Ph.D. candidate David Chem and I working with the new FTIR equipment in the PolyNEL lab.

Author: Samantha Glidewell | Major: Chemical Engineering, French | Semester: Fall 2023

This past semester has been my second semester working in the polymers and nano engineering (PolyNEL) lab under my mentor Dr. Keisha Bishop Walters with the department of chemical engineering. This semester I have continued my research regarding lignin modification. Lignin is an abundant naturally occurring polymer that is currently extremely under utilized due to its unique properties such as non-linear structure, a wide range of molecular weight, high hydrophobicity, rigidity and brittleness. My research aims to functionalize the lignin biopolymer and give it new purposes. This semesters project has to do with creating lignin based polyurethane precursors: polyols and diisocyanates. I came up with this project as a result of the research phase of my first semester project where I found that a lot of research has been done regarding lignin modification to increase the number of hydroxy groups present for applications as a polyol in polyurethane synthesis. However, there was a clear lack of research done regarding lignin based diisocyanates. Since diisocyanates are the other primary component of polyurethane chemistry and are the root of a lot of the safety risks associated with polyurethane production, I set out to find a safer alternative by using lignin. Using lignin based feedstocks allows for not only a product that takes less of a toll on the planet in the end of life cycle, but also minimizes human health and safety risks due to toxic byproducts and starting materials that are currently used for polyurethane synthesis. In this project, the lignin polymer is modified to produce a polyol via phenolation and hydroxypropylation reactions that are intended to increase the number of available aromatic and aliphatic hydroxyl groups in lignin, respectively. Additionally, lignin monomers, vanillyl alcohol and guaiacol, are utilized to form a lignin-based diisocyanate following a series of reactions, including Williamson etherification and Smiles rearrangement reactions. Then the lignin-based polyol and diisocyanate precursors are both utilized to produce an entirely lignin-based polyurethane. This method of lignin based polyurethane production eliminates the need for cyanide as a reactant as well as eliminating the production of toxic phosgene gas byproduct. Although this past semester has been my last under the honors college research grant, I plan to continue this lignin based polyurethane project. As I finish out the project, I plan to present my results at the Society of Plastics Engineers ANTEC conference in March. Here I will present a poster about my project alongside other undergraduate researchers from the PolyNEL lab. Working as an undergraduate researcher for the past two semester has opened so many doors for me, from presenting at conferences to setting the foundation for what I hope to achieve as a graduate researcher in the coming years. The PolyNEL lab group has created such an encouraging and safe environment for me a new researcher, and I admire the passion and work ethics of everyone in the group, especially that of my mentor Dr. Walters and Ph.D. candidate David Chem who has mentored me just as much as Dr. Walters has.