4 Polyethylene Types and Their Applications

Plastic polymers are widely opted for as they have various properties, which make them a suitable choice for different applications. Polyethylene (PE) is a thermoplastic that has widespread uses and is opted for in many industries.

If you are looking to learn about polyethylene types and want to use it in your applications, read the guide below.

What is Polyethylene (PE)?

Polyethylene is a type of homopolymer that has ethene chains of molecules. The chemical structure of this material is the same as plastic, but it is used for versatile applications. It could be used for a jar in your kitchen and, at the same time, proves to be a suitable choice for knee replacement parts.

A Brief History of Polyethylene Plastic

The invention of polyethylene was done in the 1930s when Eric Fawcett and Reginald Gibson conducted an experiment using benzaldehyde and ethylene, which led to polyethylene.

After a few years, in 1936, Imperial Chemical Industries created a patent for the material, and its adaptability led to multiple uses. After that, another chemist named Carl Ziedler figured out HDPE, which is a type of polyethylene.

How Polyethylene is Made?

Polyéthylène is made from ethylene originating from natural gas and crude oil. Ethylene requires a catalyst to be converted into polyethylene.

The process of polymerization of polyethylene is known as addition polymerization and is also called chain reaction polymerization. The catalyst is introduced, which makes the monomers react and form chains; such a reaction forms the plastic.

Another polymerization process, named free radical polymerization, uses a radical which breaks the double bond between carbon atoms. In the reaction, one of the sides of the molecule is left open for bonding and can easily slide and link to create a chain of polymers.

The polymer can be shaped in filaments and cut into pellets which make them convert into different objects after processing.

Pros and Cons of Polyethylene (PE)

Polyethylene (PE) has some pros and cons, and these are as follows:

Pour

• PE is highly resistant to wear, impact, and environmental stress and doesn't crack easily.
• It has the ability to withstand the exposure to various chemicals.
• PE is lightweight and can be opted for applications where weight is a concern.
• It is economical when compared to other types of plastics.
• It has a wide range of grades, which makes it suitable for many applications.

Cons

• Polyethylene becomes brittle when subjected to cold temperatures.
• It has limited stability against UV and degrades over time when subjected to sunlight in the long run.
• It has a nonstick surface, which makes adhesion and painting challenging.
• It is flammable and ignites easily.
• It is non-recyclable and hence may cause environmental concerns.

Polyethylene Types

There are four different types of polyethylene, and these are discussed below:

Ultra-High Molecular Weight Polyethylene (UHMWPE)

Ultra-high molecular weight polyethylene is a tough form of PE which is capable of withstanding high wear and tear. It also has a low coefficient of friction and can be used in many industrial applications. It mostly opted for components like rollers, gears, bushings, and bearings manufactured using CNC machining.

High-Density Polyethylene (HDPE)

HDPE is a common type of polyethylene that is highly flexible and is chosen for pipes and plastic bottles. It is highly suitable for strong structures, and the best part is that it can be recycled. HDPE components can be manufactured during injection molding as well as Usinage CNC.

Low-Density Polyethylene (LDPE)

LDPE is a clear and transparent type of polyethylene that is very soft. It has a low crystalline nature and is not complex; rather, it is flexible. It is mostly opted-in products like fittings, bottles, and food containers manufactured through injection molding.

Linear Low-Density Polyethylene (LLDPE)

LLDPE is very similar to LDPE and is very soft and flexible. It has an open-branched structure of molecules. However, it can stretch and, at the same time, offer excellent tensile strength. It is mostly selected for stretch films used in many industries.

The Properties of Polyethylene

Polyethylene has various properties, some of which are as follows:

• It offers a high electrical strength and is rigid.
• Polyethylene offers ductility, which makes it suitable for many applications, and at the same time has a high impact strength.
• The texture of polyethylene is waxy, and when subjected to force, it possesses a strong creep.
• The melting point of its grades, like HDPE, is between the range of 120 to 180 degrees centigrade. In contrast, the LDPE has a melting point of 105 to 115 degrees centigrade.
• Polyethylene is an excellent conductor of electricity.

Applications du polyéthylène

Polyethylene has versatile applications ranging from day-to-day products to heavy-duty applications, and some of these are given below:

• Food containers
• Implants médicaux
• Fishing nets
• PE bags
• Pipe fittings and pipes
• Water tanks
• Bottles
• Cordes

Conclusion

Polyethylene (PE) is one of the most common materials used in many applications. If you are inclined to use it for your components and want to have it processed using CNC machining and injection molding, contact us at DEK. We offer high-quality components customized for your projects with excellent finish and durability.