Though not everyone agrees that the world has a plastic problem, let us assume it’s real. Let’s also assume that it could have serious environmental consequences if it is not dealt with. Solving the problem would partially depend on finding a material capable of replacing plastic for most applications. Bioplastic is not that material.
Bioplastics, which are plastics made from organic materials, are often misunderstood by people who do not know the chemistry behind plastic manufacturing. Such misunderstandings lead to the belief that all bioplastics are compostable. People are led to believe that you can put bioplastics in a landfill and they will break down just as easily as paper. This is not the case.
Plastic Is Still Plastic
Plastics are made from polymer chains. Those polymer chains can be derived from any number of natural substances, including petroleum. Yes, petroleum is a natural substance. It is taken out of the Earth. Nature produces it through the decomposition of living matter.
Nearly all the world’s plastics are derived from petroleum. Whether oil or natural gas acts as the starting point, plastics are produced by distilling petroleum and then capturing some of the distilled monomers to create the polymer chains that become plastic.
Polymer chains are that which give plastic its advantageous strength-to-weight ratio. It doesn’t matter whether you start with petroleum or sugar cane, bonding polymer chains together creates a very strong substance that can be combined with additives to make a variety plastics. In the end, plastic is still plastic.
They Exhibit the Same Properties
Plastics exhibit the same properties regardless of the polymers from which they are made. Some types of plastics accentuate some properties over others, but the basic building blocks are the same. Oil-derived plastic is impervious to water, for example. So is bioplastic.
In order to use a bioplastic to manufacture a coffee cup, it has to be waterproof. It also can’t be so weak that water breaks the material’s chemical bonds and causes it to fall apart. By the way, that’s why paper cups have a plastic lining on the inside. They would not hold water otherwise.
The point here is that bioplastic does not necessarily decompose as quickly as people think. Only a small number of bioplastics decompose fast enough to be composted. Even so, conditions have to be just right. Most compostable bioplastics have to be composted in an industrial setting where conditions are tightly controlled. They do not easily compost in the backyard along with your grass clippings.
Recycling Is More Difficult
Another big consideration with bioplastics is recycling. According to Seraphim Plastics, an industrial scrap plastic recycler based in Tennessee, bioplastics can make recycling more difficult than it already is. Bioplastic has to be separated from petroleum-based plastics because you cannot mix the two when manufacturing end products.
In terms of curbside recycling, the last thing we need is another form of plastic to sort out. Sorting is already labor-intensive and cost prohibitive. Throwing bioplastics into the mix would make curbside programs even less profitable than they already are.
Industrial bioplastics can be recycled in much the same way their oil-derived counterparts are. But for recycling to be profitable, there has to be a market for bioplastic regrind. The market may be there someday, but it is not there right now.
It’s easy to assume that bioplastics are the solution to the plastic problem simply because of their name. Yet making a plastic from sugar cane rather than petroleum doesn’t do much except reduce the amount of petroleum a plastic manufacturer utilizes. It doesn’t really help solve plastic problem.