Covalent Deposition of Diels–Alder Reaction on Polyester Fiber Surface and Its Enhancement Mechanism on <scp>SBS</scp>‐Modified Asphalt

ABSTRACT Polyester (PET) fibers offer excellent chemical stability, mechanical strength, and high‐temperature tolerance, making them promising for asphalt applications. However, their smooth, chemically inert surface limits interfacial bonding with asphalt, reducing the overall performance. To address this, a mild covalent deposition method was employed, utilizing a polydopamine and furfuryl amine crosslinking reaction to incorporate furan groups on PET fibers. This enabled the formation of a dense Diels–Alder (D–A) reactive crosslinking layer. Characterization revealed that this layer increased surface roughness, free energy, and active functional groups, improving wetting and interlocking with asphalt. Rheological tests showed enhanced performance in styrene–butadiene–styrene (SBS)‐modified asphalt composites, with a 7.73% increase in G * at 46°C and an 81.94% improvement in adhesion. Molecular dynamics simulations confirmed the enhanced interfacial interactions between DA‐PET fibers and SBS‐modified asphalt, providing insight into the mechanism behind the improvements. This study presents a novel approach for optimizing PET fiber performance in asphalt materials.