Deciphering van der Waals interaction between polypropylene and carbonated fly ash from experimental and molecular simulation

Pollution emitted from power plants, including a considerable amount of fly ash (FA) and carbon dioxide (CO₂), annually increases and is challenging from an environmentally friendly and sustainable point of view. To date, laboratory-scaled approaches cannot efficiently replace the FA-landfilling and mitigate the stress from CO₂ emission. Here, a practically operatable fundamental work by combining carbonated FA (C-FA)-immobilizing CO₂ in FA-and polypropylene (PP) matrix is reported and reveals abnormal mechanical and thermal features clarified by calculating van der Waals (vdW) interaction from an atomic scale. This is the first study wherein the interaction between instantaneous dipole moment-induced PP and fillers is simulated and examined. The vdW interactions at the (hetero)interfaces are -59.66, -82.30, and -224.39 kJ mol^-1 Å^-2 for PP, calcium oxide (CaO; before carbonation), and calcium carbonate (CaCO₃; after carbonation), respectively, which provides concrete theoretical support for interesting findings such as the independence of tensile strength on filler loadings and "well-grown" interface-induced higher conductivity characteristics of the composites. Therefore, this work can offer practical solutions to mitigate pollution, provide a new perspective on fundamental physical interactions, and guide the development of practical next-generation composite materials.