What is the Difference Between PET and PP Plastic

The main difference between PET and PP plastic is that PET is formed through the polymerization of terephthalic acid and ethylene glycol, while PP is produced by the polymerization of propylene.

Polyethylene terephthalate (PET) and polypropylene (PP) are two types of plastic polymers with distinct characteristics. Understanding the differences between PET and PP is crucial for selecting the most suitable material for specific applications.

Key Areas Covered

1. What is PET Plastic
      – Definition, Features 
2. What is PP Plastic
      – Definition, Features 
3. Similarities Between PET and PP Plastic
      – Outline of Common Features
4. Difference Between PET and PP Plastic
      – Comparison of Key Differences
5. FAQ: PET and PP Plastic
      – Frequently Asked Questions

Key Terms

PET Plastic, PP Plastic, Polyethylene Terephthalate, Polypropylene

Difference Between PET and PP Plastic - Comparison Summary

What is PET Plastic

Polyethylene terephthalate, commonly known as PET, is a versatile thermoplastic polymer widely used in the production of various consumer products, packaging materials, and textiles. Its chemical structure consists of repeating units of ethylene glycol and terephthalic acid, resulting in a linear, high-molecular-weight polymer. This polymerization process yields a clear, lightweight, and durable material with numerous desirable properties.

PET plastic is perhaps most recognized for its extensive use in the production of beverage bottles, food containers, and packaging materials. Its transparency allows consumers to easily identify the contents, while its lightweight nature reduces transportation costs and environmental impact. Additionally, PET is resistant to moisture and chemicals, contributing to the preservation of the integrity and freshness of the packaged goods.

Compare PET and PP Plastic

One of PET’s significant advantages is its recyclability. The material can be collected, sorted, and processed to create recycled PET, commonly referred to as rPET. Recycling PET not only conserves resources but also helps reduce the environmental impact associated with plastic waste. Many industries and consumers are increasingly embracing the use of recycled PET in the manufacturing of new products, fostering a more sustainable approach to plastic consumption.

Beyond packaging, PET has applications in textiles, where it is used to create fibers for clothing and other fabrics. Known for its strength, flexibility, and resistance to wrinkles and shrinking, PET-based textiles provide a durable and comfortable alternative to traditional materials. The use of PET in textiles also contributes to the reduction of petroleum-based resources in the textile industry.

What is PP Plastic

Polypropylene, commonly known as PP plastic, is a widely used polymer with various applications across various industries. This thermoplastic polymer is derived from propylene monomers and is recognized for its exceptional durability, heat resistance, and chemical inertness.

One of the key attributes of PP plastic is its robustness, making it suitable for a range of products, from packaging materials to automotive components. Its high tensile strength and resistance to fatigue make it an ideal choice for applications that demand longevity and reliability. Moreover, PP plastic exhibits excellent resistance to acids, bases, and many organic solvents, enhancing its usability in diverse environments.

PET vs PP Plastic

The lightweight nature of PP plastic, coupled with its ability to withstand high temperatures without deformation, makes it a preferred material for manufacturing containers, caps, and closures in the packaging industry. Additionally, its low cost of production contributes to its popularity in mass-produced items.

In the automotive sector, PP plastic is extensively employed for manufacturing interior components such as dashboards, door panels, and trims. Its resilience to extreme temperatures and impact resistance enhance the safety and longevity of these components. Furthermore, the recyclability of PP plastic aligns with the growing emphasis on sustainability in manufacturing processes.

While PP plastic offers numerous advantages, it is not without its challenges. Limited resistance to UV radiation can result in degradation over time when exposed to sunlight, necessitating the addition of stabilizers in certain applications. Additionally, the recycling process for PP plastic can be complex due to variations in its chemical composition.

Similarities Between PET and PP Plastic

  • PET and PP plastic are both thermoplastics.
  • They are recyclable.
  • They are known for their durability and resistance to moisture, chemicals, and impact.

Difference Between PET and PP Plastic


PET (Polyethylene Terephthalate) is a thermoplastic polymer made from repeating units of ethylene terephthalate, while PP (Polypropylene) is another thermoplastic polymer, but it is derived from propylene.


PET is formed through the polymerization of terephthalic acid and ethylene glycol, while PP is produced by the polymerization of propylene.


PP is generally less transparent than PET.


PET is considered more versatile and adaptable than PP, especially when working with intricate designs.

Temperature Resistance

PET can withstand fill temperatures up to 160 degrees Fahrenheit, while PP can handle temperatures up to 176 degrees Fahrenheit.

Impact Resistance

Moreover, PET plastic exhibits higher durability and impact resistance compared to PP.

FAQ: PET and PP Plastic

Why is PET better than PP?

In terms of impact resistance, PET plastic cups are slightly better than PP containers.

Is PP more expensive than PET?

Yes, PP is more expensive than PET.

What is the difference between PP and PET labels?

PP labels tend to crease and stretch slightly, in comparison to PET labels.


PET and PP are two types of plastic polymers with distinct features. The main difference between PET and PP plastic is that PET is formed through the polymerization of terephthalic acid and ethylene glycol, while PP is produced by the polymerization of propylene.


1. “Polyethylene Terephthalate.” Wikipedia. Wikipedia Foundation.
2. “Polypropylene.” Wikipedia. Wikipedia Foundation.

Image Courtesy:

1. “Polypropylen” By NEUROtiker – Own work (Public Domain) via Commons Wikimedia
2. “Polyethyleneterephthalate” By Schippmeister – Own work (CC BY-SA 4.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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