Characterization and molecular dynamics of interfacial adhesion in hydrogenated styrene/polyurethane prepolymer composite-modified asphalt

Abstract

To address the limitations of conventional polymer modified asphalt, a hydrogenated styrene block polyurethane prepolymer (M-PPU) modified asphalt was developed by incorporating a hydrogenated styrene block into a polyurethane prepolymer (PPU). The preparation process was first optimized, and the optimal modifier content was determined to be 4%, at which the modified asphalt exhibited improved penetration, softening point, ductility, and rotational viscosity. Fourier Transform Infrared Spectroscopy (FTIR) and Fluorescence Microscopy (FM) results showed that the modified asphalt possessed a denser and more stable internal structure. Thermogravimetric Analysis (TG) analysis demonstrated that the M-PPU modified asphalt exhibited approximately 9%–12% lower mass loss than unmodified asphalt in the temperature range of 0–455°C. Differential scanning calorimetry (DSC) results showed that the glass transition temperature increased by approximately 3–5°C, suggesting enhanced thermal stability of the asphalt system. Furthermore, molecular dynamics (MD) simulations indicated that M-PPU modified asphalt exhibited enhanced interfacial adhesion at the aggregate interface. This study provides a theoretical basis for the design and application of polyurethane-based composite-modified asphalt.