Life with plastic? It’s not that fantastic.

You’ve heard about the global plastic pollution problem, everywhere. So, let’s forget about the doomsday approach we’ve come to know and focus on the facts: what we know and how we can address some of this said problem. I’m sure you’ve seen the popular recycling arrow pictograms with numbers in the center all over plastic items you use in your daily life and have likely been told that these numbers mean how it can be recycled. Unfortunately, that is not true. Those numbers actually tell you the resin code–or identity–of the plastic, and having the symbol doesn’t mean the material can be readily recycled. Some of the plastics we interact with just end up in landfills or contaminate the recycling streams and cause other issues along its pathway to the dump.

Take poly(vinyl chloride) or PVC for example. It has the resin code 3, and just so happens to be the third most mass-produced plastic in the world. It’s a plastic that was brought about from our need to redirect the overproduction of chlorine from salt production into some valued-added product. You might encounter PVC more than you’re aware of, from the window framing of your homes, shower curtains in your bathrooms, water plumbing in and out of buildings, coatings for electrical wires, transparent stadium bags, toys, credit cards, and even cookware. It is such a versatile and ubiquitous polymer to multiple industries, as it’s able to provide hardness and hydrophobic properties to the products made from it. Although this polymer has become a heavily involved material in our daily lives it is faulted with an incomplete lifecycle, as most of the aforementioned items are dumped into a landfill or contaminate recycling streams.

When caught sitting in a landfill, PVC starts to decompose and produce toxins, typically from the additives incorporated in the material that provides us with all the versatile items. These toxins and the additives can leech into the environment and cause adverse effects for wildlife and aquatic environments. In addition to the leeched additives, PVC also produces hydrochloric acid as a byproduct of its degradation. This causes complications for the environment, but also for recycling plants. When PVC is recycled, it can go through pyrolysis (oxygen-free incineration) or mechanical recycling (maceration with force), where the contamination from the hydrochloric acid can ruin the potential for the recycled material to be used. In the Fieser Group, we look at different ways to tackle these issues that PVC presents in the recycling process and aim to find chemical routes to give the polymer a closed loop lifecycle. 

My name is Tyeshia, and I am currently a third-year chemistry doctoral student. My research focuses on finding ways to make useful products from waste PVC, mainly from the perspective of having mixed waste stream with that of poly(ethylene) (PE). The project came about from our group’s previous members ability to remove chlorine from PVC, replacing it with hydrogen to make polyethylene-like material¹. This strategy would allow us to better address when PVC impurities end up in polyethylene waste streams. In the process of making some of their materials, we discovered that the method they developed removed chlorine sequentially down the PVC chain, creating block-like segments of polyethylene, while leaving block-like segments of PVC. These types of polymers have never been made before and represent an example where waste plastics can be a feedstock to new materials that are not accessible otherwise. You can think of these block copolymers as segments of PVC and PE connected like those cut out friends you might have made in kindergarten. The only difference is they are chemically bonded to one another and not friends holding hands. We refer to them as PVC-b-PE in our work².

So, what do you do with a material that’s never been made before? Well, block copolymers are commonly used as additives, adhesives, and compatibilizers. They provide the slip in your shampoo, the multitude of textures in makeup products, the adhesion capabilities of glues and bonders used in home renovation projects, or the viscosity of an oil or lubricant in your car. Polymers are used everywhere! 

My work has focused on intentionally making these PVC-b-PE materials and trying to determine how the chemical system works, whether we can control it, and how to produce materials for broader applications like compatibilization. Originally, I started out using pure PVC, which is a static filled white powder, to conduct most of my experiments on. However, in efforts to determine efficacy of the chemistry, I started using commercial items made from PVC and found that we could make these same materials! I used a range of items from vinyl records, piping, saline solution bags found in hospitals, toy frogs and lizards, and even credit cards! So, I guess my life is fantastic when it comes to being able to recycle this plastic.

This is exciting news for us because our team is now taking on the task of finding what limitations PVC items might have if chemically recycled with our methodology. We are also discovering that these materials can have unique and useful properties. So, we are continuing to explore how these materials fair in thermal and physical analysis, with and without additives from commercial items. These properties are what will give us insight into how they can be tuned towards specific applications.

I’m excited about this work because it’s chemistry that takes on a problem that affects the world and allows me to make valuable impact in the pursuit of sustainable future with the work I’m doing directly in the lab. There’s more to do, more chemical routes to discover, and more plastics to tackle, but it’s an exhilarating ride nonetheless. Be on the lookout for updates to our work as we continue exploring our angle, using inorganic chemistry to address plastic circularity. 

Tyeshia Sapp is supported by the Diane Sonosky Montgomery and Jerol Sonosky Graduate Fellowship for Environmental Sustainability Research.

¹ Wood, Z. A.; Castro, E. C.; Nguyen, A. N.; Fieser, M. E. Chem. Sci. 2024, 15, 8766-8774.

² Wood, Z. A.; Sapp, T.; Eberle, B.; Wang, W.; Hunt, S. B.; Barber, S. J.; Cheng-Tan, M. D. C. L.; Zhao, T. Y.; Perras, F. A.; Delferro, M.; Lee, B.; Dadmun, M. D.; Fieser, M. E., J. Am. Chem. Soc. 2025, 147​, 26267-26276.