A [Bio] Plastic Perspective by Samantha Schulman, January 22 2020, 0 Comments
Every once in a while, when I just can't hold back, I explain to the cashier at the grocery store the reasons why I will never again allow my items to be packed in a toxic plastic bag. While I know it's fruitless (and admittedly a little preachy) to scold cashiers who are just doing their jobs, I cannot help but picture the flock of plastic bags caught in the tree branches lining my New York City side street. I also shop primarily at second-hand stores to avoid buying new fashion, even if it means that sometimes—at least in the eyes of my mother—my clothes are a little crazy. While reusable tote bags and vintage clothing are great ways to reduce the pollution caused by the production of synthetic materials, I knew that I wanted to find a more extensive way to help slow down climate change and pollution.
Therefore, I have expanded my daily practices into a career—studying and exploring broader solutions to combat the negative environmental impacts of mass manufacturing. In the course of these studies, I've become particularly focused on the application of waste as a resource and closed-loop production, zeroing in on sustainable material alternatives and even constructing my own homemade biodegradable plastic.
Current State of Plastic
Within the span of the last century, society discovered the resources and technology to develop a lightweight material that is so durable, it will never break down. As more commonly known, plastic, is made up of long chains of polymers that are synthesized from the hydrocarbons in fossil fuels, i.e. petroleum, natural gas and coal. These are then bonded into malleable structures that have a low melting point and harden when cooled. Resistant to water, oxygen and bacteria, the materials are perfect for carrying goods, packaging food, transporting medicine and mimicking everyday objects such as utensils and small toys. Plastic is cheap to produce in mass quantity and lightweight, making it easy to distribute across the world and no wonder that plastic is ubiquitous. Even in my own life, try as I might to avoid plastic, I am still tempted by the apple chips at my farmers market stored in a plastic bag, and I cannot avoid the prescription medicine at my drug store that is pre-packaged in a plastic container.
Plastic, however, is not all created equal. It encompasses many forms varying in hardness, permeability and toxicity. Plastic is categorized into many factions based on the chemical structure, but first breaks down into two overarching groups.
- Thermoset plastics describe those that undergo a chemical change when heated and retain their structure when cooled. They cannot be re-melted or reformed. This category of plastics can be beneficial to modern society, from the silicone often found in medical devices—as my brother-in-law (a surgeon) likes to remind me—to epoxy resins used to build wind turbines. Even though they cannot be recycled in the traditional sense, because of their durability, thermoset plastics can be used and reused forever.
- Thermoplastics, on the other hand, can be melted down to return to their original state and reconstructed into brand new objects. Intuitively, thermoplastics seem remarkable because they are made to be broken down and recycled; however, it is this same property that dubs them problematic. Thermoplastics are so flimsy that they often only survive one use, and it is not cost-effective to recycle the exorbitant amount of small plastic tools consumed every day. So products like polystyrene take-out utensils end up diverted to landfills.
Regardless of their fate, from the moment thermoplastics are fully assembled, they begin to photodegrade. This means that micro-sized pieces of the material twist and break apart, but the defining chemical polymer structures cling together and never disintegrate. The immutable property of all thermoplastics to photodegrade means the tiny particles navigate into every water source and living being on the planet. This unintended consequence impacts all derivatives of plastic, even the recycled products that are seen as better for the environment. For example, I now know that my Mario Kart polyester sweatshirt made from recycled PET (polyethylene terephthalate) water bottles sheds millions of synthetic microfibers into the water with each laundry cycle. The water drains into the pipes and out to open water, in which even the purified bottles and filtered taps cannot escape the microplastic contamination. The truth is that thermoplastic as we know it is made to last forever and is to be used exactly once.
The “New” Invention
Although derived from fossil fuels, the material characteristics of plastic mimic the wax coatings found in nature, from plant leaves and fruit peels to fish scales and shrimp shells. Inspired by these biological phenomena, researchers have created the same type of polymer structures of thermoplastics, derived instead from plants and microorganisms. Known as bioplastic, ancient societies began making variations of the material around 1500 BCE when the MesoAmericans invented a natural latex to waterproof their clothing. In more recent years, chemists developed a biodegradable plastic made from casein (a protein in milk), and in 1997 two major corporations joined forces to produce what has become the most commercialized variation of bioplastic today—PLA (polylactic acid).
As detailed in The Truth About Bioplastics, PLA is assembled by extracting the sugar and starch from agricultural crops, then breaking down the molecules using water and various weak acids. Once the water evaporates, the glucose form long polymer chains with strong molecular bonds that result in the bioplastic. Born out of plants, PLA will decompose when retired to a high temperature, aerated and nutrient-rich environment, and will release CO2 that is absorbed by plants for photosynthesis.
