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 Twin Cities
… → 1983
Chemical Engineering, BS, University of Wisconsin-Madison
… → 1978
Research interests keywords
- Nanoscience and nanotechnology
- Polymer science and engineering
- Sustainability
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Collaborations and top research areas from the last five years
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ResIn: Responsible Innovation for Highly Recyclable Plastics
Broadbelt, L. J., Dunn, J. B. & Torkelson, J. M.
10/1/19 → 3/31/24
Project: Research project
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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
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Torkelson subproject, Material Computational Framework and Enhancement for Tire Property Design
Goodyear Tire & Rubber Company
1/1/11 → 12/31/12
Project: Research project
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MRSEC: Multifunctional Nanoscale Material Structures
Nguyen, S., Olvera de la Cruz, M. & Torkelson, J. M.
10/1/05 → 9/30/11
Project: Research project
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MRSEC: Multifunctional Nanoscale Material Structures
Marks, T. J., Olvera de la Cruz, M., Torkelson, J. M., Olvera de la Cruz, M. & Torkelson, J. M.
10/1/05 → 7/31/12
Project: Research project
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Biobased, Reprocessable Non-isocyanate Polythiourethane Networks with Thionourethane and Disulfide Cross-Links: Comparison with Polyhydroxyurethane Network Analogues
Chen, Y., Chen, B. & Torkelson, J. M., May 23 2023, In: Macromolecules. 56, 10, p. 3687-3702 16 p.Research output: Contribution to journal › Article › peer-review
1 Scopus citations -
Novel covalent adaptable networks (CANs) of ethylene/1-octene copolymers (EOCs) made by free-radical processing: comparison of structure-property relationships of EOC CANs with EOC thermosets
Chen, B., Fenimore, L. M., Chen, Y., Barbon, S. M., Brown, H. A., Auyeung, E., Shan, C. L. P. & Torkelson, J. M., Jul 19 2023, In: Polymer Chemistry. 14, 31, p. 3621-3637 17 p.Research output: Contribution to journal › Article › peer-review
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Rapidly synthesized, self-blowing, non-isocyanate polyurethane network foams with reprocessing to bulk networks via hydroxyurethane dynamic chemistry
Purwanto, N. S., Chen, Y., Wang, T. & Torkelson, J. M., Apr 17 2023, In: Polymer. 272, 125858.Research output: Contribution to journal › Article › peer-review
5 Scopus citations -
Reducing the Bulk Fragility and Suppressing the Fragility-Confinement Effect in Polystyrene with Very Low Levels of 2-Ethylhexyl Acrylate Comonomer
Wang, T., Peera, A., Reffner, J. & Torkelson, J. M., May 23 2023, In: Macromolecules. 56, 10, p. 3527-3537 11 p.Research output: Contribution to journal › Article › peer-review
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Reprocessable, Bio-Based, Self-Blowing Non-Isocyanate Polyurethane Network Foams from Cashew Nutshell Liquid
Purwanto, N. S., Chen, Y. & Torkelson, J. M., Aug 11 2023, In: ACS Applied Polymer Materials. 5, 8, p. 6651-6661 11 p.Research output: Contribution to journal › Article › peer-review
1 Scopus citations