About This Project

Plastic waste is extremely durable and can be harmful to organisms and their ecosystems when not managed properly. While current recycling methods can efficiently process certain plastics, some common plastics are not recyclable. Switchable hydrophilicity solvents (SHS) change from biphasic to monophasic when exposed to CO2. I hypothesize that solvents with similar structures to plastics will separate plastic materials into base components more efficiently than current recycling methods.

Ask the Scientists

What is the context of this research?

There is more plastic usedthan ever before. Despite the increase in waste, there are no efficient recycling procedures for plastics like polystyrene, polyvinylchloride, or mixed plastic waste.

Switchable hydrophilicity solvents (SHS) change from biphasic to monophasic when exposed to CO2, which allows for distinct separation between hydrophilic/hydrophobic material in packaging. SHS dimethylcyclohexylamine is currently used to process multilayer flexible packaging. Unfortunately, beyond this, not much work is being conducted on recycling plastics with these solvents.

This project aims to fill the gap in research by processing materials via three SHS. The hypothesis is that SHS will process materials with similar structures most efficiently.

What is the significance of this project?

Improving recycling processes is crucial as the amount of plastic waste is immense and has many repercussions for the planet. This experiment could contribute to streamlining pre-existing recycling procedures as well as finding a more efficient and inclusive recycling process (even if it is only part of the process). Many curbside recycling programs do not accept some of the most commonly used plastics such as polystyrene, polyvinyl chloride, and mixed plastics. If the procedure described in this experiment is functional, it could be used on a larger scale, thereby removing more plastics from the landfill. Additionally, the innovation of this research is in that most work with SHS are on the discovery of them over recycling plastics with them.

What are the goals of the project?

When all project materials are received, food waste multilayer flexible plastics (MFP), commonly seen in potato chip bags, will be separated using a known procedure. We will separate the MFP into its components using 99% dimethylcyclohexylamine switched with a CO2 bubbling system and analyze them with NMR and scanning electron microscopy (SEM) before and after SHS treatment. The analysis will reveal the purity of the final sample and how "good" the separation by SHS was. Then, the steps above will be repeated for four other materials. For materials other than MFP, three solvents will be tested (dimethylcyclohexylamine, dimethylbenzylamine, and2-(dibutylamino)ethanol).