Unfortunately, PLA itself is a problematic solution, often in an effort to combat its higher price point when compared to synthetic plastics. The increasing demand for PLA results in its mass-production and growing it on farmland that would otherwise harvest food or inhabit wildlife. In an effort to compete with cheap petrochemicals, bioplastic industries may source GMO corn or sugarcane crops, a majority of which are resistant to toxic herbicides and therefore contribute to their increased use over time. Furthermore, the way PLA is disposed of is also far from ideal. The journal article, Biodegradation of Biodegradable and Compostable Plastics under Industrial Compost, Marine and Anaerobic Digestion, specifies that to avoid contaminating community compost piles, the special bioplastic requires an industrial compost site that can reach at least 140°F. However, even though the production of PLA has increased, the number of high temperature industrial compost sites has not—nor has the awareness of how or why to compost.
For example, the farmer’s market where I drop off my food scraps once a week cannot currently accept my PLA food container in their compost collection. Therefore, the 100% biodegradable plastic winds up polluting landfills and oceans all the same, where it will not break down. While this bioplastic is by definition compostable, natural and biodegradable, advertising as such is misleading and it is questionable how advantageous it is for a healthy environment.
Researchers are hopeful that an alternative bioplastic process called PHA (poly-hydroxy-alkanoate) may be headed in a better direction. The PHA process was discovered in the 1950s, but just like PLA, it lost out on a commercial scale due to the prevalence of cheap crude oil. But it is now making a comeback like never before. PHA is engineered in a laboratory by feeding bacteria a plant diet rich in carbon. The single-celled organisms are deprived of vital growth nutrients like phosphorus, oxygen and nitrogen, which forces their cells to store reserves of carbon for energy. The carbon is then extracted and compiled into the polymer chain structure that mirrors that of traditional plastic. While hazardous chemicals may be used to enhance the process, the extraction of PHA can also be carried out without such chemicals, which results in a material that is biodegradable in marine sediment and safe for sea animals to digest.
Waste as a Resource
At first glance, these properties sound exciting for a marine environment at risk. Truth be told, many PHA products are advantageous over their synthetic counterparts. Depending on the manufacturing process, disposable PHA plastics are often safer than petro-based ones because they are derived from renewable resources and are non-toxic to the environment. To take it a step further and reduce pollution from the continued production of disposable bioplastic, the raw materials for PHA can be sourced entirely from organic waste. Hundreds of millions of agricultural byproducts from crops like bananas, pineapples, flax, hemp, lumber and sugarcane are discarded every year and are now being utilized by entrepreneurs to create PHA for uses from food packaging to fabrics. Plant oils from soybean, palm, corn and coconut crops can also be used as renewable carbon sources to feed the PHA bacteria, all of which are available as waste products from their respective industries.
In an ideal world, the production of plastic would be an entirely circular process, where no waste is generated during the life cycle of the product. First, organic waste would be sourced from existing crops (without increasing production of the virgin material) and transformed into a biodegradable object. Once the object has reached the end of its life, it would be composted and transformed into nutrient-rich soil, which would regenerate the farmland to produce more healthy crops.
Through the course of my research, I have become familiar with a number of small companies that have begun making progress on this work. For example, Piñatex collects fibers from inedible pineapple leaves and constructs durable non-woven textiles that resemble the polyvinyl chloride in my pleather skirt. To reduce the carbon footprint of new production of bioplastic, Toronto's Genesis lab and California’s Full Cycle Bioplastics are among the laboratories that source carbon from food waste. Furthermore, Mango Materials discovered that microbes can make PHA from a diet of methane gas waste in place of carbon. In demonstration of Cradle-to-Cradle and carbon-neutral design, their invention decomposes back into methane, but does not increase the greenhouse gas concentration in the atmosphere.
Designing the Future
Artists are also experimenting with bioplastics to encourage analysis of their role in mass distribution. In my next article, I will discuss the current progress of artists who are developing homemade bioplastic, in addition to detailing my own experiments with the material.
Creating bioplastics is just one part of the larger puzzle in moving the world towards the reversal of climate change and pollution, action that will not truly be possible without systematic shifts by companies and governments on a global scale. Carbon emissions will not decrease until all production facilities operate with renewable energy, which could be decades away. While the end of pollution as we know it may be a pipe dream for now, plenty of individual contributions are nonetheless worthwhile. Every personal decision made, from carrying a reusable spork to choosing a bamboo toothbrush, helps collectively and over time to transform human behavior and the cultural zeitgeist. Further examples of these individual changes in behavior include finding out how to compost in your community, using reusable bags and beverage containers, shopping second-hand whenever possible, supporting your small local merchants and repurposing, mending, and taking care of your belongings so less ends up in the trash. Patching a hole in your favorite pair of jeans could be a great place to start!