by Carolyn Frank
Grade 10 - Homeschooled (Farmington, ME, United States)
First Place
Plastic is a wonderful resource, allowing modern society to create the previously impossible. It is used in medicine, technology, structural engineering, and, most prominently, in our homes. It saves human lives and builds new things every day. However, this miraculous substance also brings harm and death to hundreds of species of wildlife, thanks to human carelessness. One of the most common problems caused by plastic pollution is the consumption of plastic film by endangered sea turtles such as the Leatherback turtle. When plastic shopping bags are used and then disposed, they are littered into the environment, where they will eventually reach the ocean. These plastic bags can float unchanged in the sea for hundreds of years, where they mimic jellyfish, the main food source of Leatherback turtles. These plastic bags are consumed by sea turtles and cause them to starve and die. My company, Eco-Plastics, has formulated a solution to stop the harm to sea turtles caused by plastic pollution. By creating a water-soluble plastic film that will only dissolve in saltwater, plastic bags created from this material would dissolve quickly on contact with seawater. If this plastic dissolved only in saltwater, it could be made into plastic bags and be used in the presence of freshwater. I am asking for a grant from The Sustainability Funders in order to put my theory into action and experiment with different polymer structures that will create this saltwater-soluble plastic.
Leatherback turtles are the largest species of turtle on Earth, weighing up to 2,000 pounds as adults. They are listed by the International Union for the Conservation of Nature (IUCN) as Vulnerable, a subcategory of all endangered species. These slow-moving giants range in the warm waters near the equator, where their diet consists of mainly jellyfish, along with several other tunicates and cephalopods. Leatherback sea turtles are not fished for human consumption, but they are harmfully affected by humans in several other ways. Many countries harvest and eat Leatherback turtle eggs, which can drastically reduce the overall population. Additionally, because of their size, Leatherback turtles usually cannot escape from nets, even nets equipped with Turtle Excluder Devices, and many individuals are accidentally trapped and killed. Leatherbacks are also caught on hooks and die when feeding on the bait from longlines. But the main threat to Leatherbacks comes from plastic. Plastic bags and pieces of plastic sheeting float in ocean currents, mimicking the turtles’ main food source: jellyfish. Mistaking this plastic as food, turtles ingest it in large amounts. Once in their stomach, this plastic cannot be digested and will create an obstruction in their digestive tract, ultimately starving them to death. The plastic also slowly leaches harmful chemicals into the turtle’s bloodstream. Hundreds of Leatherback turtles are killed every year by the ingestion of plastic. However, if this plastic dissolved on contact with saltwater, hundreds of sea turtle lives could be saved.
Though there are several existing types of dissolvable plastics on the market today, the most common is PVA, or polyvinyl alcohol. This water-soluble polymer is created by “dissolving polyvinyl acetate (PVAc) in an alcohol and then treating it with an alkaline catalyst such as sodium hydroxide” (Britannica: Polyvinyl alcohol). This causes the polymer to be hydrolyzed, removing the acetate groups and replacing them with alcohol groups (iDissolve). The alcohol groups contain a small electrical charge, called a dipole, that is attracted to water molecules, which also contain a dipole. This causes the chemical structure of the polymer to dissolve when placed in water. Once completely dissolved, the only byproducts of this polymer are carbon, hydrogen, and oxygen, the base elements. The solubility of polyvinyl alcohol can be changed by replacing different amounts of the acetate molecules with alcohol molecules. For instance, if all or nearly all of the acetate molecules are replaced, it will dissolve in only hot water, but if some acetate molecules remain, it will dissolve in both hot and cold water (iDissolve).
In order to make a polymer that will dissolve only in saltwater, another component must be added to the chemical structure of PVA that will dissolve the polymer only in the presence of salt. The chemical composition of saltwater consists of water, sodium and chloride. When table salt (sodium chloride or NaCl) is dissolved in water, the sodium (Na+) and chloride (Cl–) atoms separate and bond with water molecules. Since each water molecule has one oxygen (O–) atom and two hydrogen (H+) atoms, the positive sodium atoms attract the negative oxygen atoms, while the negative chloride atom attracts the two positive hydrogen atoms. In theory, if a polymer was engineered to contain an element with a strong electronegativity and a positive charge that would keep it from dissolving in fresh water, the extra element would then disintegrate the polymer when it is placed in saltwater, due to the presence of chloride, which also has a strong electronegativity and a negative charge. This element would also need to be non-toxic so as not to cause chemical pollution once dissolved.
