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Is Polystyrene Biodegradable or Recyclable?

Updated: Nov 16, 2023

Written by Aaron Huang

Is styrofoam Biodegradable or Recyclable

Whether it’s to-go food packaging, lightweight cushioning for fragile deliveries, or insulation in your home, we’ve all seen plastic foam in action, one way or another. Polystyrene - the polymer from which plastic foam is made - is one of the most popular commodity plastics, but there’s no question about its negative impact on our environment. We’ve seen it washed up on the shore, floating along river beds, and blowing through the air. In 2020 the U.S. alone generated 292 million tons of municipal solid waste, of which 69 million tons were recycled and 25 million tons composted. One hundred forty-six million tons ended up in landfills, 30% of which was EPS.

There’s plenty of clutter online around the global waste crisis. Whether you’re reducing plastic, recycling relevant materials, or opting for biodegradable polystyrene foam alternatives, it can be challenging to determine the right thing to do.

Perhaps one of the most significant avenues for misinformation is biodegradable packaging materials, particularly when it comes to polystyrene foam. That’s why we’ve put together a comprehensive guide outlining what you need to know to make informed choices in the future. Better yet, we unpack the all-important question, “Is polystyrene biodegradable at all?”

What exactly is plastic foam?

Plastic foam is a form of polystyrene. By definition, polystyrene is a transparent, amorphous, non-polar commodity thermoplastic. It’s often turned into foams, films, and sheets because it’s easy to process. On the upside, polystyrene foam has excellent resistance to diluted acids and bases, you can mold it with ease, and it delivers optical clarity. On the downside, it has poor oxygen and UV resistance, and it’s brittle, giving low impact to strength.

Plastic foam is considered a type of Expanded Polystyrene (EPS) consisting of micro-beads containing pentane. This foamed version of polystyrene boasts high impact resistance, excellent processability, low weight, and thermal insulation. This is why we use it to create disposable drinking cups, trays, fast-food containers, and cushioning for various packaged goods. It’s also why you’ve probably seen EPS foam insulation in buildings or packaging.

Polystyrene vs Styrofoam

Polystyrene and Styrofoam are two materials that are often used interchangeably, but they are not exactly the same. While they are made from the same basic material, there are significant differences in their properties, uses, and production processes.

Polystyrene is a versatile plastic polymer that is widely used in a variety of industries. It is a hard, brittle plastic that is easily molded into different products, shapes, and foam materials. It is used for a range of applications, including packaging, electronics, toys, and food service items. Polystyrene is made from styrene monomers, which are derived from petroleum.

Styrofoam is a brand of expanded polystyrene foam that is commonly used for insulation and packaging. The foam is produced by heating and expanding tiny beads of polystyrene with steam. The resulting foam is lightweight, strong, and has excellent insulating properties. It is commonly used in construction applications, a favorite being Styrofoam construction insulation foam.

What Does It Mean For Something To Be Biodegradable?

There’s no question about the improved awareness of the detrimental impact of plastic on the environment. Environmentally friendly alternatives have emerged, with more and more countries banning single-use plastic. Plus, mainstream media paints the picture of “biodegradable” products as the ultimate “green” alternatives.

While it is progress that plastic waste awareness is something to get excited about, it’s essential to understand some myths around biodegradable packaging, especially regarding polystyrene, aka plastic foam, EPS, or EPE.

By definition, biodegradation is the breakdown of organic matter by microorganisms like bacteria and fungi with the help of sunlight, moisture, and other natural processes. It means it can disintegrate or decompose by slowly breaking down into smaller pieces that are essentially unseen. In essence, if something is “biodegradable,” people believe that you can throw it away without causing any harm.

While some biodegradable plastics can be broken down by microbes and turned into biomass, water, and carbon dioxide, the large majority of plastics, including plastic foam or polystyrene, break down into microplastics which are extremely dangerous. Only a minority of the plastics we interact with are bio-benign. While this seems a bit confusing, it is critical to understand the distinction so that we make the right choices. Let’s unpack it in more detail.

Is Polystyrene Biodegradable?

In short, no, it’s not. It may break down, but it doesn’t disappear.

Technically, biodegradable polystyrene foam can break down to a point where you can no longer see it with the naked eye. Polystyrene can degrade by two mechanisms: photodegradation and mechanical degradation.

