Preparation Of Cationic Fluorescent Dye And The Study Of Their Application

One new cationic fluorescent dye4,4’-((1E,1’E)-1,4-phenylenebis(ethene-2,1-diyl))-bis(1-ethylpyridin-1-ium) bromide (DPPB) was synthesized and characterizedby infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectrometer (NMR).Meanwhile, other two D--A type cationic fluorescent dyes were synthesized, and theywere (E)-4-(4-(diethylamino)styryl)-1-ethylpyridin-1-ium bromide (DHEASPBr-C2)and (E)-4-(4-(diethylamino)styryl)-1-butylpyridin-1-ium bromide (DHEASPBr-C4).Their fluorescence and dyeing properties have been investigated. On the one hand,spinning solution was prepared through blending the dye and the fiber polymer. on theother hand, spinning solution was the solution of fluorescent polymer when thechromophore was grafted to the fiber polymer skeleton via chemical method. Finally,the fluorescent nanofibers could be prepared through electrospinning process.The main contents in the dissertation are as follows: DPPB was characterized byinfrared spectroscopy and nuclear magnetic resonance spectrometer. Secondly, dye’sUV-Vis absorption spectra and single-photon emission fluorescence spectra werestudied by. Thirdly, several fluorescent dyes were used as cationic dyes to preparefluorescent acrylic fabrics, and the dyeing kinetics and other dyeing properties werediscussed. Such as, Sorption rates, Building-up properties, color fastness andfluorescent effect. Fourthly, copolymer Acrylonitrile-Acrylic (P(AN-co-AA)) andfluorescent copolymer were synthesized successfully. Also these copolymers were usedto prepare nanofibers through electrospinning process and the preparation methods forspinning solution were physical blending method and fluorescent copolymer dissolvingmethod, respectively. Finally some typical properties of the nanofibers were tested. suchas, infrared spectroscopy, the morphology, thermal properties and fluorescenceproperties.Result showed that: (1) Fluorescent dyes(DPPB, DHEASPBr-C2and DHEASPBr-C4) were synthesizedsuccessfully. The reaction process of DPPB was relatively simple and is ease to be usedin industrial production, which provides a new approach for the industrial production offluorescent dye.(2) DPPB could be efficiently excited by near UV light (384nm) and exhibited anintense yellow luminescence at469nm. Compared with the dyes which are D--A class,maximum absorption and emission wavelengths of DPPB were small thanDHEASPBr-C2and DHEASPBr-C4, but the fluorescence intensity was much larger thanthem. Absorption spectra and fluorescence emission spectra of dyes were greatlyinfluenced by the solvents used. That is, peak locations are blue-shifted and thefluorescence emission intensity decreases with the increase of the solvent polarityparameter. It was also found that DPPB had a typical phenomenon that its fluorescencewas inclined to increase with the increasement of toluene content in the mixed solventcontainning toluene and acetonitrile.(3) DPPB and DHEASPBr-C4were used in the dyeing experiments on acrylicfabrics. The fluorescence emission spectra and CIE chromaticity coordinates showedthat the emission spectra of the fabric had blue shift over the spectra of the dye powder.The dyed fabric using DPPB showed blue green fluorescence, while dyed fabric usingDHEASPBr-C4showed yellow fluorescence. As shown in adsorption rates andbuilding-up properties, the adsorption rates of the dyes increased remarkably when thetemperature exceeded85℃. Although the equilibrium dye-uptake of DHEASPBr-C4was higher than that of DPPB, but the dyeing rate of DPPB was faster. Washing fastnessand rubbing fastness of dyed acrylic fabric were good, and the colour fastness of thedyed samples were all5grade.(4) The chromophoric group in DHEASPBr-C4structure was successfully graftedin P(AN-co-AA) copolymer chain and the nanofibre could be prepared throughelectrospinning process. The SEM results indicated that P(AN-co-AA) copolymer couldbe spun into fibers when it was simply blended with dyes or grafted with chromophoricgroups. Although the molecular structure was influenced for the grafting reaction, themacroscopic morphology of the copolymer fibers had little change. Meanwhile, the fiber uniformity had a slight change when the copolymer soultion was blended withdyes and it’s spinnability decreased. Fluorescence properties showed that the graftedcopolymer powder could produce yellow fluorescence.