1、 ABS material introduction
In terms of chemical composition, ABS is a polymer formed by copolymerization of acrylonitrile A, butadiene B and styrene S. 1,3-butadiene can provide low temperature ductility and impact resistance for ABS; Acrylonitrile provides ABS with hardness, heat resistance, acid and alkali resistance and other chemical corrosion properties; Styrene can provide ABS with hardness, processing fluidity and product surface finish.
In terms of morphology, ABS is an amorphous material, which has many characteristics, such as low temperature resistance, impact resistance, low creep, excellent dimensional stability and ease of processing, as well as high surface hardness and good chemical resistance. By changing the proportion of the above three components, various properties of ABS can be changed. ABS is widely used as engineering plastics.
2、 Basic properties of ABS
The raw material of ABS is light yellow or milky white granular material with certain toughness and density of 1.04~1.06 g/cm3. ABS has strong corrosion resistance to acid, alkali and salt, and is resistant to organic solvent dissolution to a certain extent. It can be mixed with a variety of resins to form blends, such as PC/ABS, ABS/PVC, PA/ABS, PBT/ABS, etc., producing new properties and new applications.
It has good formability under the environment of - 25 ℃~60 ℃. The processed products have smooth and clean surfaces and are easy to dye and electroplating. Therefore, they are often used for household appliances, toys and other daily necessities, such as the well-known "Lego building blocks".
3、 ABS performance
ABS is non-toxic, tasteless, low water absorption, can be made into various colors, and also has 90% high gloss. ABS has a good combination with other materials, so surface printing, coating and plating treatment are easy. The oxygen index of ABS is 18.2, which belongs to a flammable polymer. The flame is yellow, there is black smoke, it is charred but does not drip, and it will emit a special cinnamon flavor. The addition of flame retardant can make ABS become a flame retardant material, ensuring the safety and fire prevention of finished products; At the same time, it has low smoke during combustion, reducing the pollution to the environment.
ABS has high impact strength and surface hardness in a wide temperature range. Its thermal deformation temperature is higher than that of PA and PVC. Its critical surface tension is 34-38mN/cm, and its shrinkage is 0.4% ～ 0.8%. If it is reinforced with glass fiber, it can be reduced to 0.2% ～ 0.4%. The fluidity of ABS melt is better than that of PVC and PC, but worse than that of PE, PA and PS. Like POM and HIPS, ABS melt belongs to non Newtonian fluid and is more sensitive to shear rate.
Mechanical properties: ABS has excellent mechanical properties, excellent impact strength, and can be used at extremely low temperatures. Even if ABS products are damaged, it is only tensile damage, not impact damage. However, the mechanical properties of ABS are greatly affected by temperature.
ABS has excellent wear resistance and oil resistance, so it can be used for bearings under medium load and speed. The creep property of ABS is larger than that of PSF and PC, but smaller than that of PA and POM. The bending strength and compression strength of ABS are poor among plastics.
Thermal properties: ABS is an amorphous polymer with no obvious melting point, high melt viscosity, poor fluidity and weather resistance; Ultraviolet ray can discolor ABS, and the thermal deformation temperature is 70-107 ℃ (about 85 ℃). After annealing, the product can also be increased by about 10 ℃.
However, ABS can still show a certain toughness at - 40 ℃. It can be used for a long time in the temperature range of - 40 ℃ to 85 ℃, and the thermal decomposition temperature is above 270 ℃.
Electrical performance: ABS has good electrical insulation and is hardly affected by temperature, humidity and frequency. It can be used in most environments.
Environmental performance: ABS is not affected by water, inorganic salts, alkali alcohols, hydrocarbon solvents and various acids, but it is soluble in ketones, aldehydes and chlorinated hydrocarbons, and will produce stress cracking due to corrosion by glacial acetic acid, vegetable oil, etc. ABS is easy to degrade under the action of ultraviolet light. After being placed outdoors for half a year, the impact strength decreases by half.
4、 Application of ABS
ABS has excellent performance, impact resistance, high rigidity, oil resistance, low temperature resistance, chemical corrosion resistance, electrical performance, ease of processing, low price, etc. It is widely used in the fields of electronics, instrumentation, automobile, construction industry, etc.
