How are plastics graded?

Plastic grade of 1 to 7 can be seen in the following table:

Plastic is a monomer as raw material, through the polymerization or polycondensation reaction polymerization of polymer compounds (macromolecules), commonly known as plastics (plastics) or resins (resins), can be free to change the composition and the shape of the style of synthetic resins and fillers, plasticizers, stabilizers, Lubricants, color and other additives.

The main component of plastic is resin. The term resin was originally named after the lipids secreted by plants and animals, such as rosin and wormwood, etc. Resin is a polymer compound that has not yet been mixed with various additives. Resin accounts for about 40% to 100% of the total weight of plastic. The basic properties of plastics are mainly determined by the nature of the resin, but additives also play an important role. Some plastics are basically composed of synthetic resins, containing no or few additives, such as plexiglass, polystyrene and so on.

The so-called plastic, in fact, it is one of the synthetic resins, the shape is similar to the natural resin in the pine resin, after chemical means of artificial synthesis, and called plastic.

Expanded Information

Advantages

1. Most plastics are resistant to corrosion and do not react with acids and alkalis.

2. Plastics are cheap to manufacture.

3. Durable, waterproof and lightweight.

4. Easy to be molded into different shapes.

5. It is a good insulator.

6. Plastics can be used to prepare fuel oil and fuel gas, which reduces crude oil consumption.

Disadvantages

1. It is very difficult and economically uneconomical to sort waste plastics for recycling.

2. Plastics are easy to burn and produce toxic gases when burned. For example, polystyrene combustion produces toluene, a small amount of this substance will lead to blindness, inhalation of vomiting and other symptoms, PVC combustion also produces hydrogen chloride toxic gases, in addition to combustion, it is the high temperature environment, which will lead to the decomposition of plastic toxic components, such as benzene.

3. Plastics are made from products refined from petroleum, and petroleum resources are limited.

4. Plastic will not rot even if it is buried in the ground for hundreds, thousands or even tens of thousands of years.

5. Plastics have poor heat resistance and other properties and are easy to age.

6. Because plastic can not be naturally degraded, it has become the number one enemy of mankind, but also has led to the death of many animals tragedy. For example, zoo monkeys, pelicans, dolphins and other animals, will accidentally swallow the tourists threw 1 plastic bottles, and finally due to non-digestive and painful death; look at the beautiful and pure sea, look closer, in fact, floating full of a variety of plastic garbage can not be accommodated by the ocean, in the intestines of a number of dead seabird samples, found a variety of can not be digested plastic.

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