Synthesis and Characterization of Healable Waterborne Polyurethanes with Cystamine Chain Extenders

• Main Authors: Dae-Il Lee, Seung-Hyun Kim, Dai-Soo Lee
• Format: Article
• Language: English
• Published: MDPI AG 2019-04-01
• Series: Molecules
• Subjects: waterborne polyurethane; self-healing; cystamine; disulfide; metathesis
• Online Access: https://www.mdpi.com/1420-3049/24/8/1492

In this study, environmentally friendly, self-healing waterborne polyurethanes (WPUs) were prepared based on the disulfide metathesis reaction in cystamine. The cystamine acted as a chain extender in the WPU film, which showed a high mechanical strength of 19.1 MPa. The possibility of self-healing reaction was simultaneously modeled via liquid chromatography–mass spectrometry (LC-MS). WPU was confirmed to self-heal a surface crack thermally after a scratch test, and the efficiency was measured by comparing the mechanical properties before and after a cut-and-healing test. In addition, the disulfide-thiol exchange reaction was confirmed to occur in WPU with cystamine as a chain extender and 2-mercaptoethanol. Hot press tests confirmed the possibility of reprocessing the WPU. The WPU incorporating disulfide groups showed great potential as a smart self-healing material.