Synthesis, characterization and application of AFC-based waterborne polyurethane

A novel anionic AFC-based waterborne polyurethane was synthesized by importing the fluorescent agent 7-amino-4-(trifluoromethyl)coumarin (AFC) into the polyurethane chains. Structure of the WPU-AFC was confirmed by Fourier transform infrared spectroscopy (FTIR) and UV-visible absorption spectroscopy. Number average molecular weight and average emulsion particle size for WPU-AFC were also determined. It was found that the fluorescence intensity of WPU-AFC decreased with the increasing temperature and was enhanced compared with that of AFC. The improved thermal stability of WPU-AFC could be attributed to the incorporation of benzopyrone units in the preformed urethane groups. Furthermore, the fluorescence of WPU-AFC emulsion was very stable for long-term storage and it was a promising agent utilized in the specific collagen fiber materials.