Plastic is a high molecular compound polymerized by monomer as raw material through addition polymerization or polycondensation reaction. Its resistance to deformation is moderate. It is composed of synthetic resin and fillers, stabilizers, lubricants, pigments and other additives. The main component of plastic is resin. Resin refers to a polymer compound that has not been mixed with various additives. Resin accounts for about 40%-100% of the total plastic. The basic properties of clinker mainly depend on the nature of the resin, but additives also play an important role. Plastic is an important organic synthetic polymer material with a wide range of applications.
Figure 1. Application of plastic resins.
- Plastic optical fiber: Plastic optical fiber is lighter, softer, more resistant to damage, and has excellent tensile strength, durability, and small footprint. These advantages make plastic optical fiber widely used in automobiles. The plastic optical fiber has a large diameter and a large light transmission capacity. Compared with copper transmission media, it has higher bandwidth capability. The higher the transmission frequency, the lower the cost of using plastic optical fiber. Plastic optical fiber does not produce radiation, and is completely immune to electromagnetic interference, radio frequency infection and noise. This advantage is particularly important for the splitting of video and audio. Plastic optical fibers can be used to obtain high-quality images.
- Plastic piping: Plastic piping is a general term for pipes made of plastic materials. Compared with traditional cast iron pipes, galvanized steel pipes, cement pipes and other pipes, plastic pipes have the advantages of energy saving, material saving, environmental protection, light weight, high strength, corrosion resistance, smooth inner wall and no scaling, simple construction and maintenance, and long service life. It is widely used in construction, municipal, industrial and agricultural fields such as building water supply and drainage, urban and rural water supply and drainage, urban gas, electric power and optical cable sheath, industrial fluid transportation, agricultural irrigation, etc.
- Plexiglass (PMMA): Plexiglass is the common name of Polymethyl methacrylate, abbreviated as PMMA, which is an important thermoplastic. Plexiglass has the advantages of good transparency, chemical stability, mechanical properties, easy dyeing, easy processing, and beautiful appearance. Plexiglass is widely used in commerce, light industry, construction, chemical industry, etc.
- Foamed plastic: Foamed plastic is a type of polymer material formed by a large number of gas micropores dispersed in solid plastic, which is light in weight. It has the characteristics of sound insulation, sound absorption, shock absorption, etc., and has good dielectric properties and is widely used. After blending, filling, reinforcement and other modified plastics, foam plastics have excellent comprehensive properties and can meet the needs of various special purposes. For example, glass fiber reinforced polyurethane foam made by reaction injection molding has been used as structural parts of airplanes, automobiles, and computers.
According to the different physical and chemical properties of various plastics, plastics can be divided into two types: thermosetting plastics and thermoplastics.
- Thermoplastics: Thermoplastics are plastics that melt when heated, can flow to the mold after cooling, and then melt again after heating. Therefore, heating and cooling can be used to make the device produce reversible changes. General-purpose thermoplastics whose continuous use temperature is below 100°C, polyethylene, polyvinyl chloride, polypropylene, and polystyrene are also called the four general-purpose plastics.
- Thermosetting plastics: Thermosetting plastics refer to plastics that can be cured under heat or other conditions or have insoluble (melting) characteristics, such as phenolic plastics, epoxy plastics, etc.
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