Plastic products can be found almost everywhere in our lives today, in shops, food markets, schools and even on the roads. They are found in shops, markets, schools and even on the roads. These plastic products come in all kinds of shapes and sizes, with different uses and corresponding categories. So, do you know what types of plastic there are? Let's find out.
There are many different types of plastic, and they can be classified in different ways. For example, plastics can be classified according to their crystalline form, according to their properties, according to how they behave when exposed to heat, according to their chemical structure, and so on.
1. If we classify plastics according to their crystalline form, we can divide them into crystalline plastics and amorphous plastics. The former refers to those plastics which, under certain conditions, produce a certain geometric structure of their molecules, i.e. a crystalline state, and generally speaking, most crystalline plastics are partially crystalline. The latter refers to those plastics whose molecules are not in a crystalline structure and behave in a disordered manner, and the mechanical properties of such plastics are the same in all directions.
2. If we classify plastics according to their properties, they can be divided into general purpose plastics, special plastics and engineering plastics. General purpose plastics are the most commonly used plastics in our daily lives, which are inexpensive and produced in large quantities, accounting for more than the total production of plastics in general, and are used in various industries. Speciality plastics are those with special functions, such as electrical and magnetic conductivity. Engineering plastics are generally used as engineering parts, such as load-bearing parts, heat-resistant parts, etc. They have excellent performance in pressure, heat and solvent resistance, and are generally produced in small quantities and at high prices.
3. Plastics can be classified into thermoplastics and thermosets if they are classified according to their performance when exposed to heat. The former can be repeatedly melted and moulded at a specific temperature to obtain the same or different finished plastic products, as the process of heating and remoulding involves only physical changes. The latter, on the other hand, will become non-meltable after heating and melting, plasticising and cooling, and will not be malleable after being heated again, so it cannot be recycled. The reason for this phenomenon is that chemical changes will occur during its initial heating, and chemical bonds will be formed between its molecular chains, forming a three-dimensional mesh structure, which not only cannot be heated and melted, but also will not dissolve in chemical solvents.
4、If divided according to the chemical structure, plastics can be divided into many categories. There are polyolefins, polyamides, polystyrene, polyesters, polyalkenoates and polyethers.
The variety of plastics allows them to be used in a wide range of industries.
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