Dual dynamic bonds approach for polyurethane recycling and self-healing of emulsified asphalt

Kuiling Wei; Yan Wu; Xuejuan Cao; Xiaoyu Yang; Boming Tang; Bailin Shan

doi:10.1016/j.scitotenv.2023.163915

Dual dynamic bonds approach for polyurethane recycling and self-healing of emulsified asphalt

Sci Total Environ. 2023 Aug 10:885:163915. doi: 10.1016/j.scitotenv.2023.163915. Epub 2023 May 5.

Authors

Kuiling Wei¹, Yan Wu², Xuejuan Cao³, Xiaoyu Yang⁴, Boming Tang⁵, Bailin Shan¹

Affiliations

¹ School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China.
² School of Material Science and Engineering, Chongqing Jiaotong University, Chongqing 400074, China. Electronic address: dr.w@mails.cqjtu.edu.cn.
³ School of Material Science and Engineering, Chongqing Jiaotong University, Chongqing 400074, China; National and Local Joint Engineering Research Center of Transportation and Civil Engineering Materials, Chongqing Jiaotong University, Chongqing 400074, China.
⁴ School of Traffic and Transportation, Chongqing Jiaotong University, Chongqing 400074, China.
⁵ School of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, China; National and Local Joint Engineering Research Center of Transportation and Civil Engineering Materials, Chongqing Jiaotong University, Chongqing 400074, China.

PMID: 37149186
DOI: 10.1016/j.scitotenv.2023.163915

Abstract

To recycle polyurethane and extend the service life of polyurethane-modified emulsified asphalt, this study developed novel perspectives for a lower carbon-footprint and cleaner preparation of recyclable polyurethane (RWPU) and its modified emulsified asphalt (RPUA-x) by using self-emulsification and dual dynamic bonds. Particle dispersion and zeta potential tests reflected that the emulsions of RWPU and RPUA-x existed excellent dispersion and storage stability. Microscopic and thermal analyses indicated that RWPU possessed dynamic bonds and maintained thermal stability below 250 °C as anticipated. Concurrently, RWPU provided RPUA-x with a strong physical cross-linking network, and a homogeneous phase was observed in RPUA-x after drying. Self-healing and mechanical evaluation results revealed that the regeneration efficiencies of RWPU were 72.3 % (stress) and 100 % (strain), respectively, and the stress-strain healing efficiency of RPUA-x was >73 %. The energy dissipation performance and plastic damage principle of RWPU were investigated using cyclic tensile loading. The multiple self-healing mechanisms of RPUA-x were revealed through microexamination. Furthermore, the viscoelasticity of RPUA-x and variations in flow activation energy were determined based on Arrhenius fitting from dynamic shear rheometer tests. In conclusion, disulfide bonds and hydrogen bonds endow RWPU with remarkable regenerative properties and grant RPUA-x with both asphalt diffusion self-healing and dynamic reversible self-healing capabilities.

Keywords: Disulfide bonds; Emulsified asphalt; Hydrogen bonds; Recyclable polyurethane; Self-healing.