Date of Award

January 2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Surojit Gupta

Abstract

Lignin, as an abundant source of bio-renewable material, has been a subject of investigation for many years. Due to its chemically heterogenous and recalcitrant nature, 98% of the material is discarded as waste [3]. Laboratory groups have been exploring lignin’s potential as a value-added ingredient to promote biocompatibility, biodegradation, and substitute toxic, petroleum-based materials [4,6]. In our laboratory, lignin has been utilized as precursor for carbon foam, yielding highly porous structures after pyrolysis [5], and has also been shown to be compatible with other bio-waste materials [8]. The next stage of research focusses on controlled additions of Cu or Distiller’s Dried Grains with Solubles (DDGS) to reinforce lignin during pyrolysis. To achieve the goal of enhancing and controlling the properties of pyrolyzed lignin, Cu was used as a base metal for designing scaffolds. As an associated bio-waste material, DDGS has been shown to have significant commercial potential beyond edible materials [14-20]. Separate additions of these materials are combined with lignin using similar design principles for manufacturing, methodology of fabrication, and characterization. In both composite systems, lignin is observed to be a low temperature sintering aid, or pore former, while acting as a strong mechanical binder. Cu or DDGS additions within a lignin matrix resulted in strength enhancement as compared to fabricated lignin foams while achieving highly porous composite foams. Such foams exhibit temperature-controlled wettability, resulting in hydrophobic behavior when fabricated at 300 °C, or hydrophilic behavior when fabricated at 900 °C. The research concludes that Cu and DDGS can be effective reinforcements into lignin-based carbon foams. In addition, lignin can be a low-temperature sintering aid which is derived from bio-renewable sources.

Download

Share

COinS