[Weekly Topic] Special lecture on polymer materials: “Plastics” – Learn a little every day (4) ABS plastic: “Improve yourself””

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This post was last edited by tclz007 on 2013-12-9 at 19:02. Starting this month, learning activities will be carried out in the field of polymer materials; we hope that fellow enthusiasts will come to learn, offer good suggestions, engage actively in learning, and those who participate in in-depth discussions will receive substantial rewards in terms of wealth and charm~~~! To encourage everyone to come and participate in discussions more actively, as well as to study more diligently, the top ten participants each time will receive a “Motivation Reward for Active Learning.” Some people might think that it’s terrifying to spend their working days doing nothing useful, performing menial tasks without knowing what to do or what to learn; day after day, year after year, with no vision for their future We must start working hard from now on; even if we learn a little knowledge every day, it will add up over time and help us enrich ourselves. We need to set clear goals – only by filling our minds first can we enrich other aspects of our lives as well. . . . . . Just spend a short ten-odd minutes every day, and you will see the future! ! ! (Anyway, I have learned it; whether you learn it or not is up to you. Apart from those experts like Hai Chuan, there are still others who know it.) . . ) Enough talk – let’s start with the basics today!! ABS plastic: The first polymer materials known to humans were extracts from the liquid that flows out when tree bark is cut; they had a viscous consistency, meaning they were fats extracted from trees. Therefore, many people still refer to this type of polymer material as resin. With the development of the modern chemical industry, the polymer materials in use today are all petrochemical products, by-products of petrochemical processes, or petroleum-derived synthetic products. Modern plastics are no longer extracts from trees, but rather petrochemical products. Advantages of plastics: A. Light in weight, with a low specific gravity. B. High strength; many types of plastics have a specific strength greater than that of steel. C. Insoluble in water, resistant to chemical corrosion, as well as acids and alkalis. D. It does not conduct electricity and is an excellent insulating material ； It does not conduct heat; it is an excellent insulating material as well as a sound insulator. E. It is relatively wear-resistant and has unique self-lubricating properties; some of these materials exhibit better fatigue resistance than steel. Disadvantages of POM plastic include: A. Low surface hardness, making it prone to scratches; B. High creep resistance, preventing it from withstanding heavy loads; C. Low elastic modulus; D. Poor resistance to high temperatures. Introduction to ABS: Abbreviation: ABS; Common name: impact-resistant plastic; Scientific name: acrylonitrile-butadiene-styrene terpolymer. English name: acrylonirile butadiene styrene. ABS is one of the five major synthetic resins. It boasts excellent impact resistance, heat resistance, low-temperature resistance, chemical resistance, and electrical properties. It is also easy to process, results in products with stable dimensions and good surface finish. It can be easily painted or colored, and further processed through methods such as surface metal plating, electroplating, welding, hot pressing, and bonding. It is widely used in industries such as machinery, automotive, electronics, instrumentation, textiles, and construction, making it a highly versatile thermoplastic engineering plastic. The largest application areas of ABS are the automotive industry, electronics and electrical appliances, and building materials. Applications in the automotive industry include many components such as car dashboards, body panels, interior trim panels, steering wheels, sound insulation panels, door locks, bumpers, and ventilation ducts. In the field of electrical appliances, it is widely used in electronic and electrical devices such as refrigerators, televisions, washing machines, air conditioners, and computers. In the building materials sector, ABS pipes, ABS sanitary fixtures, and ABS decorative panels are widely used in the building materials industry. In addition, ABS is also widely used in the packaging, furniture, sports and entertainment goods, as well as machinery and instrumentation industries. Composition of ABS: It is synthesized from three chemical monomers – acrylonitrile (C3H3N), butadiene (C4H6), and styrene (C8H8). Each monomer has different properties: acrylonitrile possesses high strength, thermal stability, and chemical stability ； Butadiene possesses toughness and impact resistance ； Styrene features easy processing, high surface finish, and high strength. Morphologically, ABS is an amorphous material. Structural formula: Acrylonitrile butadiene styrene. Characteristics of ABS: 1. Color: The natural color of ABS is that of opaque pale yellow particles with a high degree of yellowness on their surface. 2. Specific gravity: The specific gravity is 1.05 grams per cubic centimeter, making it slightly heavier than water. It features toughness, hardness, and rigidity. 3. Burning characteristics: It burns slowly; it continues to burn even after being removed from the flame. The flame is yellow, with black smoke produced. It becomes soft after burning, does not melt and drip, and emits a distinct cinnamon scent. Performance of ABS: A. Tensile strength, moderate. It has excellent impact strength, and it does not decline rapidly at low temperatures. Generally, ABS has a good gloss, is hard, tough, and rigid, with moderate mechanical properties, making it an excellent material for casings. It is easy to color and undergo surface treatments such as plating. It also has good low-temperature impact resistance and dimensional stability. B. ABS is resistant to water and the erosion of inorganic acids, bases, and salts. But it is not resistant to organic solvents. C. Disadvantages: ABS has poor weather resistance; it is susceptible to the effects of sunlight, which can cause discoloration and brittleness. Classification of ABS plastic: Based on impact strength, ABS can be divided into types such as ultra-high impact resistance, high impact resistance, and medium impact resistance. Depending on the differences in molding processes, ABS can be further divided into types such as injection molding, extrusion, calendering, vacuum molding, and blow molding. Based on their applications and performance characteristics, ABS can also be classified into various types such as general-purpose grade, heat-resistant grade, electroplating grade, flame-retardant grade, transparent grade, antistatic grade, sheet grade, and tube grade. ABS injection molding process conditions: 1. Drying treatment: ABS material is hygroscopic, so it needs to be dried before processing. The recommended drying conditions are 80–90°C for at least 2 hours. 