Study On Synthesis And Properties Of Rare Earth Complex And Its Application In Polymer Materials

Rare earth elements are characteristic of luminescent, electric and magnetic properties due to their particular electron structure. When the rare earth ions react with the organic ligands, the luminescent properties would be more intensied since the molecular energy in the ligands transfers to the central ions of the rare earth complex. The rare earth aromatic carboxylic acid compound is a kind of good luminescent material and will have great application in such fields as luminescence, display, electron photo carve and solar energy transference. Synthetic polymer possesses such advantages as rich raw materials resources, convenient synthesis, easy processing, strong pound-resistance, light weight and low cost. If connecting both advantages to synthesize rare earth polymer complexes, it is possible to develop new rare earth functional materials.A series of novel Eu³⁺ rare earth complexes, composed of 4-hydroxybenzolate acid and 1,10-phenanthroline ligands at various reactant mole ratio as well as different pH values of the reaction solution were synthesized under anhydrous ethanol. The apparent morphology, composition, thermal stability and fluorescent property of the rare earth complex were measured by TEM Element analysis IR TG and Fluorescence spectrometer. The resolvable ability and the fluorescence characteristic were also tested. The results indicated that the optimal pH value of the reactive solution was 7 and the reactant mole ratio was 1:3:1, also this rare earth complex had the most excellent crystalline structure and its structure formula was: Eu（HOC₆H₄COO）₃（phen）H₂O. Fluorescence spectra showed that the rare earth complex could be well excited in a relatively broad wavelength range and exhibited excellent luminescent performance with the characteristic emission peak of Eu³⁺ ions. The TEM results indicated that this rare earth complex had sphere-like morphology and its diameter was about 100 nm. This showed that the organic rare earth complex was nanoparticle and will be useful for preparation of high transparent light-ecological agriculture film and luminescence fiber with excellent fluorescent quality.The blend experiments were designed with the different proportion as-prepared organic rare earth complex and polyethylene. The results demonstrated that the low content of the complex （< 5%） had no remarkable effect on the melting point of the polyethylene, which showed the hybrid polymer could satisfy the processing technology requirement of film-forming. The SEM photos displayed the complex dispersed uniformly in the polymer base. No condensed conglobation phenomenon would be found even the content of the rare earth complex reached to 5% and the size of the sample was 100-200 nm. The fluorescence spectra of the blended samples had the similar Eu³⁺ characteristics peak whose intensity was enhanced along with the increasing content of the complex.In the following experiments, the series of luminescent fibers were produced with the rare earth complex and the polypropylene resin by the melt blending method. The IR spectra of the luminescent fibers （wt.2.5%） showed that the complex could dope well in the resin and its structure has no change in the blending process. The fluorescence test manifested that the fibers had Eu³⁺ characteristic peak which the peak position was 618 nm and the relative luminescent intensity was 698. Furthermore, the content of the complex influenced the fluorescence property of the fiber. The intensity had an obvious improvement with the increasing of content complex while the intensity would reduce when the content reached to a high value （5%）.The experiments results showed that the fluorescent quenching phenomena did not happen when the rare earth complex had been added to polyethylene, which could be produced a type of light conversion agriculture film. The luminescent fiber was prepared by blending melt-spinning with rare earth complex and polypropylene resin at different weight ratio. It also has a good luminescent quality and could be considered suitable for industrial application such as falsification-preventing and decorations for textile and clothing.