Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling
Thermoplastic polyurethanes constitute a versatile family of materials with a broad variety of engineering applications. However, connection between their chemical structure and mechanical properties remains elusive, in large part due to their heterogeneous nature, arising from segregation of chemic...
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| Format: | Article |
| Language: | English |
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American Chemical Society (ACS)
2020
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| Online Access: | https://hdl.handle.net/1721.1/125804 |
| _version_ | 1811072452517691392 |
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| author | Lempesis, Nikolaos in ‘t Veld, Pieter J. Rutledge, Gregory C |
| author2 | Massachusetts Institute of Technology. Department of Chemical Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Chemical Engineering Lempesis, Nikolaos in ‘t Veld, Pieter J. Rutledge, Gregory C |
| author_sort | Lempesis, Nikolaos |
| collection | MIT |
| description | Thermoplastic polyurethanes constitute a versatile family of materials with a broad variety of engineering applications. However, connection between their chemical structure and mechanical properties remains elusive, in large part due to their heterogeneous nature, arising from segregation of chemically distinct segments into separate domains, with resulting complex morphologies. Using atomistic simulations, we examine the structure and mechanical properties of a common family of thermoplastic polyurethanes (TPU) comprising 4,4′-diphenylmethane diisocyanate and n-butanediol (hard segment) and poly(tetramethylene oxide) (soft segment). A lamellar stack model previously developed for the study of semicrystalline polymers is applied here for the first time to a phase-segregated copolymer. Equilibrium structure and properties were evaluated for TPUs with different ratios of hard and soft components, using a combination of Monte Carlo and molecular dynamics simulations. Stress-strain behaviors were then evaluated using nonequilibrium molecular dynamics (NEMD) simulations. The compositional dependence of the Young's moduli thus obtained is shown to be well-approximated by a micromechanical homogenization model of the hard and soft components. Voigt (upper) and Reuss (lower) bounds of modulus were obtained for orientationally averaged aggregates and shown to be greater than those measured experimentally. The discrepancy is explained in terms of the strain rate dependence of elastic moduli, characterized by an Eyring-like function. |
| first_indexed | 2024-09-23T09:06:11Z |
| format | Article |
| id | mit-1721.1/125804 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:06:11Z |
| publishDate | 2020 |
| publisher | American Chemical Society (ACS) |
| record_format | dspace |
| spelling | mit-1721.1/1258042022-09-30T13:26:35Z Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling Lempesis, Nikolaos in ‘t Veld, Pieter J. Rutledge, Gregory C Massachusetts Institute of Technology. Department of Chemical Engineering Thermoplastic polyurethanes constitute a versatile family of materials with a broad variety of engineering applications. However, connection between their chemical structure and mechanical properties remains elusive, in large part due to their heterogeneous nature, arising from segregation of chemically distinct segments into separate domains, with resulting complex morphologies. Using atomistic simulations, we examine the structure and mechanical properties of a common family of thermoplastic polyurethanes (TPU) comprising 4,4′-diphenylmethane diisocyanate and n-butanediol (hard segment) and poly(tetramethylene oxide) (soft segment). A lamellar stack model previously developed for the study of semicrystalline polymers is applied here for the first time to a phase-segregated copolymer. Equilibrium structure and properties were evaluated for TPUs with different ratios of hard and soft components, using a combination of Monte Carlo and molecular dynamics simulations. Stress-strain behaviors were then evaluated using nonequilibrium molecular dynamics (NEMD) simulations. The compositional dependence of the Young's moduli thus obtained is shown to be well-approximated by a micromechanical homogenization model of the hard and soft components. Voigt (upper) and Reuss (lower) bounds of modulus were obtained for orientationally averaged aggregates and shown to be greater than those measured experimentally. The discrepancy is explained in terms of the strain rate dependence of elastic moduli, characterized by an Eyring-like function. 2020-06-15T19:17:56Z 2020-06-15T19:17:56Z 2017-09 2017-08 2020-06-08T17:29:11Z Article http://purl.org/eprint/type/JournalArticle 0024-9297 1520-5835 https://hdl.handle.net/1721.1/125804 Lempesis, Nikolaos et al. "Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling." Macromolecules 50, 18 (September 2017): 7399–7409 © 2017 American Chemical Society en http://dx.doi.org/10.1021/acs.macromol.7b01296 Macromolecules Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Chemical Society (ACS) Prof. Rutledge via Ye Li |
| spellingShingle | Lempesis, Nikolaos in ‘t Veld, Pieter J. Rutledge, Gregory C Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title | Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title_full | Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title_fullStr | Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title_full_unstemmed | Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title_short | Atomistic Simulation of a Thermoplastic Polyurethane and Micromechanical Modeling |
| title_sort | atomistic simulation of a thermoplastic polyurethane and micromechanical modeling |
| url | https://hdl.handle.net/1721.1/125804 |
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