Open Access

ARTICLE

Towards Solar-Driven Formation of Robust and Self-Healable Waterborne Polyurethane Containing Disulfide Bonds via in-situ Incorporation of 2D Titanium Carbide MXene

by Sai Gong^1,2,#, Shanglin Xiang^1,#, Tingwei Wang^1,*, Dongyu Cai^2,*

1 College of Materials Science & Engineering, Nanjing Tech University, Nanjing, 211816, China
2 Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing, 211816, China

* Corresponding Authors: Tingwei Wang. Email: ; Dongyu Cai. Email:
# These authors make equal contribution to this work

Journal of Renewable Materials 2023, 11(3), 1063-1076. https://doi.org/10.32604/jrm.2022.023011

Received 05 April 2022; Accepted 13 June 2022; Issue published 31 October 2022

Abstract

Waterborne polymers are vital for coating industry to reduce carbon emissions. However, formation of robust and self-healable films at ambient temperature remains a challenge owing to high energy cost of film formation process. This work reports a solar-driven film formation of waterborne polyurethanes (WPUs) containing disulfide bonds via in-situ incorporation of 2D titanium carbide (MXene) with ability to convert light to heat. Instead of directly mixed with WPUs, MXene is added to join the reaction with isocyanate-terminated pre-polymer before emulsification process. This approach not only prevents aggregation of MXene in water but stabilizes MXene against thermal degradation which is the key hurdle for mass production of MXene/WPU composites. More importantly, our results show that mechanical performance of WPU films under visible light (100 mW/cm²) is overwhelmingly competitive with that processed in oven. Furthermore, the existence of disulfide bonds in PU chains enables fast self-healing of micro-cracks under natural visible light which could vanish completely within 40 min. The fractured specimens were repaired under natural visible light for 2 h, and the self-healing efficiency of tensile strength and elongation at break reached over 94.00%.

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