Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach
We investigate the molecular dynamics of glycolide/lactide/caprolactone (Gly/Lac/Cap) copolymers using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), <sup>1</sup>H second-moment, <sup>1</sup>H spin-lattice relaxation time (T<sub>...
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2025-03-01
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| author | Alovidin Nazirov Jacek Klinowski John Nobleman |
| author_facet | Alovidin Nazirov Jacek Klinowski John Nobleman |
| author_sort | Alovidin Nazirov |
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| description | We investigate the molecular dynamics of glycolide/lactide/caprolactone (Gly/Lac/Cap) copolymers using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), <sup>1</sup>H second-moment, <sup>1</sup>H spin-lattice relaxation time (T<sub>1</sub>) analysis, and <sup>13</sup>C solid-state NMR over a temperature range of 100–413 K. Activation energies and correlation times of the biopolymer chains were determined. At low temperatures, relaxation is governed by the anisotropic threefold reorientation of methyl (-CH<sub>3</sub>) groups in lactide. A notable change in T<sub>1</sub> at ~270 K and 294 K suggests a transition in amorphous phase mobility due to translational diffusion, while a second relaxation minimum (222–312 K) is linked to CH<sub>2</sub> group dynamics influenced by caprolactone. The activation energy increases from 5.9 kJ/mol (methyl motion) to 22–33 kJ/mol (segmental motion) as the caprolactone content rises, enhancing the molecular mobility. Conversely, lactide restricts motion by limiting rotational freedom, thereby slowing global dynamics. DSC confirms that increasing ε-caprolactone lowers the glass transition temperature, whereas higher glycolide and lactide content raises it. The onset temperature of main-chain molecular motion varies with the composition, with greater ε-caprolactone content enhancing flexibility. These findings highlight the role of composition in tuning relaxation behavior and molecular mobility in copolymers. |
| format | Article |
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| language | English |
| publishDate | 2025-03-01 |
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| spelling | doaj-art-0e3959cf95204792b0ebde13d4a7221a2025-08-20T02:06:12ZengMDPI AGMolecules1420-30492025-03-01305117510.3390/molecules30051175Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique ApproachAlovidin Nazirov0Jacek Klinowski1John Nobleman2Department of Macromolecular Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, PolandDepartment of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UKNatural Science Department, LaGuardia Community College, City University of New York, 31-10 Thomson Ave, Long Island City, NY 11101, USAWe investigate the molecular dynamics of glycolide/lactide/caprolactone (Gly/Lac/Cap) copolymers using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), <sup>1</sup>H second-moment, <sup>1</sup>H spin-lattice relaxation time (T<sub>1</sub>) analysis, and <sup>13</sup>C solid-state NMR over a temperature range of 100–413 K. Activation energies and correlation times of the biopolymer chains were determined. At low temperatures, relaxation is governed by the anisotropic threefold reorientation of methyl (-CH<sub>3</sub>) groups in lactide. A notable change in T<sub>1</sub> at ~270 K and 294 K suggests a transition in amorphous phase mobility due to translational diffusion, while a second relaxation minimum (222–312 K) is linked to CH<sub>2</sub> group dynamics influenced by caprolactone. The activation energy increases from 5.9 kJ/mol (methyl motion) to 22–33 kJ/mol (segmental motion) as the caprolactone content rises, enhancing the molecular mobility. Conversely, lactide restricts motion by limiting rotational freedom, thereby slowing global dynamics. DSC confirms that increasing ε-caprolactone lowers the glass transition temperature, whereas higher glycolide and lactide content raises it. The onset temperature of main-chain molecular motion varies with the composition, with greater ε-caprolactone content enhancing flexibility. These findings highlight the role of composition in tuning relaxation behavior and molecular mobility in copolymers.https://www.mdpi.com/1420-3049/30/5/1175glycolidelactidecaprolactonebiopolymermolecular dynamicsrelaxation spectroscopy |
| spellingShingle | Alovidin Nazirov Jacek Klinowski John Nobleman Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach Molecules glycolide lactide caprolactone biopolymer molecular dynamics relaxation spectroscopy |
| title | Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach |
| title_full | Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach |
| title_fullStr | Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach |
| title_full_unstemmed | Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach |
| title_short | Comparative Analysis of Amorphous and Biodegradable Copolymers: A Molecular Dynamics Study Using a Multi-Technique Approach |
| title_sort | comparative analysis of amorphous and biodegradable copolymers a molecular dynamics study using a multi technique approach |
| topic | glycolide lactide caprolactone biopolymer molecular dynamics relaxation spectroscopy |
| url | https://www.mdpi.com/1420-3049/30/5/1175 |
| work_keys_str_mv | AT alovidinnazirov comparativeanalysisofamorphousandbiodegradablecopolymersamoleculardynamicsstudyusingamultitechniqueapproach AT jacekklinowski comparativeanalysisofamorphousandbiodegradablecopolymersamoleculardynamicsstudyusingamultitechniqueapproach AT johnnobleman comparativeanalysisofamorphousandbiodegradablecopolymersamoleculardynamicsstudyusingamultitechniqueapproach |