Discover
Bioplastics
Published November 30, 2021
There’s something about our nature that makes us demand convenience. Call it a need for efficiency, satisfaction; call it immediate gratification; call it the consumer’s priority.
Single-use plastic packaging unequivocally solves this demand for convenience. It lines itself among shelves in the freezer aisle with Minute Maid labels, enshrouds magazines across a United Dairy Farmers countertop. Ten minutes—no, let’s say five minutes—after a sleep-deprived college student buys a 12-pack of Clif Bars, she tears the wrapper asunder, and down it goes that chocolate chip delight. All is well, until you see the wrapper is still here.
What’s it still doing here?
Composition
Imagine a world where not only the demand for convenience is met, but the consequences for such a lofty feat cease to be; or, in the very least, fade out of existence.
This is the ideal world of the bioplastic era.
The definition of bioplastics varies widely across environmental organizations. Generally, though, a plastic-like material can be labeled as a bioplastic if it’s either biobased, biodegradable, or both.
One form of bioplastics is a biobased polymer, a material made from renewable biomass sources, such as vegetable fats and oils, corn starch, straw, woodchips, sawdust, and food waste.
Note
When something is biobased, it is made
from plants, animals, or both.
The other form of bioplastics is biodegradable plastic. These plastics are susceptible to degradation by biological activity. Be aware that biodegradable plastics are not biobased, and not all biobased polymers are biodegradable.
The Federal Trade Commission (FTC) regulates and enforces qualifications for labeling claims on bioplastic packaging. The most commonly used terms on bioplastic labeling are biodegradable, compostable, OXO-degradable, and photo-degradable.
Biodegradable means the entire item will completely decompose (into elements found in nature) in a solid waste stream within one year after customary disposal.
Compostable means the breaking down of a material into organic matter at the rate of cellulose. All parts of this material must disintegrate in the compost and must not leave behind any toxic residue.
OXO-degradable means the fragmenting of an item through oxidative methods only. Materials having this property cannot biodegrade or be composted.
Photo-degradable means the fragmenting of a material through the absorption of photons. The remaining fragments are small enough to be absorbed by microorganisms.
Note
When there are no microorganisms present, complete
mineralization of bioplastics is not achieved,
and only microplastics remain.
Importance
Theoretically, the carbon footprint of bioplastic production is lower than that of the production of conventional plastics. Furthermore, bioplastics are produced from sustainable materials such as wheat, starch, cellulose, hemp, kelp, and bamboo fibers.
The chart below presents the most common types of plastics in their respective categories:
Among all types of bioplastics, only a few are biobased and biodegradable, and therefore ideal for sustainability—PHA, PLA, and starch blends.
Controversy
Bioplastics are not a perfect solution to plastic pollution. Even when they are designed to be compostable—as well as marketed as biodegradable—most are sent to landfills or incinerators due to a lack of local composting facilities or waste sorting. Because most modern landfills are closed off from open air, these bioplastics break down anaerobically and release methane, a greenhouse gas 25 times more potent in heat retention than carbon dioxide.
Only a small percentage of bioplastics labeled compostable can properly mineralize in residential composting bins. The majority are compostable only in industrial standards, which require factors such as particle size, moisture content, oxygen flow, and temperature to be controlled at all times for the compost to be an effective fertilizer.
With so many conditions that must be maintained, the following environments are ranked from most suitable for bioplastic biodegradation to least suitable:
- Compost: consists of temperatures up to 150 °F and high concentrations of bacteria and fungi.
- Soil: consists only of high concentrations of bacteria and fungi.
- Freshwater: provides high concentrations of bacteria.
- Marine water: provides starkly low concentrations of bacteria.
As suggested from the list above, marine water offers the worst conditions for bioplastic biodegradation. Once bioplastics enter the ocean, they are expected to act the same as petro-based plastics in marine water, taking several decades to completely break down.
Improvement
There are no widespread recycling methods for bioplastics. The usefulness of bioplastic packaging at the end of its lifespan extends only as a fertilizer for the production of crops. Consider then if it is a problem at all that bioplastics cannot be recycled. They function just as we intended them for—to disappear.
It’s hard to create a material that’s strong enough to satisfy the consumer’s needs, and then disappear once the consumer’s needs are met.
Once we’ve reached reality of that ideal world of bioplastics, the very second you crack apart the casing around that new headphones set, or peel away the screen covering on the latest version of the Apple iPhone, or blast open the top seal of a Doritos bag, the packaging will all cease to be.