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McKelvey School of Engineering

EECE Seminar - Dr. Mark Thies

Friday, October 7, 2022 | 11:00 AM - 12:00 PM

Uncas A. Whitaker Hall, Whitaker Auditorium, Room 100
6760 Forest Park Pkwy, St. Louis, MO 63105, USA

Mark C. Thies, Dow Chemical Professor
Department of Chemical and Biomolecular Engineering
Clemson University

Creating Liquid–Liquid Equilibrium between Lignin and Aqueous Renewable Solvents: Facilitating Conversion to Carbon Fibers, PU Foams, and Activated Carbons

 

Although lignin is second in abundance only to cellulose, its conversion to higher-value materials, vs. just being burned as fuel, continues to be a significant challenge.  In particular, the impurities inherent in lignin (polysaccharides and metal salts), along with the wide range of functionalities and molecular weights in lignin, can create numerous problems when unpurified and unfractionated lignin is substituted directly into a process or formulation. Furthermore, today it is imperative that lignin-refining strategies also include sustainability as a core principle.
We have discovered that hot renewable organic solvents that form homogeneous solutions with water, including lower molecular weight (MW) alcohols and acetic acid, can be used to simultaneously fractionate and purify lignin, both batchwise and continuously.  The key to this so-called ALPHA (Aqueous Lignin Purification using Hot Agents) process is the formation of two liquid phases in equilibrium, one liquefied lignin and the other solvent, when solid lignin is contacted with a hot, one-phase aqueous solvent. With the lignin partitioning between the two phases, control of both molecular weight and purity becomes possible. 
ALPHA-processed lignins are being investigated for three large and growing markets:  (1) high-performance carbon fibers for automotive applications, (2) rigid polyurethane foams for spray insulation for buildings, and (3) activated carbon for food and pharmaceutical use.  Here, we demonstrate how control of molecular weight, and even the concentration of specific impurities, leads to improvements in the properties of the final commercial products.
In a different thrust, we are also studying very old (i.e., “prehistoric”) lignin.  Here we seek to elucidate the relationship between oligomeric compositions of pyrene, and the propensity of these unique, carbon-rich materials to form liquid crystalline materials. Pure pyrene trimer (MW = 598 Da), isolated via supercritical extraction, forms 100% mesophase at only 290 °C.  The extent to which this desirable, liquid-crystalline state will continue to exist in well-defined mixtures of monomer through tetramer is under investigation.

Event Type

Seminar/Colloquia

Schools

McKelvey School of Engineering

Topic

Science & Technology

Department
Energy, Environmental & Chemical Engineering
Event Contact

jesi@wustl.edu

Speaker Information

Dr. Mark Thies is the Dow Chemical Professor of Chemical and Biomolecular Engineering at Clemson University. He received his Bachelor of Chemical Engineering from Georgia Tech, worked a couple years for P&G developing Jif peanut butter and Duncan Hines cake mixes, and then returned to academia for his Ph.D. at the University of Delaware before joining the ChBE faculty at Clemson.  Mark was a Humboldt Fellow at TUHH in Hamburg, Germany, a Marie Curie Fellow at NTUA in Athens, Greece, and is also an AIChE Fellow.  
His research interests are focused on materials and energy research where thermodynamics, phase behavior, and equilibrium-based separations play key roles.  Today his emphasis is on developing higher-value applications from poorly defined, oligomeric systems, including both “prehistoric” lignin and lignin from today’s plants and trees.
Dr. Thies is the author of 100+ archival publications, including 4 patents and 5 book chapters, and has directed research funding from PRF, NSF, DOE, ARO, ARL, AFRL, AFOSR, and multiple global companies and small businesses, as well as an NSF ERC on Fibers and Films. Finally, Mark is on the Editorial Advisory Board for the journal Carbon, and organized and chaired the World Conference on Carbon in 2010.

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