The proposed project aims to develop a chemical process to convert a material found in plants called lignin to a more valuable material called lignin-formaldehyde (LF) resin. Completely bio-based LF resins can replace of phenol-formaldehyde resins, which a common material used in myriad of industrial products, such as countertops, coatings, adhesives, billiard balls, etc. Lignin contains phenolic units that make it a potential renewable substitute for phenol in the synthesis of the resin. However, lignin itself has limited reactivity towards formaldehyde. To overcome this problem, a new catalytic process is proposed to enhance the reactivity of lignin products. The proposed research may lead to the development of technologies that add value to lignin from biomass waste streams and can have positive impact on the environment and on rural economies.
Catalytic depolymerization and demethoxylation of lignin into small fragments can generate free phenolic hydroxyls and free ortho positions for formaldehyde addition and crosslinking. This pathway can overcome the limited reactivity of lignin towards formaldehyde. Preliminary results have shown that inexpensive catalysts, such as metal sulfides, could catalyze depolymerization and demethoxylation of lignin. LF resins can be subsequently synthesized from phenolic compounds with two ortho positions and be cured with the addition of multiple-ortho-position compounds. Catalysts will be screened through model compound studies on dimers featuring various kinds of interunit linkages. The optimal ratios of monomer/dimers (and/or oligomers) for LF resin synthesis will by studied by synthesizing LF resins from model compounds. The research results will be incorporated in courses at Virginia Polytechnic Institute and State University aimed at educating students about biomass-derived fuels and value-added products. Outreach activities to high school students are planned with emphasis on attracting members of underrepresented groups into pursuing careers in science and engineering.
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.
