Abstract
Polylactide-block-poly(γ-methyl-ϵ-caprolactone)-block-polylactide (LML) is a sustainable thermoplastic elastomer (TPE) candidate that exhibits competitive mechanical properties as compared to traditional styrenic TPEs. The relatively low glass transition temperature of the polylactide endblocks, however, results in stress relaxation and low levels of elastic recovery. We report the synthesis and characterization of poly(γ-methyl-ϵ-caprolactone) (PMCL) and LML end-functionalized with ureidopyrimidinone (UPy) hydrogen-bonding moieties to improve the elastic performance of these polymers. Although UPy-functionalized PMCL shows dynamical mechanical behavior that is distinct from the unfunctionalized homopolymer, it does not exhibit elastomeric behavior at room temperature. The addition of UPy endgroups to LML increases the ultimate tensile strength, elongation at break, and tensile toughness compared to unfunctionalized LML. Stress relaxation studies at a fixed strain show reduced levels of stress relaxation in LML with UPy endgroups. The stress relaxation was further reduced by including semicrystalline poly((S,S)-lactide) as endblocks with UPy endgroups.
Original language | English (US) |
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Pages (from-to) | 2598-2609 |
Number of pages | 12 |
Journal | Biomacromolecules |
Volume | 20 |
Issue number | 7 |
DOIs | |
State | Published - Jul 8 2019 |
Bibliographical note
Funding Information:We would like to acknowledge Bongjoon Lee for obtaining the TEM images and Nicholas Hampu for collecting SAXS data. Cecilia Hall, Michael Larsen, and Ingrid Haugan Smidt are acknowledged for many helpful discussions. We thank Ortec, Inc. for generously providing lactide used in these studies. SAXS experiments were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by the Northwestern University, E.I. DuPont de Nemours & Co. and Dow Chemical Company. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by the Argonne National Laboratory under contract no. DE-AC02-06CH11357. Data was collected using an instrument funded by the National Science Foundation under award no. 0960140.
Funding Information:
This work was funded by the Center for Sustainable Polymers, an NSF-supported Center for Chemical Innovation (CHE-1413862) headquartered at the University of Minnesota.
Funding Information:
We would like to acknowledge Bongjoon Lee for obtaining the TEM images and Nicholas Hampu for collecting SAXS data. Cecilia Hall, Michael Larsen, and Ingrid Haugan Smidt are acknowledged for many helpful discussions. We thank Ortec, Inc. for generously providing lactide used in these studies. SAXS experiments were performed at the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by the Northwestern University, E.I. DuPont de Nemours & Co., and Dow Chemical Company. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science user facility operated for the DOE Office of Science by the Argonne National Laboratory under contract no. DE-AC02-06CH11357. Data was collected using an instrument funded by the National Science Foundation under award no. 0960140.
Publisher Copyright:
© 2019 American Chemical Society.