(692i) Advancing the Knowledge on Semicrystalline Polymers for Hydrogen Storage and Handling.

This presentation showcases some of the results of a project that focused at characterising, understanding and predicting the permeation of hydrogen in semicrystalline polymers suitable as liners for hydrogen tanks and pipelines. The mass transport in such systems is intimately related to the complex intercalation between the crystal and amorphous phases. A multiscale method was developed to represent the effect of the semicrystalline microstructure on the hydrogen sorption and diffusion in high-density polyethylene (HDPE) structures with tailored fraction of amorphous-crystalline connections (tie-chains). The gas sorption in the crystalline regions is negligible, and the confinement of the amorphous phase induces a significant increase of density and a drop in the sorption capacity. Adding ties between the crystal and the amorphous phase results in further densification, increase of the lamella tilt angle, and a decrease in the degree of crystallinity and hydrogen sorption coefficient, in agreement with several literature references. Results of the simulation are compared to data obtained at different pressures and temperatures on these materials. Indications on the key structural parameters that affect the barrier performance of the polymers are proposed.

This research forms part of the research program of DPI, 844: Modelling and Design of Multiphase Polymeric Materials for High Performance Applications Across Multiple Scales.

[1] ] O. Atiq, O., E. Ricci, M. Giacinti Baschetti, M.G. De Angelis, Modelling solubility in semi-crystalline polymers: a critical comparative review, Fluid Ph. Equilib., 556 (2022) 113412.
[2] Atiq, E. Ricci, M. Giacinti Baschetti, M.G. De Angelis, Multi-scale modeling of gas solubility in semi-crystalline polymers: bridging molecular dynamics with lattice fluid theory, Fluid Ph. Equilib. 570 (2023) 113798.
[3]O. Atiq, E. Ricci, M. Giacinti Baschetti, M.G. De Angelis, Molecular simulations of hydrogen sorption in semi-crystalline high-density polyethylene: the impact of the surface fraction of tie-chains, J. Phys. Chem. B. 128 (2024) 2799–2810.
[4] L. Merlonghi, O. Atiq, R. Rea, E. Mangano, A. Stroeks, M. Giacinti Baschetti, M.G. De Angelis, An experimental study of hydrogen sorption and permeation in high-performance polyamides, submitted to Int. J. Hydrogen Energy (2024)