Matte waterborne polyurethane fabric nanocoating with versatility via mono-layered montmorillonite nanosheets

With the change of people's aesthetic concepts, low-gloss coatings are becoming a new hotspot of interest. However, the low-gloss waterborne polyurethane (WPU) coatings reported by others to our knowledge are all single-functional coatings, which are difficult to meet the requirements of complex application environments. Herein, a series of low-gloss WPU nanocoatings with versatility via mono-layered organic montmorillonite (OMt) nanosheets is reported, and then applied to polyester fabric. Ultraviolet-visible (UV-vis) examination indicated that the OMt nanosheets made the as-prepared nanocoatings have unique UV-shielding performance. Thermogravimetric analysis (TGA) curves showed that the OMt nanosheets increased the thermal stability of the nanocoatings. Moreover, Fourier transforms infrared (FTIR) spectroscopy confirmed the existence of hydrogen bonds between OMt nanosheets and WPU molecular chains, which is the essential reason why the nanocoating had a matte level of 60 degrees gloss of 1.9 GU on the fabric. Rougher surface topography of the nanocoating compared with pristine WPU coating and fabric observed by scanning electron microscopy (SEM) is the direct reason for the decrease in gloss. In addition, the influence of the times of scraping on the gloss of the coatings was also studied. Thus, our research may provide new insights for the multifunctional matte WPU coatings.

Automated summary

This study reported a series of low-gloss WPU nanocoatings prepared using OMt nanosheets, applied to polyester fabric, with unique UV-shielding performance and increased thermal stability. Hydrogen bonds between OMt nanosheets and WPU molecular chains were identified as the key factor for the matte level of the coating, while the rough surface of the nanocoating directly led to the decrease in gloss.