Differences between polyethylene and polypropylene

Polyethylene or PE plastic and polypropylene or PP plastic are two polymers derived from petroleum that are very present in our daily lives, and have similar characteristics, making them difficult to differentiate. Therefore, in today’s article, we explain the main differences between polyethylene and polypropylene. Find out everything you need to know here.

Characteristics of polyethylene

Polyethylene is a polymer used worldwide to make most of the plastic products that surround us (plastic bags, detergent containers, gel, cleaning products, etc.).

 Although it is a polymer of ethylene, there are also variations in the chemical structure of this polymer, giving rise to different types of polyethylene, with different properties (such as linear or branched polyethylene, for example). In turn, there will be differences in the number of branches and length of the chains. This is why we find low density or very low density polyethylene and high density or very high density polyethylene.

In terms of its uses, we can see it in plastic bags, paper fil, protective helmets or plastic for packaging.

Characteristics of polypropylene

Polypropylene is another of the most widely used plastics. It is lightweight and offers high resistance to high temperatures and chemicals such as acids and solvents.

Polypropylene can also be modified in its manufacture in terms of the arrangement of the monomers (propylene) during polymerisation, as well as being a copolymer. This will result in products with different properties and adapted for different uses.

Its uses range from adhesive tapes or packaging to automotive parts or packaging.

Differences between polypropylene and polyethylene

Both PP plastic and PE plastic are two polymers with similar characteristics and functions, so it is sometimes difficult to distinguish between them. However, each is different as they have a different chemical composition, which results in different properties and applications.

The main differences between the two are as follows:

1. Polypropylene is lighter than polyethylene and also less flexible, making it more difficult to break.
2. Polypropylene is more resistant to high temperatures (it remains in perfect condition up to 100ºC), abrasive agents and chemicals.
3. Polyethylene, however, is more resistant to low temperatures.
4. Polyethylene offers high durability and is more economical than polypropylene.
5. Polyethylene is used much more frequently than polypropylene, as the simplicity of its composition means that it is used in the manufacture of most types of polymers.

Similarities of PP plastic and PE plastic

As mentioned above, these polymers have their differences because of their different compositions. But they also have certain similarities because they are both used in the manufacture of plastic:

1. Both can be coloured very easily.
2. They are materials that can withstand stretching effectively, which is why they are widely used in the world of packaging.
3. They are very versatile and malleable plastics. That is why they are present in different sectors and formats: DIY, automotive, toy sector…
4. Both are cheap, but it is important to remember that both are recyclable plastics and as such are labelled in their production process.

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