Preparation And Characterization Of Rare Earth Fluorescent Polymer Materials

Rare earth polymer materials, cooperated by rare earth ions and polymer matrix, possessing the distinctively optical, electrical and magnetic properties of RE ions, are a new type of functional materials. Recent years, these materials have attracted much attention due to their excellent luminescence properties and good machinability. There are several synthesis methods: (1) organic rare earth complex was doped into polymer to form rare earth-doped polymer; (2) the combinatorial luminescence of rare earth polymer complex were synthesized. Using macromolecule ligand and organic ligand cooperation effect, the rare earth polymer photo-luminescent was obtained by copolymerizing or polymerizing; (3) by doping of rare earth complex into inorganic matrix material, luminescence rare earth polymer hybrid materials were synthesized.The polymeric rare earth complex monomer was synthesized by RE oxide and methacrylic acid (MAA) .It was cooperated with 1, 10-phenanthroline (Phen) and the good fluorescent rare earth complex was prepared. Combinational luminescence rare earth polymer materials were synthesized by free radical copolymerization of monomer with RE-methacrylate comp- lexes in solution. Compared with the blending system, binding the rare earth complexes directly to the polymer chain, would result in the enhancement of photoluminescence.1. Synthesis and properties study on rare earth organic complexesThe Eu-MAA-Phen mononuclear rare earth complex and Eu-La-MAA -Phen and Eu-Sm-MAA-Phen binuclear rare earth complexes were prepared. The complexes structure and properties were characterized by elemental analysis, FT-IR and UV-Vis. The thermal stability properties of complexes were testified by the thermal analysis. X-ray powder diffraction and SEM analysis study of the synthesized lanthanide compounds indicates that they have good crystalline form.Fluorescence measurements of series of rare earth complexes were carried out at 615 nm, while showing strong absorption excitation in the 345~ 350 nm range. They all can emit the intrinsic fluorescence of Eu3+.The fluorescence intensity of Eu0.5La0.5- (MAA)3Phen complex was higher than the intensity of Eu0.5Sm0.5 (MAA)3Phen complex. Compared to the mononuclear rare earth complex, the enhancement of the fluorescence intensity of Eu0.5La0.5 (MAA) 3Phen binuclear complex due to the sensitization of La3+, while the decrease of the fluorescence intensity of Eu0.5Sm0.5 (MAA) 3Phen was attributed to doping with Sm3+.2. Synthesis and properties study on rare earth copolymersThe rare earth ions were doped into the polymer matrix using the combinatorial method. A series of high luminescence copolymer was synthesized by polymerizing methyl methacrylate (MMA) and Styrene (St) with europium-methacrlate complex in solution with AIBN as initiator, respectively. Eu-Phen-co-PSt and Eu-co-PSt/Phen copolymer,Eu-Phen-co-PMMA and Eu-co-PMMA/Phen copolymer were synthesized. Polymerization methods and the properties of copolymers were studied. The Fluorescence intensity of copolymers was investigated with different content of rare earth complex in the system.Fluorescence measurements manifest the excitation spectra of europium- methacrlate complex in PMMA and in PSt are similar, and show a broad band between 200 nm to 400 nm, with the maximum wavelength near 233nm. The emission transitions centered near 472nm,592nm,615nm and 700nm. Loading 550nm filter, with the increasing of peak width, the emission peaks shift to 564nm and 606nm. The fluorescence intensity of Eu-co-PSt/Phen is higher than that of Eu-co-PSt/Phen copolymer.The fluorescence intensity of copolymers was tested with different concentration of Eu3+ in the system. The luminescence intensity of copolymers decrease with an increase in the europium-methacrlate complex content in the PMMA and PSt matrix. It may result from the structural units and multiple ion couples gather to ionic cluster, which was made the ions relatively concentrate and decreased the distance among ions.The purpose of those studies is to synthesize the rare earth complex by the method with rare earth oxides and carboxylic acid directly. The high fluorescence transparent rare earth copolymers were prepared by copolymerizing MMA and St with europium-methacrlate complex. The influence on the luminescence properties of rare earth was studied in polymerization conditions and the types of monomer. The finally aim is to obtain broad absorbing spectra and high fluorescent of rare earth polymer materials.