0ne Structure of pet

Pet is an organic polymer, which is composed of carbon, hydrogen and oxygen. The molecular structure is as follows: H - [och2ch2-ooc-co] - ohpet is usually formed by direct esterification or transesterification of terephthalic acid (PTA) or dimethyl terephthalate (DMT) with ethylene glycol (eg) to form polyethylene terephthalate (PET), and then to form polyethylene terephthalate by solid-state polycondensation. The chemical reaction equation is as follows: hooc-cooh + 2hoch2ch2oh "catalyst base ho-ch2ch2-ooc-coo-ch2ch2oh + 2H2O

Two Physical properties of pet

Pet can be divided into homopolymer and copolymer pet according to polymerization methods, and can be divided into textile pet, bottle grade PET and sheet pet according to their application. The physical properties of bottle grade PET are shown in Table 1.


Table 1 physical properties of bottle grade PET

Item property value unit

1.density 1.4 kg / cm3

2.The average molecular weight is 25000 ~ 30000

3.IV value 0.70 ~ 0.85

4.melting point 250 ~ 260 ℃

5.AA content ≤ 3 mg / kg

6.moisture ≤ 0.4%

The particle shape is cylindrical or parallelepiped