Synthesis and fluorescent investigations of VBL-based waterborne polyurethane dye

Fluorescent brightening agent VBL-based waterborne polyurethane dye (VBL-WPU) was synthesized by incorporation of VBL into waterborne polyurethane chains. The expected structure of polymeric fluorescent brightening agent was confirmed by FT-IR and UV-vis spectra. The molecular weight, average particle sizes and the contents of VBL segments in VBL-WPU were investigated. This polymeric dye exhibited intriguing optical behaviors. The absorption and emission maxima of VBL-WPU showed obviously hypsochromic shift in comparison with those of VBL. The fluorescence intensity of the polymer was prominently enhanced comparing with VBL because of the changes of micro-circumstance of VBL. Furthermore, the fluorescence of VBL-WPU was not sensitive to hydroquinone quencher. (C) 2011 Elsevier B.V. All rights reserved.