Dynamics interaction in highly stretchable EGMEA-g-ENR-LiTFSI systems: Insights from molecular interactions via real time Raman and DFT analysis

Improving the properties of natural rubber (NR) for advanced applications remains a critical challenge, particularly in achieving enhanced mechanical, thermal and ionic conductivity properties. Here, ethylene glycol methyl ether acrylate-grafted epoxidized natural rubber with lithium bis(trifluoromethanesulfonyl)imide (EGMEA-g-ENR-LiTFSI) was synthesized via a UV-curing process, significantly reducing solvent usage and preparation time. A comprehensive investigation combining experimental and computational approaches was performed to optimize material properties. Analytical techniques, including in situ Raman spectroscopy, FTIR, TGA, DSC, XRD, electrochemical analysis and density functional theory (DFT) simulations were employed to evaluate the material properties. The Raman spectra exhibited significant alterations in molecular structure, offering critical insights into the grafting reactions and facilitating a deeper understanding of the electrochemical behaviour of the system. Furthermore, DFT analysis provide insights into the molecular interactions between lithium salts and rubber-based polymer matrix, complementing experimental findings. The results demonstrated enhanced polymer-salt interactions, suppression of crystallinity, and improved ionic conductivity and thermal stability in the rubber-based polymer. In particular, we demonstrate both the applicability and limitations of the epoxide group in ENR, providing key insights for improving the stability and performance of the material.