Why Bioplastics

The Importance Of Sustainability

Sustainable bioplastics play a critical role in shifting society towards a sustainable "circular" plastics economy. Conventional plastics derived from petroleum cause harm to the planet due to the consumption of non-renewable resources, net positive carbon emissions, and creation of recalcitrant waste.
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Sustainable bioplastics include materials derived from natural biomass or produced by biological systems. Bioplastics are a better alternative to petroleum-based plastics and provide many benefits to the environment. For example, many bioplastics are derived from plant biomass, which means that the CO₂ emissions caused by manufacturing can be offset by the CO₂ absorbed during plant growth. Some bioplastics can also naturally biodegrade into building blocks that can be used by natural organisms, which prevents long-term waste accumulation. Thus, the adoption of sustainable bioplastics will make a positive impact on our future.

The Circular Economy And Closing The Loop

The term “circular economy” refers to the ability of a product to re-enter an economic supply chain post end-of-life. However, most plastics usage today follows a linear economy. For example, only about 14% of plastic packaging items are collected for recycling, while the rest are sent to landfills, incineration plants, or leak into the environment. From that amount, 8% is sent to cascaded recycling, where they are turned into lower-value products, and only 2% is maintained in a closed loop, where it can be continuously reused or recycled into a product of similar quality (MacArthur Foundation, 2020). Virgin feedstock must be continuously added to create new plastic materials. The cost of this is extremely massive: every year, an estimated $2.2 trillion USD is lost to plastic pollution (Frontiers, 2019), and that number continues to grow.

Development and use of bioplastics can help close the loop for the plastics economy. By replacing conventional plastics with bioplastics, the use of non-renewable petroleum-based virgin feedstock can be reduced. Furthermore, biodegradable bioplastics can be used to generate benign, high value products at their end-of-life rather than contributing to accumulating plastic waste in the environment.

Types of Bioplastics

Bioplastics Are Diverse

There are many ways to classify bioplastics. However, there are three main groups: bio-based plastics, biodegradable plastics, and plastics that fall under both categories.

Bio-based plastics are partially or fully derived from plant/fungi biomass (e.g. corn, algae, mycelium) or from animals (e.g. silk, collagen). Some examples of commercially available bio-based plastics include bio-polyethylene tetraphthalate (bioPET), bio-polyethylene (bioPE), and bio-polytrimethylene tetraphthalate (bioPTT). While bio-based plastics do not use non-renewable petroleum-based resources, they are not necessarily biodegradable, meaning that they can still potentially accumulate as waste in the environment.

‍Biodegradable plastics can be broken down by biological organisms, such as bacteria or fungi. In some cases, this degradation process can be used create useful products, such as compost or commodity chemicals. Biodegradable plastics are not necessarily bio-based. For example, polybutylene adipate terephthalate (PBAT) and polycaprolactone (PCL) are biodegradable but are made from petroleum-based resources.

Plastics that are both bio-based and biodegradable are highly desirable, as they are made using renewable resources and can also naturally break down in the environment. Examples of bio-based biodegradable plastics include polyhydroxyalkanoates (PHA), starch-based plastics, and silk.

Current State of Bioplastics

Quite a few bioplastics are designed as drop-in replacements for conventional plastics (meaning they are chemically identical to its petroleum-derived counterpart). Example drop-in replacements include bioPE and bioPET. These drop-in replacements are not naturally biodegradable but are more readily implemented in existing products and manufacturing lines.

Some bioplastics, especially naturally derived materials, such as polysaccharides and proteins, differ substantially in chemical structure from conventional petroleum-derived plastics. While many of these bioplastics have drastically different properties than petroleum-derived plastics, some naturally produced bioplastics, such as PHAs, can potentially be used to replace conventional plastics with minimal changes to the product design and manufacturing process. Regardless of whether their properties match those of conventionally used plastics, naturally derived bioplastics have the advantage of being biodegradable in the environment.

Source: European Bioplastics, nova-Institute (2023)

Approximately 50% of bioplastics produced in 2023 are biodegradable. The remaining 50% is not biodegradable but are considered bioplastics because they are made with renewable biomass. Over time, the proportion of bioplastics that are biodegradable will likely increase.