Photodegradation is the breakdown of polymers due to exposure to sunlight, which leads to the formation of smaller molecules. However, this process is slow and requires prolonged exposure to sunlight.

Mechanical degradation occurs when polystyrene is broken down into smaller pieces by physical forces, such as wind, waves, and currents. Over time, these smaller pieces can become microplastics, which are less than 5mm in size. Microplastics can accumulate in the environment and cause harm to marine and terrestrial organisms.

Polystyrene goes through photodegradation when it reaches 30º Celsius, similar to seawater temperatures in places like Malaysia or along the U.S. Pacific Coast.

Water samples collected from this region revealed alarmingly high levels of styrene monomer, styrene dimers, and styrene trimers, all of which are polystyrene foam products. These eye-opening findings were published in an article from ScienceNews, unpacking the dire effects of styrene monomer in particular. It’s classified as genotoxic and carcinogenic, contributing to diseases like cancer.

More recently, scientists have uncovered microplastics from biodegradable polyester in seawater and freshwater. Sunlight promotes microplastic formation meaning biodegradable plastics made from wood pulp and corn actually produce more microplastics than non-biodegradable polymers.

Microplastics are a significant environmental concern, and the presence of microplastics in the environment is widespread. They can be ingested by marine organisms, such as fish and turtles, or on land. A build-up of microplastics in the digestive system causes blockages, sometimes resulting in death.

Additionally, microplastics can accumulate toxins, such as persistent organic pollutants, and transport them through the food chain, leading to potential health risks for humans as well as animals.

Can You Recycle Polystyrene?

Polystyrene is notorious for its negative impact on the environment due to its lack of biodegradation along with its difficulty in recycling. In fact, recycling polystyrene can be quite challenging for several reasons. Here are the top five.


  1. It’s not easy to recycle polystyrene foams

If you’re looking to recycle polystyrene foam at home, there are a few things you need to wrap your head around. Most importantly, there are different forms of plastic foam, and only some of them are recyclable.

The plastic foam must be made with Expanded Polystyrene. Recycling facilities won’t accept any other types of polystyrene. Unfortunately, most polystyrene foam containers you get with to-go food fall into this category. Thanks to the dye contaminating the process, you will also struggle to recycle colored polystyrene foam.

If you are looking to recycle polystyrene foam, look for the correct code. The EPS number is 6, and you’ll need to ensure you remove any stickers, sellotape, or dirt before taking it to your closest facility, and only if they accept it.


2. It’s expensive


While some plastic foams can be recycled, it’s unlikely that all local plants have the necessary equipment. More often than not, it’s transported to a centralized plant, making it an incredibly costly exercise. It means that many recycling companies run at a loss, making them less incentivized to push for polystyrene foam products.


3. You can’t use recycled plastic foam In the food industry


In most cases, recycled plastic foam or polystyrene can’t be used for products in contact with food. Why? There are growing health concerns around the material itself. Although it’s sterilized during the recycling process, it’s often used to create packaging for other materials. You’re always going to need new EPS for food packaging, inevitably reversing any positive impact the recycling process has on the system as a whole.


4. Lack of demand


The lack of demand for recycled polystyrene is a major obstacle to its widespread recycling. While polystyrene can technically be recycled, there are few markets for recycled polystyrene products, which makes it difficult for recycling facilities to justify the expense of processing it.

Can you compost polystyrene foam?

Some plastics are compostable, meaning microbes break them down into compost, similar to food waste. Again, this doesn’t eliminate those microplastics that riddle our soil and water.

Composting polystyrene foam is not recommended. Given that it’s not biodegradable, it will not break down properly in a compost pile. Additionally, adding polystyrene foam to your compost can actually contaminate the entire mixture, making it unusable for gardening or other purposes.

Compostable Solutions Are The Future

That’s where sustainable materials companies such as Cruz Foam come in. By prioritizing return to earth-friendly materials, Cruz Foam has created the ideal compostable foam packaging to replace polystyrene foam altogether. Natural bio-benign foam solutions are the epitome of packaging made by nature, dissolved by nature. Unlike other protective packaging materials, Cruz Foam has no adverse effects on the soil quality after the degradation process. Better yet, it produces high-quality organic waste, which can be used as fertilizer.

Want to find out how we can help you make your business more sustainable? Contact Cruz Foam today.






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