Synthesis And Properties Of Fluore- Scent Waterborne Polyurethane Based On Carbazole And Its Derivate

Because of high sensitive and wide response range, fluorescence detecting technology was widely used in analytical chemistry, biochemistry, cell biology and some other fields. But fluorescent monomer has a poor solubility with matrix so it is easy to fall off the substrate, pollute the system and hold other defects, thus it is limited in medicine, biology and environmental science. While fluorescent polymer is macromolecule owns some fluorescent functional monomers connected by chemical bonds, it not only remains good optical properties of small molecules but also exhibits excellent processabilities. The polymer solves a series of problems of small molecule fluorescent substances, such as the inhomogeneous distribution of chromophores, the ineffectively control of the chromophores concentration and the chromophores easy to fall off the matrix during operating process, makes the fluorescent detecting technology a great improvement in scientific research and industrial application. It is an ideal matrix for waterborne polyurethane (WPU) to prepare fluorescent polymer, for the dispersing agent is water instead of volatile organic compounds (VOC), nonflammable, nontoxic, friendly to the environment, reliable and flexible, it also shows an excellent processing properties like solvent-based polyurethane.In order to prepare stable fluorescent waterborne polyurethane and broad the application areas of water-based polyurethane, two kinds of fluorescent monomers were designed and prepared based on 3-amino-9-ethylcarbazole and carbazole in this paper,2-[3-(9-ethylcarbazole)ureido]ethyl methacrylate (CUMA) and 9-(4-N,N-(2-hydroxyethyl)butyl)-9H-carbazole (HBC). We confirmed the molecular structure by Fourier Transform infrared spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The monomer concentration relationship versus absorbance value of CUMA and HBC were characterized by UV-visible absorption spectrum. The relationship between the fluorescence intensity and the compound concentration was obtained by fluorescence spectroscopy, at the same time, the affect by solvent on fluorescence intensity was discussed.In our work, to investigate the influence of fluorescent functional groups on the polyurethane systems, a series of purple fluorescent waterborne polyurethane dispersions were synthesized by step-growth addition polymerization. Firstly, we terminated polyurethane prepolymer with 2-hydroxyethyl acrylate (HEA), then reacted with CUMA by free radical polymerization. We can control the amount of functional groups in a certain range in our copolymers. In addition, another series of fluorescent WPU dispersions were obtained using isophorone diisocyanate (IPDI), polytetramethylene ether glycol (PTMG),2,2-dimethylol propionic acid (DMPA) with different ratios of HBC to 1,4-butanediol (BDO).The study indicated that the fluorescent WPU dispersions show emulsion stability and fluorescence stability. And the emulsion shows a polymer fluorescence enhancement effect when compares with the monomer. The fluorophore content impact on the average particle size, the thermal properties and water resistance has also been analyzed. This design concept also opens a window to produce high-performance functional waterborne polyurethane materials through the incorporation of some other novel functional monomers of low amounts. Such properties are promising for applications in areas such as polymeric fluorescent probe sensing, fluorescent sensors, drug carriers and organic photoconductors.