The Common Seen Plastics (Part Two)

6. ABS or acrylonitrile-butadiene-styrene copolymer
Main applications of ABS
ABS is widely used in various shells of electrical appliances, components of office supplies, safety helmets, door and window pipes. ABS is often used for blending and modifying other plastics in the industry.
 
Using tips
ABS is non-toxic, but it is mostly used in structural materials. It is rarely used in the packaging of daily utensils. ABS has many advantages, but it still has the common characteristics of plastics, that is, not being heat resistant. Of course, the temperature requirements for normal use of the electrical enclosure can still be met.
 
7. PA or polyamide
Main applications of PA
Speaking of PA, there is another name for PA, that is, nylon. Everyone must be familiar with it. The polyamide family is very powerful, PA6, PA66, PA11 and PA12 all have excellent physical and chemical properties. This is also the reason why PA is widely used in the electronics and automotive industries. In daily life, nylon ropes and nylon stockings are also common seen items. The spun PA fiber is called chinlon and used for fishing wire, fishing nets, ropes and conveyor belts.
 
Using tips
PA has great molecular weights and is non-toxic. However, it is often mixed with other plastics  due to its easy moisture absorption and performance changes when used alone. Some additives are used when the plastics are mixed, and these additives may be toxic. Nylon has good heat resistance and deformation resistance. Therefore, it can even be used in the manufacture of engine parts. Although it cannot be compared with cermet materials that can work at hundreds of degrees Celsius, the operating temperature of 200 degrees Celsius is enough to surpass that of most plastics.
 
8. PC or polycarbonate
Main applications of PC
PC has excellent mechanical properties, toughness, rigidity, and good light transmission. It is often used in transparent water cups, nursing bottles, drinking buckets, lenses and lampshades in daily life.
 
Using tips
PC is non-toxic. However, some people worry that there will be residual or decomposed bisphenol A in the synthesis process of bisphenol A PC. Bisphenol A is a toxic substance. In addition, the widely used PC synthesis method uses highly toxic phosgene. For these reasons, PC plastics have been questioned a lot. In fact, PC will be washed and precipitated in the final stage of synthesis to remove unreacted bisphenol A and salts. The PC processing requires strict drying to avoid decomposition. Although PC products may be in contact with water for a long time during use, they will not decompose below the upper limit temperature of the container. Some studies have found that the temperature for the thermal decomposition of PC with a qualified initial phenol content must reach about 200°C, which far exceeds the normal use temperature of water cups.
 

9. Composites

Because it is difficult for a single plastic to meet complex use requirements, different plastics are often mixed in the plastics industry to make plastic alloys, which can not only take advantage of the advantages of different materials, but also save the cost of developing new materials.
 
Main applications of composites
Plastic alloys are widely used in various structural materials. For example, mobile phone shells are mostly made from PC-ABS alloys. Some sewer pipes are made of two kinds of PE alloys in order to meet the performance and processing needs, which are called doublet polyethylene.
 
Using tips
Although combining the advantages of multiple plastics, the composite is still plastic after all. Heat resistance is still a pain in the ass. However, in actual applications, most products will not be exposed to high temperatures. As long as you pay attention to the application environment, plastic is definitely a good cheap and suitable material. There will be relevant national mandatory standards for plastics that are in contact with food and drugs, and the standards are relatively high. As long as the use of plastics and related additives is regulated, the public's health risks will be minimized. There are pros and cons even for permission of the FDA which concerns life and death. The formulation of ISO, national standards or other standards is similar, and you must not give up eating for fear of choking.