CAREER: Illuminating molecular-level effects in new plant-based nanocomposites for additive manufacturing by stereolithography

NON-TECHNICAL SUMMARY Plants are remarkable organisms. They are towering, sunlight-driven factories that use carbon dioxide, water, and soil nutrients to create all the materials they need to survive, including the factory itself! While many human-made factories are constructed using concrete, plants use long molecules called polymers to create supporting structures. These structures allow a plant to stand up and reach out for sunlight, move water and nutrients between its organs, and protect itself and its offspring. One of these polymers is called lignin, and it functions like the cement in concrete; it is a sort of glue that holds everything together. It also has a chemical structure that is very similar to many of the plastics that people use in everyday life. Therefore, lignin could be used to make new plastics, including those used for 3D printing. Using lignin to 3D print objects would be like how plants use lignin to manufacture their leaves, stems, roots, and seeds. Also, since plants are a renewable resource, plastics made from them would also be renewable. The goal of this project is to learn how to control the structure of lignin taken from plants and use it to create new materials for 3D printing. New chemistry methods to extract, modify, and use lignin will be explored. The principal investigator will also study how using lignin and other plant polymers could help people in rural communities get good jobs related to these new materials. In addition, the research plan will be augmented by enriching undergraduate education, supporting undergraduate research opportunities, and disseminating cutting edge research principles to K12 students through Research Experiences for Teachers program. TECHNICAL SUMMARY The overarching goals of this CAREER plan are to (1) develop 3D printable composite resins consisting of suitably modified nanocellulose and lignin, (2) use this research as a platform to introduce students to fundamental principles of polymer science that underpin renewable bioproducts, and (3) contribute to global efforts to reduce the concentration of atmospheric carbon. The proposed CAREER plan will advance knowledge and understanding in several fields, including synthetic chemistry, polymer science and engineering. The aims include (1) establishing approaches to control the oxidation state of aliphatic carbons in lignin during fractionation and upgrading, (2) developing techniques to control lignin structure and function as a photopolymerizable polymer matrix, and (3) identifying methods to blend modified lignin feedstocks to create new stereolithography resins. These activities explore transformative concepts, including producing entirely renewable biocomposite resins for 3D printing. In addition, the research plan will be augmented by (1) enriching undergraduate education, (2) supporting undergraduate research opportunities, and (3) disseminating cutting edge research principles to K12 students through Research Experiences for Teachers. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.