Creating a plastic that is both saltwater soluble and non-toxic to the environment will take time, expertise and research. With the help of an experienced chemist and plastic engineer, the first step would be to experiment with the basic structure of existing soluble plastics, trying new molecular additions to find what will work best in the overall chemical structure. Eco-Plastics currently has an assembled team of chemists, chemical engineers and polymer engineers. In the past, we have used this team to create new polymers that are biodegradable and non-toxic. Our company mission is to create plastics that can be used in modern technology but will still help protect our environment. Our engineering team will work carefully to create the polymer described above while making sure it conforms to our company standards. This project will also require time and resources to reach completion. We have set a deadline of two years for our project. When this plastic, named SaltSol, is created, it will also take time to implement it in a variety of situations where it can replace plastic products such as shopping bags. A total cost estimation is $160,000. This includes $13,000 for raw materials and $147,000 for lab space, equipment, and extra hired workers.
I have chosen The Sustainability Funders to ask for support because of your commitment to the transformation of the modern materials economy in order to promote environmental sustainability and awareness in modern production and consumption (Sotos). A saltwater-soluble plastic would not only promote environmental conservation by saving hundreds of endangered marine turtles, but it would also benefit thousands of other marine species. SaltSol plastic could be adapted to a wide range of uses in order to reduce the amount of non-soluble and non-biodegradable plastics that are currently filling our landfills. After use, this plastic could be safely dissolved in saltwater and then dumped down the drain, reducing trash output worldwide. This salt-water soluble plastic would also be free of harmful chemicals such as bisphenol-A and phthalates, making it healthier for humans and safe for food storage and preparation. SaltSol plastic, when created, could potentially decrease plastic pollution and raise consumer awareness about environmental problems.
In conclusion, engineering a plastic that will dissolve only in saltwater can help reduce trash, save lives of endangered species, and promote sustainability. If our SaltSol plastic is made from nontoxic bioresins, it will be completely biodegradable and compostable. This plastic will also dissolve instantly on contact with saltwater, unlike existing compostable plastics, which take weeks to fully decompose in water. This means that there will be no new plastic bags floating in the ocean, and endangered turtles such as the Leatherback sea turtle can be saved from future harm. By funding our new plastic, The Sustainability Funders can do an active part in saving endangered species, the ocean, and the entire planet.
References
Anderson, Genny. (8 Oct 2009.) Marine Science: Seawater Composition. Retrieved from http://www.marinebio.net/marinescience/02ocean/swcomposition.htm
Clark, Jim. (Mar 2013.) Electronegativity. Retrieved from http://www.chemguide.co.uk/atoms/bonding/electroneg.html/
Counterman, Craig. Electronegativity Table of Elements. Retrieved from http://www.tutor-homework.com/Chemistry_Help/electronegativity_table/electronegativity.html/
Encyclopedia Britannica. (23 July 2009.) Britannica: Polyvinyl acetate (PVAc). Retrieved from https://www.britannica.com/science/polyvinyl-acetate/
Encyclopedia Britannica. (23 July 2009.) Britannica: Polyvinyl alcohol (PVA). Retrieved from https://www.britannica.com/science/polyvinyl-alcohol/
iDissolve. (14 Mar 2013.) iDISSOLVE: Water Soluble Plastics. Retrieved from http://www.idissolve.com/features/water-soluble-plastics/
NOAA Fisheries. (10 Feb 2016.) Sea Turtles: Leatherback Turtle (Dermochelys coriacea). Retrieved from http://www.nmfs.noaa.gov/pr/species/turtles/leatherback.html/
Raj, Guarav. (5 Sep 2013.) What Happens if NaCl (table salt) is Mixed With Water? Retrieved from https://www.quora.com/What-happens-if-NaCl-table-salt-is-mixed-with-water/
Sotos, Eleni. (1 Feb 2016.) The Sustainability Funders: Who We Are. Retrieved from https://sites.google.com/site/sustainabilityfunders/
World Wildlife Fund. (April 2016.) Sea Turtles: Leatherback Turtle. Retrieved from http://www.worldwildlife.org/species/leatherback-turtle/