Why Is Plastic So Hard To Recycle? (And How We Can Combat Plastic Waste)

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Plastic is not really "broken down" it's downcycled in many situations. (Image: Texas Standard)
Plastic is not really "broken down" it's downcycled in many situations. (Image: Texas Standard)

Circularity Fast Facts: The Big Picture of Plastic Recycling

  1. Plastic is a relatively recent phenomenon → Half of all plastics ever made have been produced since 2005 (1).
  2. Single-use plastic packaging in particular is a big problem → nearly 50% of plastic waste generated globally in 2015 was [single use] plastic packaging (2).
  3. No surprise here: We make an incredible amount of plastic → 360 Million tons of plastic was produced worldwide in 2018 (3).
  4. However, very little of that “incredible amount of plastic” is ever recycled → Only 9% of plastic ever made has been recycled. (4).
  5. Due to China’s Plastic Ban in 2017, countries are largely left to contend with the waste themselves → Before the ban, the US exported about 70% of our plastic waste to China (5)

Plastic is ubiquitous, yet so little of it is recycled. Why?

Plastic isn’t the only thing we recycle. Glass, paper and aluminum can all be recycled. So why do we only hear about issues with plastic? There are several reasons plastic is the problem child of recycling.

Stability

Plastic is very stable. I’m not talking about stable as in a relationship, looking at you Oprah and Stedman. I’m talking about chemically stable.

Think about it this way, whales, camels and fish have all been found with plastic in their stomach. This means even stomach acid has trouble breaking down plastic! Plastic’s robust nature comes from its chemical structure of long molecular chains, called polymers. It is exactly this chemical robustness which makes plastic a blessing and a curse. Plastic is an incredible material with almost infinite uses in our everyday lives but its stability makes it challenging, if not, impossible to recycle.

To explain this more, let’s dive into the two main types of plastics starting with thermoplastics. Thermoplastics will melt under heat, hence the name thermo. Examples of thermoplastics are grocery bags, plastic water bottles, and all other “1 to 7” category plastics. A thermoplastic will behave similarly to butter in a hot pan; it melts. Thermosets, on the other hand, become stronger with heat. A thermoset is more like an egg in a pan; it hardens with heat and once it is cooked, it cannot go back to its former state. Examples of thermosets are computer keyboards and parts in aerospace and automobile applications.

There are challenges with both thermoplastics and thermosets when it comes to recycling due to their chemical stability.

Plastic is almost never truly "recycled."

Very rarely can plastic truly be recycled and this is due to the chemical stability of the long molecular chains we talked about earlier. You can imagine the chemical structure of a thermoplastic like a long chain of people holding hands.

When a thermoplastic is recycled, it is traditionally heated to break it down. And it does exactly that, it breaks down the molecular chains (imagine several of these people drop their hold on each other). This makes the plastic weaker.

That’s why thermoplastics cannot be “recycled” (a plastic water bottle makes another plastic water bottle). Instead, they are typically “downcycled” (made into another product) or thrown in the landfill or ocean. Thermoset plastics, on the other hand, cannot be melted at all because they become stronger with heat (like the egg in the pan). There are few end of life options for these plastics so they are simply broken down into smaller pieces or thrown in the landfill.

Wish-cycling

We talked about why plastics are physically difficult to recycle but what about the consumer’s role in recycling?

You may have heard this term wish-cycling. It means throwing something in the recycling bin in the hope it will be recycled but in reality it cannot be. Recycling, like all other manufacturing, is an industry. It requires profit and labor and resources to operate. When things are put in the recycling bin that cannot truly be recycled (some typical items would be plastic utensils, plastic grocery bags or ziplock bags) it slows down the entire recycling process sometimes forcing the hauler to throw away the entire load of recycling because it is not worth their time to sort out the contamination.

This means that when we recycle something that cannot be recycled, the entire load of material is jeopardized.

So what can we do?

I am of the opinion that plastic itself is not the enemy, but rather the way we think about plastic.

Plastic’s chemical stability makes it an incredible material for applications where we need such a dependable and robust material, such as in the aerospace or automobile industry. But when we use this remarkably stable material for a single use it makes me feel, to quote Mugatu in Zoolander, “like I’m taking crazy pills.” There is no reason to use a material which is so robust for a single use. In my mind, there are three things we need to do to shift our mindset around plastics:

  1. Create incentives for businesses and consumers to replace single use plastics with a material which will break down quickly (such as compostable materials).
  2. Invest in plastic recycling infrastructure and technologies.
    Research at MIT is being conducted on recycling for thermosets, Novoloop is a startup which created a low temperature chemical recycling alternative which maintains the mechanical qualities of plastics, BASF is using pyrolysis to convert plastic waste back into feedstock for their process and CleanRobotics and AMP Robotics are using AI to sort contamination out of recycling.
  3. Educate ourselves as consumers as to what can be truly recycled.
    Call up your waste hauler, ask them about their hopes and dreams and if they have any pets. Then ask them what can truly be recycled at their facility. Seriously, call them! By doing this, you are giving those recyclables the best chance they have at being recycled.


Plastic is a useful material thanks to its chemical stability. Let’s learn to treat it like something that will be around forever… because it will be.

About The Author

Oakley Jennings-Fast The Impact

Oakley Jennings-Fast

Independent Contributor

Oakley is a chemical engineer and started her career in chemical manufacturing at BASF. She is currently Director of Circular Economy at Smart Waste USA  where she enables companies to divert their landfill waste. She also founded a company called Level Up Planet where she consults businesses and educates individuals on circular economy and sustainability.

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