Preparation and Properties of Dynamic Disulfide Bond Self‑healing Polyurethane Modified Asphalt

In order to enhance the long‑term resistance to cracking of asphalt pavement,a self‑healing polyurethane modified asphalt based on dynamic disulfide bonds was developed. Polyurethane chain extender containing disulfide bonds(CY‑OA)was synthesized using cystamine dihydrochloride as raw material,and disulfide bond‑crosslinked polyurethane elastomer(PU‑SS)was synthesized through stepwise copolymerization. PU‑SS was mixed with asphalt to obtain self‑healing polyurethane modified asphalt(PSA). The physical and chemical properties,microscopic morphologies,and self‑healing properties of PU‑SS and PSA were studied. The results show that the addition of PU‑SS improves the low‑temperature deformation resistance of asphalt. The dynamic disulfide bond self‑healing mechanism of PU‑SS promotes the inherent self‑healing ability of asphalt,achieving synergistic repair. © 2024 Tongji University. All rights reserved.