Synthesis, Characterization, and Optical Performance of a Novel Fluorescent Waterborne Polyurethane

A fluorescent fluorescent waterborne polyurethane (FWPU) was synthesized by conjugating fluorescer, isodium 4,4′-bis[4-anilino-6-hydroxyethylamino-6-(2-choloronilino-1,3,5-triazin-2-yl)amino]stilbene-2,2′-disulphonate (RSW), into polyurethane backbone as a chain extender. The expected structure of FWPU was confirmed by Fourier transform infrared, 1H nuclear magnetic resonance, and UV−vis spectrophotometer, and the effect of fluorescer content, temperature, as well as quencher on the fluorescence performances of FWPU was investigated in detail. Results reveal that covalently conjugation has unconspicuous effect on optical performance, and FWPU shows similar fluorescence intensity to fluorescer RSW except for a red shift of about 10 nm in maximum absorption wavelengths. Further study finds that there is a positive correlation between the concentration of fluorescer and the fluorescence intensity of FWPU; however, the opposite effect is obtained when the concentration exceeds 1 × 10−5 mol/L, which is attributed to the concentration self-quenching. Although high temperature will decrease the intensity of fluorescence, the fluorescence components in FWPU shows high resistance to fluorescence quencher and thermal decomposition as a consequence of chemical combination with the polymer chain.