Investigation of Compatibility and Interaction Mechanisms in Rubber‐Plastic Modified Asphalt System: Experimental Characterization and Molecular Simulation

ABSTRACT To fundamentally overcome the challenges of poor compatibility and low‐temperature performance in plastic‐modified asphalt, this study proposes an innovative strategy by developing a novel thermoplastic elastomer (TPE) via twin‐screw extrusion of low Mooney viscosity desulfurized reclaimed rubber (LMMR), polyethylene plastics, and the compatibilizer SEBS‐g‐MAH. This approach distinguishes itself from previous studies utilizing conventional GTR or simple blends by achieving superior molecular‐level compatibility and a stable “core‐shell” structure. The purpose of this study is to explore the compatibilization mechanism of different plastic and rubber types on the storage stability of rubber‐plastic‐based TPE modified asphalt, including rheological behavior, storage stability, microscopic characterization, and molecular dynamics simulation. Results showed that the low Mooney viscosity desulfurized reclaimed rubber (LMMR) based TPE‐modified asphalt demonstrates excellent storage stability and low‐temperature performance. Multi‐scale characterization indicated that the compatibilizer breaks polymer intermolecular forces and promotes two‐phase interface fusion in the rubber‐plastic system, ensuring the uniform distribution at the interface layer. The three‐dimensional network structure enhances storage stability and improves the low‐temperature performance of rubber‐plastic modified asphalt. Molecular dynamics simulation further confirmed that LMMR‐based TPE‐modified asphalt could enhance the interaction energy among mixed‐system components, improve diffusion uniformity, strengthen short‐range intermolecular interactions, and lead to significantly optimized components. This study provided a theoretical foundation and scientific guidance for exploring the compatibility mechanisms of waste rubber‐modified asphalts and their engineering applications.