Date of Award
Master of Science
Chemical and Biological Engineering
Eric W. Cochran
This thesis introduced two of my research projects: the nanocomposite gels study of surface-initiated block copolymer, and lignin based polymer that directly through pyrolysis lignin. The purpose for the nanocomposite gels study is finding the factors that will affect the gel formation. For the pyrolysis lignin polymerization study, the purpose is to use functionalized pyrolytic lignin directly though polymerization process to obtain lignin based polymer.
The nanocomposite gels study is based on the research results from Sri-Harsha Kalluru’s Ph. D work. Kalluru successfully synthesized the exfoliated block copolymer from norbornene and cyclopentene, which could form gel when mixed with tetrahydrofuran and sodium chloride salt. The block copolymer nanocomposite gels used in this work has little difference than the Kalluru’s work, 5-Ethylidene-2-norbornene and cyclopentene are two monomers that for nanocomposite block copolymer synthesis. As conducted gel tests of various nanocomposites, the nanocomposite only in certain molecular weight and 5-Ethylidene-2-norbornene fraction range can form gel. The salt and polymer concentration effects were different for different nanocomposites. Also, the kinetics tests showed the gel formation process as the stirring time increased.
The lignin based polymer study demonstrated the process of modifying pyrolytic lignin to functionalized lignin that could be used to make lignin based polymer. The hydroxyl groups in pyrolysis lignin were first modified by methacrylate groups before the polymerization process, methacrylate groups can provide the double bonds during the polymerization process. Free radical polymerization and Reversible addition-fragmentation chain transfer polymerization were used for poly(lignin methacrylate) synthesis. The more controllable RAFT polymerization was chose for synthesizing lignin methacrylate polymer. To avoid the inhibition during the polymerization process, acetylation process is necessary to convert excess hydroxyl groups to acetate groups in the lignin methacrylate. The Functionality 1 lignin methacrylate were used as monomers for poly(lignin methacrylate) synthesis, the derived polymer were tested though GPC, TGA, and DSC for characterization.
Huang, Yuerui, "Nanocomposite gel study of surface-initiated block copolymer by ring-opening metathesis polymerization and lignin-based polymers directly from pyrolysis lignin via RAFT polymerization" (2018). Graduate Theses and Dissertations. 17212.