Polyethylene terephthalate (PET) belongs to the family of polyesters. It has a semi-crystalline form when stable. It is recyclable and shows resistance to impact, moisture, alcohols, and solvents.

It is among those plastics which are an important part of your everyday life. The polymer finds use in packaging, fabrics, and the textile industry. It is also used in films to mold parts for automotive, electronics, and many more.

Additionally, continuous efforts are made to tailor PET properties. This improves performance with beneficial cost profiles to meet high-end application demands.

What properties assist in PET selection?

Polyethylene terephthalate is highly flexible, colorless and semi-crystalline resin in its natural state. Depending upon how it is processed, it can be semi-rigid to rigid. It shows good dimensional stability, resistance to impact, moisture, alcohols and solvents.

Key features include:

• Higher strength, heat distortion temperature (HDT) and stiffness than PBT
• Very strong and lightweight & hence easy and efficient to transport
• Good gas (oxygen, carbon dioxide) and moisture barrier properties
• Excellent electrical insulating properties
• Broad range of use temperature, from -60 to 130°C
• Low gas permeability, particularly with carbon dioxide
• Suitable for transparent applications, when quenching during processing
• It doesn’t break or fracture. It is practically shatter-resistant and hence, a suitable glass-replacement in some applications.
• It is recyclable and transparent to microwave radiation.
• It is approved as safe for contact with foods and beverages by the FDA, Health Canada, EFSA & other health agencies. Food contact approved PET grades »
• Chemical properties
• Excellent resistance to alcohols, aliphatic hydrocarbons, oils, grease and diluted acids
• Moderate resistance to diluted alkalis, aromatic & halogenated hydrocarbons

 

What are the limitations of polyethylene terephthalate (PET)?

PET has immensely added to our daily life, but there still exist some drawbacks with the polymer.

The crystallized form of PET has:

• lower impact strength
• lower moldability

How is polyethylene terephthalate (PET) processed?

Polyethylene terephthalate can be easily processed by injection molding and extrusion. It is generally extruded to produce films and sheets and can be later thermoformed. Blow molding is generally used to produce transparent bottles.

Blow Molding

The blow molding process works by reheating a pre-molded PET preform. It is then automatically positioned into a mound.

Extrusion- and stretch blow molding can be used to fabricate polypropylene bottles.

Is polyethylene terephthalate (PET) recyclable?

Polyethylene Terephthalate is 100% recyclable. It is the most recycled plastic worldwide. It can be easily identified by its recycling code .

Which is the best polymer among clear plastics?

When it comes to polymer clarity, Polycarbonate and Acrylic polymers are equally popular. They compete with polyethylene terephthalate for certain applications.

PC has the characteristics of good impact resistance. They are used to manufacture bottles, cans, and containers for packaging beverages. But at the same time, it has a very poor stress-cracking performance. Polyethylene terephthalate has better mechanical strength and its film strength is three times better than PC.

Choosing PET over PC might be meaningful if your application:

Has the potential where the polymer can fail under stress.

Involves exposure to certain oils and chemicals.

Polyethylene terephthalate is chemically resistant to household cleaners, graffiti, alcohol, and acid. It has a greater resistance to a broader range of chemicals than polycarbonate. The chemical resistance of PC is limited, and it is less desirable for harsh environment use.

At the same time, acrylic does not have the impact strength of either polyethylene terephthalate or polycarbonate. While PET products are usually food grade but cannot be used if exposed to UV rays. Acrylic is UV resistant with as little as 3% degradation outdoors over a 10-year period.