稀土荧光高分子材料的制备与表征

【作者】 郭春芳；

【导师】 张明； 严长浩；

【作者基本信息】 扬州大学 ， 物理化学， 2007， 硕士

【摘要】 稀土高分子材料是通过稀土金属与高分子的复合而制备的一类兼具稀土光、电、磁等特性和高分子质轻、抗冲击和易加工等优良综合性能的功能材料。近年来,由于含发光稀土离子的高分子材料兼有稀土离子优异的发光性能和高分子化合物易加工的特点,引起了人们的广泛关注。稀土高分子发光材料的合成方法主要有:(1)稀土小分子配合物直接与高分子混合得到掺杂高分子发光材料;(2)高分子配体和小分子配体协同作用,通过共聚或均聚得到化学键合的高分子发光材料;(3)稀土配合物通过共价键嫁接于无机基质中,得到稀土高分子杂化发光材料。本文以氧化稀土为原料与α-甲基丙烯酸(MAA)直接反应得到具有聚合能力的稀土配合物单体,与邻菲罗啉(Phen)配合后,形成具有高荧光强度的稀土配合物。采用自由基溶液共聚得到化学键合的高分子光致发光材料。一、稀土有机配合物的合成与性能研究:本文以氧化稀土为原料直接合成了Eu-MAA-Phen单核配合物和Eu-La-MAA -Phen及Eu-Sm-MAA-Phen异核稀土配合物(heterometallic complexes)。采用元素分析、红外吸收光谱、紫外吸收光谱等对配合物的结构进行表征,结果表明配合物的组成均为RE(MAA)3Phen;同时还测试了配合物的热稳定性,对配合物进行X-衍射以及扫描电镜分析,表明配合物具有良好的晶形结构。对反应制得的一系列配合物的荧光测试表明,配合物在345～350nm均有强的吸收,都能发射Eu3+的特征荧光,最强荧光发射峰位在615nm附近,且Eu0.5La0.5- (MAA)3Phen配合物的荧光强度要大于Eu0.5Sm0.5 (MAA)3Phen配合物的荧光强度。同单核配合物的荧光强度相比,对于Eu0.5La0.5 (MAA)3Phen配合物,La的掺杂敏化了Eu3+的发光;而对于Eu0.5Sm0.5 (MAA)3Phen配合物,Sm3+的掺入却淬灭了Eu3+的发光。二、稀土共聚物的性能研究采用键合的方法将稀土离子引入到高分子材料基质中,选取苯乙烯和甲基丙烯酸甲酯两种单体,在引发剂的作用下进行聚合,合成了一系列具有发光性能的稀土键合型共聚物材料。本章共合成了Eu-Phen-co-PSt和Eu-co-PSt/Phen共聚物和Eu-Phen-co-PMMA和Eu-co-PMMA/Phen共聚物。首先研究了不同制备方法对聚合物结构和性能的影响,接着通过改变稀土配合物在聚合物中的含量,测试了不同稀土含量共聚物的荧光强度。对共聚物进行荧光测试表明:共聚物Eu-co-PS和Eu-co-PMMA均在200~400nm出现宽的吸收光谱,且在233nm附近的吸收最大,发射光谱图上均表现Eu3+的特征吸收峰,共出现472nm、592nm、615nm和700nm等发射峰位,加载550 nm的滤光片后,发射峰位移至564nm和606nm附近,且峰形变宽,但Eu-co-PSt/Phen较Eu-Phen-co-PMMA的荧光强度大。同时对不同稀土含量共聚物的荧光强度进行研究,发现随着配合物含量的增加,共聚物中稀土离子的含量逐渐增加,共聚物的荧光强度却呈现下降趋势,可能是由于稀土金属离子含量的增大,使的更多的配位结构单元及多重离子对聚集而成离子簇,使离子相对集中,金属离子间距离减小,故而导致荧光强度下降。本文的研究意义在于直接采用氧化稀土与羧酸类制备稀土络合物,研究其发光性能。通过聚合反应与苯乙烯和甲基丙烯酸甲酯合成稀土络合物共聚高分子,研究聚合反应和单体类型对稀土发光性能的影响,以期得到宽吸收高荧光强度的稀土荧光高分子材料。更多还原

【Abstract】 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.更多还原