Bioplastics

By Anna Johnson, GCC 3011 student

Many of the things we eat, and drink come in single use plastic containers. Of all the plastic thrown out in the U.S. in 2018, only about 9% of it was recycled. That’s why some companies are trying a new approach, biodegradable containers. Mars Wrigley is leading the way in taking responsibility for the products they produce; they assume you will litter the wrapper before recycling it. Because of this, they have partnered with Danimer Scientific to make a biodegradable wrapper sourced from canola and soy seeds. They also plan to have all packaging reusable, recyclable, or compostable by 2025. Following suit, Bacardi has pledged to be plastic free by 2030. They recently revealed a fully biodegradable plastic bottle made from plant-based oils that will break down within 18 months. However, with all these exciting new developments there are always caveats.

First, let’s discuss the two main types of bioplastics that are used, polylactic acid (PLA) and polyhyroxyalkanoate (PHA). PLA is a process that transforms corn into plastic. The corn is first submerged in sulfur dioxide and hot water to break down the components, later citric acids are added to make the long-chain polymer that is the building block of regular plastic. PHA is made by microorganisms that produce plastic from organic materials. PHA is often used for bone plates, skin substitutes and single-use food packaging because it’s biodegradable and doesn’t harm living tissue. 

Now let’s talk about the potential problems that come with producing bioplastics. Even though bioplastics are thought to be more eco-friendly, some studies indicate that might not be the case when the life cycle of the product was taken into account. Some research suggests that bioplastic production resulted in more pollutants. Some of those pollutants come from fertilizers and pesticides used to grow plants and the chemical processes used to convert the plants to plastic. Other studies suggest that switching to bioplastics could cut greenhouse emissions by 25% in the U.S. Before adopting bioplastics, there needs to be awareness that they must be disposed of properly. If bioplastics contaminate recycled PET (used for water and soda bottles) the whole lot could be rejected from the recycling plant and tossed into a landfill. 

Another bioplastic option available are polyhydroxybutyrates (PHB). They are a bioplastic made from polyester. PHB require less energy when the energy of production and feedstocks are figured into the total. The entire life cycle energy needed for PHB are 44.7 MJ per Kg plastic produced. That can be compared to PLA which has an energy requirement of 54.1 MJ per Kg plastic produced. Petropolymers require 81.8-85.9 MJ per Kg plastic produced. That means bioplastics could significantly improve energy savings in the future. If all U.S. petropolymers switched to PHB or PLA, the yearly energy savings would be 363 and 280 PJ. 

All in all, bioproducts are a great investment for the future of plastics. Although, there need to be some adaptations made to the processes they go through to make them more eco-friendly. Bioproducts are healthier for humans to use as food storage when compared to regular plastics. 

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