Biopolyethylene — A Better, But Far From Perfect Alternative to Polyethylene

Polyethylene is the most widely produced plastic in the world, primarily used for plastic bottles, bags and films. Over 60 million tonnes are produced every year. Biopolyethylene is a biobased alternative that is becoming commonly utilized in the cosmetics industry and can be obtained from sugar cane, sugar beet, and wheat grain as opposed to petroleum. This is much better for the environment in a variety of ways, as the plastic retains identical properties to its counterpart while alleviating the need for fossil fuels. Why, then, has biopolyethylene not fully replaced regular polyethylene?

The Problem With Polyethylene

Polyethylene is a lightweight and durable thermoplastic that, like PET, is technically considered safe because it contains no BPA. However, polyethylene leaches a toxic chemical called antimony, a metalloid that can cause vomiting, stomach ulcers, and diarrhea. Polyethylene is commonly used in food handling but can be harmful if inhaled and is particularly dangerous to juveniles and fetuses. It can be recycled but is not biodegradable, leading to numerous environmental issues. Having a biodegradable alternative would be very useful.

Polyethylene is produced from its basic monomer ethylene. First, ethane is extracted from petroleum or natural gas. Ethane is then turned to ethylene through a heating process which then compounds when treated with chemicals into polyethylene. Now, though, scientists are looking into drawing ethylene from renewable sources, which is, as you may have guessed, called biopolyethylene.

How is it made?

Polyethylene is produced through polymerization by deriving ethane from a process like crude oil distillation. Biopolyethylene is made in the same way but instead utilizes ethanol made from the fermentation of biomass, which is a clear, colourless alcohol nearly identical to ethylene and made from feedstocks. This can then be converted to ethylene after dehydration, and polymerization added to make the ethylene into biopolyethylene.

Breaking that down ⬇

Ethane from fossil fuels ➡️ Ethylene ➡️ Polyethylene

Ethanol from biomass fermentation ➡️ Ethylene ➡️ Biopolyethylene

Biopolyethylene as an outcome has properties identical to those of regular polyethylene, both physically and in terms of 100% recyclability applications.

Benefits

The first obvious advantage of biopolyethylene is that, by reducing petroleum use, there is a decrease in environmental damage. Furthermore, during growth, feedstock sequesters CO2, achieving a net reduction. Lastly, biopolyethylene is easy to scale, because it can be a drop-in replacement for traditional polyethylene within tubes, storage bags, packaging films, and more.

Downsides

A huge problem with biobased plastics as a whole is that they could heavily contribute to deforestation and land clearing because production is directly reliant on intensive agriculture. If rainforests, peatland, and grasslands had to be converted to agriculture for crop growth, this would emit enormous net CO2 emissions. It’s also a fairly large portion of our food supply gone, and the influence climate change is having on farming in tropical areas is only going to make this less plausible.

There’s also the point of creating the biopolyethylene not being completely carbon neutral — although it doesn’t use oil in the manufacturing process, the energy used in production would likely use an input of fossil fuels, fertilizers, or pesticides. The carbon output will be reduced, but not zero.

TL;DR

Let’s do an overview of what we went over!

• Polyethylene is one of the most commonly used types of plastics today but has severe negative impacts, leaching a toxic chemical called antimony which can be harmful to both humans and the environment
• Biopolyethylene is a biobased alternative that retains the exact same properties as its counterpart
• Polyethylene is made by deriving ethane from fossil fuels, which is then turned into ethylene through heating; biopolyethylene is produced the same way but with a starter substance of ethanol from biomass
• Advantages include environmental benefits, sequestration of CO2, and scalability
• Disadvantages include intensive agriculture and the likely input of fossil fuels

Thank you so much for reading this! I’m a 15-year-old passionate about sustainability, and am the author of “Chronicles of Illusions: The Blue Wild”. If you want to see more of my work, connect with me on LinkedIn, Twitter, or subscribe to my monthly newsletter!