PET plastic is the abbreviation of Polyethylene terephthalate in English, referred to as PET or PETP. Chinese meaning: polyterephthalate plastics, mainly including polyethylene terephthalate PET and polybutylene terephthalate PBT. Polyethylene terephthalate is also commonly known as polyester resin. It is a condensation polymer of terephthalic acid and ethylene glycol. Together with PBT, it is collectively called thermoplastic polyester, or saturated polyester.
PET plastic has a highly symmetric molecular structure and a certain degree of crystallization orientation, so it has high film-forming and formability. PET plastic has good optical properties and weather resistance, and amorphous PET plastic has good optical transparency. In addition, PET plastic has excellent wear resistance, dimensional stability and electrical insulation.
PET bottles are popular for their high strength, good transparency, non-toxic, anti-penetration, light weight and high production efficiency. a wide range of applications. The molecular chain structures of PBT and PET are similar, and most of their properties are the same, except that the main chain of the molecule has changed from two methylene groups to four, so the molecules are more supple and the processing performance is better.
PET is a milky white or light yellow highly crystalline polymer with a smooth and shiny surface. It has good creep resistance, fatigue resistance, friction resistance, low wear and high hardness, and has the greatest toughness among thermoplastics; it has good electrical insulation properties and is little affected by temperature, but has poor corona resistance. Non-toxic, weather-resistant, chemical-resistant, low water absorption, resistant to weak acids and organic solvents, but not resistant to hot water immersion or alkali.
PET resin has a high glass transition temperature, slow crystallization speed, long molding cycle, long molding cycle, and large molding shrinkage. The dimensional stability is poor, the crystallized molding is brittle, and the heat resistance is low.
Through the improvement of nucleating agent, crystallizing agent and glass fiber reinforcement, PET not only has the properties of PBT, but also has the following characteristics:
1. Thermal deformation temperature and long-term use temperature are the highest among thermoplastic general engineering plastics;
2. Because of its high heat resistance, reinforced PET will hardly deform or discolor after being immersed in a solder bath at 250°C for 10 seconds, making it especially suitable for preparing soldered electronic and electrical parts;
3. The bending strength is 200MPa, the elastic modulus is 4000MPa, the creep and fatigue resistance are also very good, the surface hardness is high, and the mechanical properties are similar to thermosetting plastics;
4. Since the price of ethylene glycol used in the production of PET is almost half that of the butylene glycol used in the production of PBT, PET resin and reinforced PET are the lowest prices among engineering plastics and have a high cost performance.
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