TY  - EJOU
AU  - Gong, Sai 
AU  - Xiang, Shanglin 
AU  - Wang, Tingwei 
AU  - Cai, Dongyu 

TI  - Towards Solar-Driven Formation of Robust and Self-Healable Waterborne Polyurethane Containing Disulfide Bonds via <i>in-situ</i> Incorporation of 2D Titanium Carbide MXene
T2  - Journal of Renewable Materials

PY  - 2023
VL  - 11
IS  - 3
SN  - 2164-6341

AB  - 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 <i>in-situ</i> 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/cm<sup>2</sup>) 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%.
KW  - MXene; waterborne polymer; photothermal conversion; film formation

DO  - 10.32604/jrm.2022.023011