What is the difference between PET and PBT?

Update:16-06-2020
Summary:

Both PET and PBT are thermoplastic polyesters with simi […]

Both PET and PBT are thermoplastic polyesters with similar molecular chain structures and most of the same properties, but their application as engineering plastics is very different. Let's take a look at the difference between the two.
PET: polyethylene terephthalate
PBT: Polybutylene terephthalate
PET has a highly symmetric molecular structure and a certain degree of crystal orientation, so it has high film-forming properties. PET has good optical properties and weather resistance, and amorphous PET has good optical transparency. In addition, PET has excellent abrasion resistance, dimensional stability and electrical insulation. PET bottles are widely used because of their strength, good transparency, non-toxicity, impermeability, light weight, and high production efficiency.


The main applications of PET are:
1. Can be spun into polyester fiber, namely polyester;
2. Can be made into films for substrates, insulating films, product packaging, etc. for recording, video, film, etc.;
3. As a plastic, it can be blown into various bottles, such as Coke bottles, mineral water bottles, etc.;
4. Can be used as electrical parts, bearings, gears, etc.
The structure of PBT and PET molecular chains is similar, and most of the properties are also the same, except that the main chain of the molecule is changed from two methylene groups to four, so the molecule is more flexible and the processing performance is more excellent.
Simply put, PET is mainly used for fibers, beverage bottles, films, sheets, baking-resistant food containers, etc. PBT is mainly used for electronic appliances: connectors, switch parts, household appliances, accessory parts, small electric covers or ( (Heat resistance, flame retardancy, electrical insulation, molding processability); PET high temperature resistance is not higher than PBT, PBT raw materials are basically added glass fiber reinforced rigidity is much better than PET.
PET modified plastic has excellent heat resistance, weather resistance, electrical properties, rigidity and strength, its reinforcement, flame retardant modification and alloying modification can significantly improve its heat resistance, modulus, toughness and dimensional stability And flame retardant, widely used in electronic appliances, automobiles and home appliances.

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