Effect and Enhancement Mechanism of Silane Coupling Agent Modified Fly Ash Cenospheres on the Mechanical and Tribological Properties of Epoxy Composites

ABSTRACT Considering that silane coupling agent modified fly ash cenospheres (FACs) play an important role in improving the performance of epoxy resin (EP) composite coatings, three silane coupling agents (KH550, KH602, and KH792) were studied to modify FACs and enhance the performance of EP composite coatings. The structure and morphology of the different fillers and EP composites were characterized by Fourier transform infrared and scanning electron microscopy. The tribological properties of EP composite coatings were studied by using a multi‐functional friction and wear testing machine. The results show that the mechanical and tribological properties of EP composites with 3 wt.% filler content are the best when the coupling agent is the same. The 3 wt.% KH792‐FACs/EP composite has the highest tensile strength (63.7 MPa) and modulus (837.8 MPa), and the lowest friction coefficient (0.074) and wear rate (0.46 × 10 −9 cm 3 /Nm). Molecular dynamics simulations reveal that the KH792‐FACs/EP complex exhibits the highest interaction potential energy (3803.77 kcal/mol) and glass transition temperature (340.31 K), along with the lowest free energy of formation (5.23%) and diffusion coefficient D (4.4 × 10 −5 Å 2 /ps). Therefore, molecular dynamics is beneficial to the selection and development of coupling agents and the design of EP composite coatings.