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Poster: Dynamical properties of poly(lactic acid) stereoisomers

Bacova, Petra; Díaz González, Sheintly; Harmandaris, Vagelis; Molina, Sergio I.

Abstract

Poster presented at 10th International Discussion Meeting on Relaxations in Complex Systems (10thIDMRCS, https://10idmrcs.com/), which was held during July 20-25, 2025 at the Campus Diagonal-Besòs of the Universitat Politècnica de Catalunya-BarcelonaTech. Abstract: We present a computational investigation of the dynamical properties of poly(lactic acid) (PLA) and its stereoisomers, poly(L-lactic acid) (PLLA), poly(D-lactic acid) (PDLA), and copolymers of different composition (PDLLA), using systematic atomistic simulations. PLA, a biocompostable and biocompatible polymer, has garnered significant interest for its sustainable applications; however, its practical utility is often limited by its inherent dynamic characteristics. Understanding the segmental dynamics and glass transition temperature (Tg) of these stereoisomers is crucial for optimizing their processing and performance.Our simulations employed molecular dynamics techniques to explore the local motions within different PLA stereoisomers. We specifically focused on characterizing the segmental dynamics in connection with the local structure, which ultimately influence macroscopic properties such as degree of crystallinity and thus the amorphous or crystalline character of the PLA materials. By analyzing mean square displacements and correlation functions, we elucidated the distinct dynamic behaviors of PLLA, PDLA, and PDLLA. The simulations revealed dissimilar packing at molecular level between the stereoisomers [1], directly impacting their segmental mobility. Furthermore, we estimated the glass transition temperatures for each stereoisomer [2], demonstrating tendencies analogous to experimental observations. The results highlight the profound influence of stereoisomeric configuration on the dynamic properties of PLA, providing valuable insights for the design of novel PLA-based materials with tailored performance characteristics. This study underscores the power of atomistic simulations in unraveling complex polymer dynamics and guiding materials innovation. REFERENCES1. Petra Bačova, Vagelis Harmandaris, and Sergio I. Molina, Macromolecules 2025 58 (16), 8572-8580 https://pubs.acs.org/doi/full/10.1021/acs.macromol.5c009182. Sheintly K. Diaz Gonzalez, Computational study of biodegradable polymers with application in 3D printing, 2025, Master Thesis, University of Cádiz 10.5281/zenodo.17257116

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Dynamical properties of poly(lactic acid) stereoisomers P. Bačová1*, S. K. Díaz González1, V. Harmandaris2,3,4,S. I. Molina1 1Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias, IMEYMAT, Campus Universitario Río San Pedro s/n., Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain 2Computation-Based Science and Technology Research Center, The Cyprus Institute, Nicosia, Cyprus 3Department of Mathematics and Applied Mathematics, University of Crete, Heraklion, Crete, Greece 4 Institute of Applied and Computational Mathematics, Foundation for Research and Technology - Hellas, GR-71110 Heraklion, Crete, Greece *e-mail: [email protected] MOTIVATION GLASS TRANSITION TEMPERATURE FROM ATOMISTIC SIMULATIONS This research was funded by the European Union’s Horizon 2020 research and innovation program under Grant no. 810660 and under the Marie Skłodowska-Curie Horizon Europe action (grant agreement no. 101105208). Computing time granted from the GRNET S.A. in the National HPC facility ARIS under the project name SPASA and ESSPO is also acknowledged. This work was made possible through a fruitful collaboration with M. Maturi (UCA, Spain) and M. I. Asenjo Sanz (CFM-CSIC, San Sebastián, Spain). DSC AND MODULATED DSC SEGMENTAL RELAXATION FROM ATOMISTIC SIMULATIONS •Glass transition temperature and segmental relaxation time estimated for PLA samples of different molecular weight and stereochemistry by atomistic simulations and modulated differential scanning calorimetry •Molecular weight dependence of Tg follows the Flory-Fox relation •Segmental relaxation times show a very similar trend as Tg •Flory-Fox relation for copolymers seems to be valid only for low content of D-monomer CONCLUSIONS ACKNOWLEDGEMENTS REFERENCES [1] J. H. McAliley and D. A. Bruce, 7, 11, J. Chem. Theory Comput. , 3756–3767, 2011. [2] D. V. Guseva, A. A. Lazutin, and V. V. Vasilevskaya, Polymer, vol. 221, 123577, 2021. [3] A. D. Glova et al., Polym. Int., 65, 8, 892–898, 2016. [4] A. D. Glova et al., Macromolecules, 51, 2, 552–563, 2018. [5] M. Klajmon, V. Aulich, J. Ludik, and C. Cervinka, Ind. & Eng. Chem. Res., 62, 49, 2143721448, 2023. [6] P. A. Klonos, N. D. Bikiaris, P. Barmpalexis, and A. Kyritsis, Polymer, 305, 127177, 2024. EFFECT OF MOLECULAR WEIGHT: PLLA EFFECT OF STEREOCHEMISTRY •Study glass transition temperature (Tg) and segmental relaxation (τ) in poly(lactic acid) (PLA) stereoisomers: PLLA, PDLA and copolymers of different L and D content •Connect theoretical and experimental data to elucidate the structure-propertiesperformance relationship •Quick cooling from 190˚C to -20˚C (MDSC) and to -50˚C (DSC) to keep PLA amorphous SYSTEMS UNDER INVESTIGATION GPC in DMF, PS reference