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Nicholas Rorrer

Postdoctoral Researcher, Polymer Engineering and Biomaterials Development

Nicholas.Rorrer@nrel.gov | 303-384-6206
Orcid ID http://orcid.org/0000-0001-9134-5853

Research Interests

Nic Rorrer is a postdoctoral researcher in the National Bioenergy Center’s Chemical and Material Process Development group at the National Renewable Energy Laboratory (NREL). His main research interests are the synthesis of performance-advantaged materials from biomass conversion and polymer characterization and modeling. Specific areas of focus include:

  • Biomass-enabled performance-advantaged reinforced plastics

  • Synthesis of polymers from renewable sources

  • Plastics recycling and upcycling

  • Experimental determination of polymer rheology and modeling of polymer processing

Areas of Expertise

Polymer Synthesis from Biomass

Nic specializes in synthesizing polymers from biomass, which includes separating monomers from fermentation media, purifying the separated monomers, and subsequently polymerizing the monomers. Polyesters and polyamides synthesized from biomass are of prime interest due to the inherent functionality available to biomass. Nic also established NREL’s polymer synthesis and characterization laboratory allowing further fundamental science research on bio-derived polymers.

Photos of laboratory equipment including bench-scale reactors, extruders, and characterization equipment.

NREL’s polymer synthesis and characterization laboratory includes multiple bench-scale reactors, extruders, and thermal, rheological, and permeability characterization equipment.

Performance-Differentiated Reinforced Plastics from Biomass

Many monomers from the biological conversion of biomass possess both carboxylic acid or olefinic moieties that make them ideal for use in unsaturated polyesters. The carboxylic acid moieties enable implementation of the olefinic moieties into the backbone of unsaturated polyesters (UPEs) while the olefinic moieties enable cross-linking of the UPEs with reactive diluents. Nic is exploring these monomers, such as muconic acid, to see if they can enable performance-advantaged behavior over their petroleum counterparts. In the case of muconic acid, the two olefinic bonds provide rigidity to the UPEs and two sites for cross-linking, enabling UPEs with higher storage moduli and lower loss moduli. Additional work is dedicated to exploring reactive diluents to find alternatives to styrene.

Schematic showing how lignocellulosic biomass, represented by a photo of corn plants, can be converted to bio-derived monomers, such as cis, cis-Muconic Acid. The muconic acid can follow two pathways: Functional Replacements that can produce succinic acid and be turned into polyesters, resins, and composites that can which can be used in wind turbine blades, car parts, and snowboard; and Direct Replacements that can produce nylon and PET that can be used for clothing and plastic bottles.

Synthesis scheme for using muconic acid as a functional replacement versus direct replacements.

Plastic Upcycling

Recently, work funded by NREL’s Laboratory Directed Research and Development program has investigated methods of deconstructing the polymers in current plastic streams (e.g., polyethylene terephthalate and polystyrene) and converting them into value-added products. Work includes enzymatic degradation of plastics, incorporating reversible or biodegradable linkages into plastics, and repolymerization of recycled streams.

Education

  • Ph.D., Chemical and Biological Engineering, Colorado School of Mines, 2015

  • M.S., Chemical Engineering, Colorado School of Mines, 2013

  • B.S. in Chemical Engineering, Virginia Polytechnic Institute and State University, 2011

Professional Experience

  • Postdoctoral Researcher – Polymer Engineering, NREL, 2016–present

  • Graduate Intern, NREL, 2015–2016

  • Graduate Researcher, Colorado School of Mines, 2011–2015

  • Unit Operations Laboratory Instructor, Virginia Polytechnic Institute and State University, 2011

  • Undergraduate Research Associate, Virginia Polytechnic Institute and State University, 2009–2011

Patents

  1. "Renewable resins and unsaturated polyesters and methods of making the same," U.S. Patent Application No. 20170306085 (2017)

Featured Publications

  1.  "Characterization and engineering of a plastic-degrading aromatic polyesterase," PNAS (2018)

    Flow chart showing the enzymatic pathways for PET deconstruction by the PETase and MHETase enzymes into BHET, MHET, and TPA.

  2. "Biomass-derived monomers for performance-differentiated fiber reinforced polymer composites," Green Chemistry (2017)

    Lignocellulosic biomass can be converted to bio-derived monomers that can then be used to create 100 percent renewably sourceable fiber reinforced plastics.

  3. "Molecular-scale simulation of cross-flow migration in polymer melts," Physical Review E (2014)

    Visualization of migration in polymer processing flows shown with red, yellow, and blue squiggly lines.

  4. "Molecular scale simulation of homopolymer wall slip," Physical Review Letters (2013)

    Chart showing the dimensionless quantification of the degree of cross-flow migration for constant-shear and shear-gradient flows.
    Chart showing evidence of slip in entangled polymer flows as a result of shear banding and polymer disentanglement.

Additional Publications

  1. "Heterogeneous Diels-Alder catalysis for biomass-derived aromatic compounds," Green Chemistry (2017)

  2. "Renewable Unsaturated Polyesters from Muconic Acid," ACS Sustainable Chem. Eng. (2016)

  3. "Dynamic free energy surfaces for sodium diffusion in type II silicon clathrates," Physical Chemistry Chemical Physics (2016)

  4. "Cis,cis-Muconic acid: separation and catalysis to bio-adipic acid for nylon 6,6 polymerization," Green Chemistry (2016)

  5. "Effects of polydispersity on confined homopolymer melts: A Monte Carlo study," The Journal of Chemical Physics (2014)

  6. "Finding the Missing Physics: Mapping Polydispersity into Lattice-Based Simulations," Macromolecules (2014)

  7. "Parameter Free Prediction of Rheological Properties of Homopolymer Melts by Dynamic Monte Carlo Simulation," Macromolecules (2012)

  8. "The formation of hydrophobic films on silica with alcohols," Colloids and Surfaces A: Physicochemical and Engineering Aspects (2010)

Awards and Honors

  • U.S. Department of Energy Office of Science Graduate Student Research Award (2015)

  • American Chemical Society Excellence in Polymer Graduate Research Award (2015)

  • Society of Rheology Student Poster Competition Winner (2014)

  • Colorado School of Mines Research Symposium Best Department Presentation (2014)