In an age where sustainability and eco-friendliness is more than just a fad, and has become a real necessity, the search for better plastics always have been a thorny issue. Plastics are known as tough, durable and versatile materials for wide range of applications. Ironically, these same characteristics make them so hard to dispose when we don’t need them any longer. Disposed plastics don’t mix well with other materials, which make them a common cause of pollution. In addition, the fact that traditional plastics are synthetically made from non-renewable petroleum also doesn’t help their case. Thus, an emerging demand for sustainable and eco-friendly plastics is underway.
Generally speaking, eco-friendly plastics can be categorized into bioplastics, biodegradable plastics and recycled plastics. Out of these three, the bioplastics sector is already perceived to be the promising, yet gradual step towards sustainability.
This material comes from renewable, natural sources like vegetable oil, corn starch, pea starch and orange rinds. The premise with bioplastics is if plastics are made from natural materials to begin with, they would break down more easily and quickly when disposed. Unlike traditional plastics, bioplastics do not produce net increases in carbon dioxide emission when they break down, because the plants used to make their raw materials used to absorb the same amount of carbon dioxide to begin with. Furthermore, most bioplastics are compostable into natural materials that blend harmlessly with soil. Bioplastics are often confused with biodegradable plastics. Some bioplastics can be degraded like these biodegradable plastics, but not all are. It is therefore more appropriate to call bioplastics “bio-derived plastics” to further distinguish them from biodegradable and other plastics type.
Biodegradable plastics have small, biodegradable materials (like starch) inserted in their backbone structures to initiate biodegradation in suitable conditions. True biodegradable plastics can undergo fast decompositions in both naturally aerobic (composting) and anaerobic (landfill) conditions. On the other hand, some biodegradable plastics have additives incorporated in their chemical structures too so they can be either degraded by UV radiation (photodegradation) or by oxidation process (oxo-degradation), then later on by bacteria or other microbes. Technically, all plastics can be biodegraded by bacteria, but it takes tightly-controlled conditions to make degradation happen fast and effectively. Plus, plastics have widely differing rates of degradation, with most plastics having very slow rates to be considered degradable at all. By nature, biodegradable plastics are petroleum-based (like traditional plastics) that doesn’t always break down easily into harmless substances.
Another alternative solution to the problem of plastic disposal is to recycle old plastic materials into new ones. However, plastic recycling lags far behind other items such as newspapers and corrugated fiberboards. In the U.S., only 7% of the total plastic waste generated in 2009 was recovered for recycling. This is perhaps due to underlying challenges with segregation (mix-up with other materials including organic wastes), the amount of toxic by-products produced during reprocessing and the end quality of the recycled materials (as recycled plastic resins have different properties from virgin reins). Still, recycling is another big possibility in curbing down pollution from plastic wastes and reducing exhaustive impacts we pose on petroleum resources.
So, are bioplastics and biodegradable plastics really good?
Production and use of bioplastics and biodegradable are regarded to be generally better as they are more sustainable and eco-friendly than traditional plastics. However, it is not always that simple. It is important to see things in their entirety to understand whether “sustainability” and “eco-friendliness” of these plastics do more good than harm. Bioplastics production will still involve petroleum as a main energy supply, while biodegradable plastics still have petroleum as raw material source. Moreover, bioplastics production would also require large areas for raw materials, which will shift agricultural lands from food to bioplastics production. Most bioplastics and biodegradable plastics still don’t decompose readily; some need strict conditions (like high temperature and required oxygen levels) and may still take years to break down. Further, even though bioplastics reduce greenhouse gas emissions through carbon dioxide reduction, when decomposition is made in landfills, they also generate methane, another greenhouse gas. Lastly, prices of bioplastics and biodegradable plastics are still not cost-competitive with traditional plastics, making them a hard-sell among end users.
Thus, the search for better plastics is still far from over. Until then, let’s be smarter about how we use plastics and how to get rid of them when we’re done with them!