Plastic material properties

What is plastic?

  Plastic is a general term for a class of plastic polymer materials under certain conditions. Generally, they are divided into thermosetting plastics and thermoplastics according to their hot melt properties. It is one of the three major organic polymer materials in the world (the three major polymer materials are plastic, rubber, and fiber). The English name of plastic is plastic, commonly known as: plastic. There are many kinds of plastics and many processes. This material only introduces some plastic materials for injection molding.

  Why do some people call plastic resin?

  The earliest known polymer materials are the extracts of the liquid flowing out after the bark is cut, which is viscous, that is to say, it is the resin extracted from the tree. Therefore, there are still many people who call this polymer material resin. But with the development of modern chemical industry, the polymer materials used now are all petrochemical products or by-products of petrochemicals or synthetic petroleum products. Modern plastics are not tree extracts, but petrochemicals.

   Color and grade of plastic

After the general plastics are synthesized, they are all flour-like powders from the synthesis tower, which cannot be used to directly produce products. It is also called powder, which is a pure plastic. It has poor fluidity, low thermal stability, easy aging and decomposition, and is not resistant to environmental aging; therefore, in order to improve the above defects, people add heat stabilizers to resin powder to resist aging. Add plasticizers to increase its fluidity, and produce plastic varieties of different grades with special properties that are suitable for various processing techniques. Therefore, there are many grades of the same plastic variety, such as: ABS has injection molding grade, extrusion grade, electroplating grade, high rigidity, great flexibility, etc. The plastics used, they are all pelletized, they are all pellets. Each grade of plastic is suitable for each process, or injection molding, or extrusion, or calendering, or blister, etc.

  Molecular structure of plastics

The molecular structure of general plastics is a linear polymer chain or a branched polymer chain segment, including crystalline and non-crystalline. The properties of plastic materials have a great relationship with their crystalline properties and their molecular structure. It is also closely related to its constituent elements. Generally speaking, the greater the crystallization rate of plastics, the poorer its light transmittance; those with aliphatic, amino, and alcohol groups are more absorbent. , It is easier to decompose due to the action of water, and it is more difficult to dry during processing; with olefin groups, the flexibility of plastics is good, with benzene rings, plastics are relatively rigid. Due to the vastly different molecular structures of plastics, different varieties have been formed with very different performances, and there are tens of thousands of products of different brands.