Department Web-Page

Dr. Justin G Kennemur
Faculty

Dr. Justin G Kennemur

Assistant Professor

Ph.D. Chemistry - North Carolina State University (2010)

Contact Information
Email:
kennemur@chem.fsu.edu
Office:
2005 CSL 850.644.3875
Lab:
2301 CSL
Programs of Research
 Materials
 Organic
 Physical
Research Website
Research Specialities
Chemistry of Materials, Environment and Energy, Nanoscience, Synthesis and Catalysis

Research Interest

Research in the Kennemur Group focuses on the design and synthesis of polymeric materials with the goal of addressing societal needs. An area of great interest is the ability of macromolecules to autonomously self-assemble into a hierarchy of secondary, tertiary, and even quaternary structures. By tailoring and controlling the design at the molecular level, we can investigate the important principles involved in these processes and ultimately tune properties to gain a desired function. Our research is highly interdisciplinary and relies on organic synthesis, polymer synthesis, organometallic catalysis, analytical chemistry to characterize macromolecular structure, and polymer physics and engineering to probe material function. Specific areas of interest include:

Precision Polyolefins and Elastomers

Polymeric microstructures with specific functionalities placed at a precise periodicity along the chain can offer markedly advanced and well-defined properties. A portion of our research is aimed at designing new precision polymers from the ring opening metathesis polymerization (ROMP) of low-strain cyclopentenes. This low-strain makes polymerization of these monomers synthetically challenging and we are leveraging basic equilibrium thermodynamics to produce these materials with high monomer conversion, predictable molar mass, and low dispersity. This success has opened the door to exploration of a variety of materials with branch points spaced exactly five carbons apart; opening a new materials landscape over the more common two-carbon periodicity of typical polyolefins.


Block Polymer Self-Assembly

Block polymers contain two or more chemically distinct polymer segments that are covalently attached at one end. If the two segments are incompatible, (i.e. one is hydrophobic and the other hydrophilic) the segments want to completely phase separate but cannot due to their covalent attachment. A compromise between the thermodynamic desire to fully separate and the entropic penalty to do so, results in microphase separation or the formation of periodic nanostructures densely populated in either segment. The size and morphology of these structures can be controlled by the size of each polymer segment. Our research is exploring new avenues of this self-assembly process by combining block segments with dynamic properties to pioneer new applications in nanotechnology.


Sustainable Polymers

Inherent to the synonymous boom of the petroleum and plastics industry over the last century, many of the polymeric materials produced today are derived from oil and are revered for their high chemical resistance and thermal stability. This poses two growing problems: 1. Petroleum sources are finite and of limited geographical availability and 2. Although polymer longevity will always be necessary for some applications, there are many instances when a plastic serves a single function within a relatively short time frame and is then discarded. Drink bottles, plates, diapers, pens, and packaging materials are just a few examples of typical "single-use" items often made from plastics that will persist in the environment for many years after their use has ended. A revitalized search has begun for new materials that compete with modern petroleum based plastics but are derived from renewable feedstocks (i.e. plants). Knowledge of chemical stability and synthetic design can be used to produce plastics for endurance or improved degradation depending on the application. Our group is pursuing new avenues within this important area of research.

Chirality in Polymers and Block Polymers

Chirality is ubiquitous in both synthetic and biological polymers. Nature utilizes a ballet of stereospecific amino acids with hydrogen bonding capabilities to create secondary helical structures and tertiary helical bundles that offer complex functionality from molecular recognition and catalysis to structural support. Our research aims to judiciously incorporate chirality into synthetic polymers and block polymers to create materials inspired from their biological counterparts.

Publications

Kieber III, R. J.; Silver, S. A.; Kennemur, J. G. “Stereochemical effects on the mechanical and viscoelastic properties of renewable polyurethanes derived from isohexides and hydroxymethylfurfural” Polym. Chem. 2017, 8, 4822-4829.
Neary, W. J.; Kennemur, J. G. “Variable Temperature ROMP: Leveraging Low Ring Strain Thermodynamics to Achieve Well-Defined Polypentenamers” Macromolecules 2017, 50, 4935-4941.
Misichronis, K.; Chen, J.; Imel, A.; Kumar, R.; Thostenson, J.; Hong, K.; Dadmun, M.; Sumpter, B. G.; Hadjichristidis, N.; Mays, J. W.; Kennemur, J. G.; Avgeropoulos, A. Investigation on the Phase Diagram and Interaction Parameter of Poly(styrene-b-1,3-cyclohexadiene) Diblock Copolymers. Macromolecules 2017, 50, 2354-2363.
Neary, W. J.; Kennemur, J. G. “A Precision Ethylene-Styrene Copolymer with High Styrene Content from Ring-Opening Metathesis Polymerization of 4-Phenylcyclopentene" Macromol. Rapid Commun. 2016, 37, 975-979.