2. Melting temperature: 210~280°C ； Recommended temperature: 245°C. 3. Molding temperature: 25…70°C. (The mold temperature affects the finish of the plastic parts; lower temperatures result in a poorer finish.) 5. Injection pressure: 500~1000 bar. 6. Injection speed: medium to high speed. 7. The product tends to generate static electricity, and its surface is prone to attracting dust. 8. The shrinkage rate is 4‰–8‰. Applications of ABS in automobiles: ① Low-odor ABS. An important goal in automotive interior design is to reduce the volatility of materials in order to improve the air quality inside the vehicle. Materials with low odor are one of the goals pursued by both automobile manufacturers and those who produce automotive materials. Under the conditions of indoor air quality in vehicles, small molecular organic volatiles in plastics can easily migrate to the surface of these plastic products and evaporate into the indoor air, causing an unpleasant odor for the passengers. By selecting an appropriate matrix resin and carrying out necessary modifications, as well as controlling the appropriate processing conditions, ABS materials that meet the standards set by automobile manufacturers can be produced. Low-odor ABS materials are primarily used to manufacture interior components such as door panels, dashboard trim frames, center consoles, and air conditioner vents, especially those components like air conditioner vents that are exposed to higher temperatures and are responsible for air circulation. ②Heat-resistant ABS: For some components that are exposed to high temperatures, the heat resistance of ABS needs to be improved. A common method to improve the heat resistance of ABS is to blend ABS with PC to form an ABS/PC alloy. Heat-resistant ABS is commonly used to manufacture heat-resistant components such as air conditioner outlets and cooling grills. For heat dissipation grills, improving heat resistance prevents component deformation, which in turn stops the plating layer from peeling off due to such deformation; they can also be made of ABS or ASA. Due to factors such as large size and the need for impact resistance, the door panels are also made of PC/ABS alloy. The fenders of luxury cars are also made of ABS/PC alloy. ③Matte ABS: The intense light reflection inside a car’s cockpit can cause discomfort and fatigue in drivers, and it also affects their vision at night. Therefore, matting ABS is widely used in interior components of car cockpits. Since ABS is an engineering plastic with a high level of surface finish, during the modification process we chose a resin grade with a relatively lower surface finish and a wider molecular weight distribution. And flaky or needle-shaped fillers with a large particle size are selected. This improves the surface roughness of the product, thereby causing light to scatter and achieving a matting effect; matting ABS is used in the manufacture of components such as steering wheels and center consoles. ④Electroplated-grade ABS: Although ABS already possesses a good aesthetic appearance, to achieve an even better look, it is often necessary to apply surface finishing treatments such as electroplating or painting to it. Electroplating-grade ABS is obtained by selecting ABS with a certain rubber content and rubber particle size, and then modifying it to increase its polarity. Electroplated-grade ABS is mainly used in components such as heat dissipation grills and decorative markers. ⑤Weather-resistant ABS: Regular ABS tends to degrade under the effects of sunlight and heat and oxygen, resulting in powdering, discoloration, and a loss of some of its mechanical properties. Therefore, weather-resistant ABS is generally used for ABS used in exterior components. There are many varieties of weather-resistant ABS, such as ACS, AES, and ASA. Among them, ASA is currently the variety with the best weather resistance; it is obtained by replacing the butadiene rubber in ABS with acrylate rubber. PC/AS/SEBS alloys also have good weather resistance. Weather-resistant ABS is mainly used to produce automotive exterior components, such as car radiators grills and mirror frames. Special Lecture Series: Lectures on Polymer Materials – “Plastics”. Learn a little every day (6): Polystyrene. “Improve yourself”. http://bbs.hcbbs.com/thread-1257966-1-1.html Lectures on Polymer Materials – “Plastics”. Learn a little every day (5): Polystyrene. “Improve yourself”. http://bbs.hcbbs.com/thread-1257435-1-1.html Lectures on Polymer Materials – “Plastics”. Learn a little every day (4): ABS plastic. “Improve yourself”. http://bbs.hcbbs.com/thread-1257228-1-1.html Lectures on Polymer Materials – “Plastics”. Learn a little every day (3): Polyvinyl chloride. “Improve yourself”. http://bbs.hcbbs.com/thread-1256914-1-1.html Lectures on Polymer Materials – “Plastics”. Learn a little every day (2): Polyethylene. “Improve yourself”. http://bbs.hcbbs.com/thread-1256622-1-1.html Lectures on Polymer Materials – “Plastics”. Learn a little every day (1): Engineering plastics. “Improve yourself”. http://bbs.hcbbs.com/thread-1256345-1-1.html Everyone is welcome to listen to these broadcasts. I hope those who, like me, want to acquire knowledge every day will listen, and that we can all learn together and discuss~~! 【Special Lecture】Special lecture on polymer materials: “Plastics”; continuously being updated. http://bbs.hcbbs.com/thread-1256917-1-1.html