What is difference between polyethylene and polypropylene?

Polypropylene addition or condensation

Polypropylene and polyethylene are two very similar plastics that are often difficult to distinguish. However, each of them has specific and well-defined functions. As we have almost 200 products of these materials in the Rajapack catalog, we have prepared this article in which we will reveal the main differences between the two and you will be able to choose which material you need.

Polyethylene is the most widely used plastic in the world. It is also one of the cheapest materials available. It resists low temperatures better than polypropylene, is more flexible and has high resistance to abrasion, impact and wear. Between -80° and 80° it holds up perfectly. It is easy to stretch. Due to its low price, it is the main product from which plastic bags and safety foam are made.

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Which is better: polypropylene or plastic?

Its main characteristics are a great resistance to traction (breakage). It withstands more kg/m than any other fiber, and a great resistance to solar incidence and abrasion by friction. On the other hand, it has a higher water absorption level than other materials and its resistance in chlorinated environments is weakened. It is heavier than water (it sinks) and of the three fibers compared, it is the most resistant to sunlight and climatic changes. It has a textile appearance and is ideal for outdoor use.

Polyethylene is a synthetic fiber with a plastic feel. Its main characteristics are very low water absorption, good resistance to chlorinated environments (swimming pools) and good resistance to climatic changes. On the other hand, its tensile strength is medium and it is not designed for load-bearing applications. It is plastic in appearance and of the three fibers compared it is the most difficult to handle, it weighs little (it floats). It is very resistant to abrasion but its resistance to the sun is average.

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Polyethylene vs. polypropylene

Polyethylene or polyethylene is also a polymer, but it is made of an ethylene monomer. It has a chemical formula of (C 2 H 4 ) n . The first synthesis of this occurred as an accident in 1898 by the German scientist Hans von Pechmann. Like PP, it is also a thermoplastic by its very nature. Its abbreviated form is PE. PE ranks first as the most widely used plastic worldwide. However, not all plastics are PE. Polyethylene is not easily malleable because it is very stable. It is a good electrical insulator. It has a very low melting point and is used massively in the automotive industry as well as in the food packaging industry. Approximately 70 percent is used in food packaging, food containers, pallets and even boxes and bottles.

Polyethylene vs. polypropylene bags

All these characteristics make polypropylene and polyethylene materials widely used in the packaging world, as well as in other sectors such as toy, DIY or automotive.

Some of the most commonly used products for interior packaging and manufactured with polyethylene are polyethylene plastic bags, which include those used in stores, as well as those used for shipping and even garbage bags. Also widely used are stretch film, bubble wrap, protective foam sheets or plastic boxes with grids.

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Some of the products made with polypropylene and frequently used in the packaging world are adhesive tapes, strapping used to seal pallets and boxes and plastic boxes and crates used for product storage, which, given the consistency that polypropylene gives them, offer many advantages such as being stackable, a feature much appreciated in the field of logistics and warehouse management.