Molecular scale analysis of the properties and toughening mechanism of polyethylene glycol modified epoxy asphalt

Abstract

Polyethylene glycol (PEG) with different chains was used to modify epoxy asphalt. Molecular models of PEG-modified epoxy asphalt were developed using molecular simulations (MS). The thermodynamic and mechanical properties of PEG-modified epoxy asphalt were analyzed, and its toughening mechanisms were explored. A method based on the Dijkstra algorithm was proposed to evaluate epoxy asphalt crosslinked networks. The results show that the introduction of PEG chains into epoxy asphalt can lower the glass transition temperature and enhance its toughness because of the extended length of the PEG chains, which can increase the free volume and improve the mobility of the epoxy resin in the epoxy asphalt. The crosslinked network quantitative evaluation method based on the Dijkstra algorithm can effectively evaluate the distribution of epoxy asphalt crosslinking bonds, providing further explanation of the toughening mechanism of PEG-modified epoxy asphalt. The feasibility of designing and screening epoxy asphalt materials by MS is verified, and a guide for toughening mechanism research of epoxy asphalt at the molecular level is provided.