The Department of Chemical and Biomolecular Engineering welcomes Dr. Mojgan Nejad, Assistant Professor from the Michigan State University Department of Forestry, as a part of the ChBE Spring Seminar series. Her seminar, titled “Lignin, The Brown Gold of Bioeconomy Era,” will take place on Thursday, March 1st, 2018 from 2:00-3:00pm in Earle 100.
Lignin is the most abundant aromatic natural polymer, making up almost one third of the dry mass of wood and other plants. Lignin is a natural polyphenolic compound and contains both aliphatic and aromatic hydroxyl functional groups, which makes it a great candidate to replace petrochemicals in polymeric resin applications. However, depending on the source (hardwood, softwood or annual crops) or extraction process (kraft, organosolv, sulfite, soda and enzymatic hydrolysis) there are significant variations in lignin structure and properties. The first step is to evaluate suitability of each lignin for intended application. For instance, we can measure the hydroxyl functional groups of lignin by phosphorus nuclear magnetic resonance spectroscopy ( 13 PNMR) or other advanced analytical techniques to predict whether that lignin would have high reactivity toward formaldehyde or isocyanate. In one of our recent studies, we used more than 10 different lignin samples to formulate lignin-based phenolic adhesives by replacing 100% of phenol with lignin. Among tested lignins, a corn stover lignin isolated through enzymatic hydrolysis proved to be the most suitable lignin for this application. The formulated lignin-based adhesive had similar wet and dry strength as of a commercial phenol-resorcinol formaldehyde adhesive. Based on our characterization results, lignins that had high hydroxy-phenyl content or very high guaiacyl content had higher reactivity toward formaldehyde and were more suitable for phenolic adhesive application. Additionally on weight basis, replacing 100% of phenol with lignin resulted in reducing the formaldehyde consumption by 75%.
Mojgan Nejad is currently working as an Assistant Professor in Michigan State University. Dr. Nejad has a bachelor degree in Applied Chemistry and PhD in Wood Science. Her PhD dissertation, conducted at the University of Toronto, focused on “Modeling correlation between coating properties and their weathering performance on modified wood”. Dr. Nejad also holds a Professor (status only) position at the Mechanical and Industrial Engineering Department in University of Toronto, which enables her to co-supervise graduate students and projects there. Her current research projects are mainly focused on developing lignin-based bioproducts (adhesives, coatings and foams) and most of them are conducted in close collaborations with industrial partners.