer of ABS resin, and its factories in Tainan and Zhenjiang produce about 6.5438+0.3 million tons of ABS resin every year. Other major ABS resin manufacturers include Bayer Chemical, LG Chemical, General Plastics, BASF and Dow Chemical.
Structure, properties and application in ABS resin, rubber particles are dispersed in the continuous phase of SAN resin. When impacted, the crosslinked rubber particles bear and absorb this energy, which disperses the stress, thus preventing the crack from developing and improving the tear resistance.
The purpose of graft polymerization is to improve the compatibility and adhesion between rubber particle surface and resin phase. This is related to the amount of free SAN resin and the composition of SAN resin grafted on the rubber backbone. The difference of acrylonitrile content between the two resins should not be too big, otherwise the compatibility is not good, which will lead to the interface cracking between rubber and resin.
ABS resin can be processed into plastic by injection molding, extrusion, vacuum, blow molding, calendering and other methods, and can also be processed by mechanical, adhesive, coating, vacuum steaming and other methods. Because of its excellent comprehensive performance and wide application, it is mainly used as engineering materials and household appliances. Because of its good oil resistance, acid resistance, alkali resistance, salt resistance and chemical reagent resistance, as well as its electroplating property, the plated metal layer has the advantages of good luster, light specific gravity and low price, and can be used to replace some metals. It can also be synthesized into self-extinguishing, heat-resistant and other varieties to adapt to various uses.