Packaging Advice

Polystyrene vs Polyethylene: Defining the similarities and differences

3 mins

Impact resistant, lightweight, and available in many forms, there is no wonder that polystyrene and polyethylene are some of the most used polymers for protective packaging today. However, it can be easy to mix these two polymers up, so it is important to establish the key differences between them and how they can be used.

In this article, we look closer at the properties of both thermoplastics and see what makes them unique.

Polyethylene packaging

As the most chemically simple polymer, polyethylene is comprised of only carbon and hydrogen. It is highly resistant to chemicals, UV Light, and moisture and can be melted, reformed, and cooled into different shapes. This not only makes the polymer suitable for pharmaceutical packaging, but also makes it a significantly more sustainable packaging solution when compared to polystyrene, due to it being reusable and non-toxic. As polyethylene has all the necessary properties for continued reuse, it minimizes the environmental footprint for every package shipped.

Polyethylene also has durability and capacity to absorb multiple impacts, and multi-impact cushioning protection is crucial in e-commerce where transit shipments are long. Therefore, not only is it ideal for home improvement retailers, but it is also exceptionally popular within the food and drinks packaging industry, due to it being so versatile and considered food safe by the FDA.

Additionally, with the increased concerns in hygiene, polyethylene is an easy material to clean as most household cleaners can be used on polyethylene without causing any damage.

Polystyrene packaging

Unlike polyethylene, polystyrene is a single-impact cushion material, meaning it cannot be re-used for packaging material. However, it can still be recycled provided it is disposed of properly and it is most used within customised or bespoke packaging to encase objects.

The three different forms of polystyrene are:

  • Polystyrene foam: the most common type, this includes expanded polystyrene and extruded polystyrene. The expanded type being the most used for everyday applications and extruded being much more dense and durable and used for larger applications.
  • Polystyrene plastic: This type of polystyrene is highly impact resistant, especially when combined with other materials. Therefore, it is most often used in protective applications such as windows and screens for electronic devices.
  • Polystyrene film: Used in a variety of packaging purposes, polystyrene film can be vacuum formed, stretched out over a product and sealed to prevent air from leaking out or entering.

 As polystyrene is also a thermoplastic which begins to melt at around 210 degrees celsius. Once melted, it can be reshaped into new forms then cooled until solid, which is similar to polyethylene.  It is also one of the most cost-effective plastics out there and is very easy to cut it into shapes using two-dimensional shaping, computer guided cutting or even household tools. Therefore, this type of packaging is commonly used by engineers for automotive or electronic packaging.

While it is true that Polyethylene and polystyrene have many similarities, they do have a few clear differences. For example, while polyethylene is much more resistant and durable in HDPE and UHME forms making it more practical for construction packaging, polystyrene is easily shaped and formed, so this makes it more ideal for engineering packaging purposes than polyethylene.

The polymer your business uses depends on whether you require packaging to be more eco-friendly and reusable such as polyethylene, that can protect your products during long transits, or if you are looking for packaging that would be the best at protecting your electrical products, which would be polystyrene. For the best polymer fit for your company, please get in touch with our packaging experts today to learn more.