Grants per year
Personal profile
Research Interests
Professor Torkelson’s group research motivation is driven by two main desires: (1) to understand at a fundamental level how molecular-scale behavior of polymers relates to macroscale properties; and (2) and to engineer and optimize those polymer properties by tuning molecular-scale responses via dynamic chemistry, nanoscale confinement, chain architecture, and novel solid-state processing, among other methods. For example, the group has recently developed three simple dynamic chemistry approaches that allow for spent thermosets or crosslinked polymers to be recycled by melt-state processing into new crosslinked polymer products with full recovery of crosslink density and associated properties.
They are also developing a deeper understanding of how nanoscale confinement of polymers in thin films or in nanocomposites can lead to major changes in properties, including glass transition temperature (which can change by 50 degrees C or more), physical aging, stiffness or modulus, and diffusion, among others. In support of our research efforts, we have developed simple non-destructive characterization tools that allow us to characterize the gradient in behavior from a free surface or substrate/nanofiller. They are also doing fundamental research to understand how polymer architecture (e.g., cyclic or ring polymers, stars, hyperbranched polymers, brushes, bottlebrushes, etc.) and copolymer structure can modify the bulk and nanoconfined behaviors of polymers. In turn, we are using that understanding to engineer materials for improved performance. Finally, they are also pursuing novel, industrially scalable solid-state processing approaches to design and produce modified polymers, polymer blends, composites, and nanocomposites that cannot be produced by conventional melt-state processing. Their process is the solid-state analog of twin-screw extrusion and allows for much greater work to be done on the polymeric materials during processing. As a result, their solid-state process achieves dispersion levels as well as chemistries that are not attainable with melt-state processing methods.
Education/Academic qualification
Chemical Engineering, PhD, University of Minnesota
… → 1983
Chemical Engineering, BS, University of Wisconsin-Madison
… → 1978
Research interests
- Nanoscience and nanotechnology
- Polymer science and engineering
- Sustainability
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Grants
- 71 Finished
Direct Measurement of the Role of Confinement and Chemistry on Local Physical and Mechanical Properties of Polymers
Brinson, L. C., Putz, K. W. & Torkelson, J. M.
9/1/12 → 8/31/16
Project: Research project
MRSEC: Multifunctional Nanoscale Material Structures
Chang, R. P. H., Olvera de la Cruz, M. & Torkelson, J. M.
10/1/05 → 7/31/12
Project: Research project
Facilities: MRSEC: Multifunctional Nanoscale Material Structures
Olvera de la Cruz, M. & Torkelson, J. M.
10/1/05 → 7/31/12
Project: Research project
MRSEC: Multifunctional Nanoscale Material Structures
Mason, T. O., Olvera de la Cruz, M. & Torkelson, J. M.
10/1/05 → 7/31/12
Project: Research project
MRSEC: Multifunctional Nanoscale Material Structures
Olvera de la Cruz, M., Poeppelmeier, K. & Torkelson, J. M.
10/1/05 → 7/31/12
Project: Research project
Research Output
Biobased Reprocessable Polyhydroxyurethane Networks: Full Recovery of Crosslink Density with Three Concurrent Dynamic Chemistries
Hu, S., Chen, X. & Torkelson, J. M., Jun 3 2019, In : ACS Sustainable Chemistry and Engineering. 7, 11, p. 10025-10034 10 p.Research output: Contribution to journal › Article
6
Scopus
citations
Isolating the effect of polymer-grafted nanoparticle interactions with matrix polymer from dispersion on composite property enhancement: The example of polypropylene/halloysite nanocomposites
Wei, T., Jin, K. & Torkelson, J. M., Aug 2 2019, In : Polymer. 176, p. 38-50 13 p.Research output: Contribution to journal › Article
Recyclable polymer networks containing hydroxyurethane dynamic cross-links: Tuning morphology, cross-link density, and associated properties with chain extenders
Chen, X., Li, L. & Torkelson, J. M., Sep 12 2019, In : Polymer. 178, 121604.Research output: Contribution to journal › Article
4
Scopus
citations
Reprocessable Polyhydroxyurethane Network Composites: Effect of Filler Surface Functionality on Cross-link Density Recovery and Stress Relaxation
Chen, X., Li, L., Wei, T., Venerus, D. C. & Torkelson, J. M., Jan 16 2019, In : ACS Applied Materials and Interfaces. 11, 2, p. 2398-2407 10 p.Research output: Contribution to journal › Article
16
Scopus
citations
Reprocessable Polymer Networks Designed with Hydroxyurethane Dynamic Cross-links: Effect of Backbone Structure on Network Morphology, Phase Segregation, and Property Recovery
Chen, X., Li, L., Wei, T. & Torkelson, J. M., Jul 1 2019, In : Macromolecular Chemistry and Physics. 220, 13, 1900083.Research output: Contribution to journal › Article
6
Scopus
citations