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RE / polymer composites and their submicroscopic structure and luminescence , radiation shielding and magnetic Relations

Author: LiuLi
Tutor: JinRiGuang
School: Beijing University of Chemical Technology
Course: Materials Science
Keywords: Fluorescence JRG sub-cluster theory Magnetic Polymer Radiation Protection Rare earths
CLC: TB332
Type: PhD thesis
Year: 2004
Downloads: 760
Quote: 5
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Abstract

In this thesis, the use of physical and chemical properties of rare earths from the optical properties, radiation shielding and magnetic properties of these three aspects, preparation of a variety of different properties of organic lanthanide complexes and prepare a variety of different uses of inorganic and organic rare earth / polymer composites, a more systematic study of the specificity of these materials can and composite relationships between structure and properties. Also, use the fourth statistical theory-JRG sub-cluster theory to the material properties are described theoretically. The light-emitting properties, the main results are: (1) Synthesis of a reactive and a high luminescent Re (tta) 2 (aa) phen complex, high luminescent Re (tta) 3phen complexes, and a reactive The Sm (aa) 3 complexes. Re (tta) 2 (aa) phen and Re (tta) 3phen all have high fluorescence intensity, and the average fluorescence emission characteristic RE3 ion peaks. (2) The experiments were performed in the lanthanide complexes combined with rubber luminescent materials prepared a new attempt, using the easy and rare earth ions coordinated NBR rubber and has excellent chemical stability SiR with high luminescent Re (tta) 3phen (RE = Eu, Sm) complexes prepared composite has excellent fluorescence properties of rare earth / polymer composites. (3) This is the first proposed the use of in-situ reaction method RE / polymer composite luminescent material, and for the first time prepared by in situ reaction with excellent mechanical properties of Sm (aa) 3/NBR performance composite materials and fluorescent The Re (tta) 2 (aa) phen / NBR composite materials, particularly Re (tta) 2 (aa) phen / NBR vulcanized rubber composite mix fluorescence intensity ratio of fluorescence intensity increase exponentially. By SEM, TEM observation of morphology of materials, it can be seen, in-situ reaction of the composite material prepared, the rare earth sulfide dispersed phase particle size and the number of changes significantly before and achieve good dispersion, verified by in situ the reaction can be prepared with high rare earth content, and high fluorescence intensity uniform dispersion of rare earth / polymer composite of this fact. Ray shielding performance in research, the main results are: (a) by filling plus the four different kinds of inorganic atomic number of rare earth [lanthanum carbonate (LaCO3), praseodymium carbonate (PrCO3), samarium oxide (Sm2O3), gadolinium oxide (Gd2O3)] to rubber, to prepare a radiation shielding composites, we found that the radiation performance of the composite material filled with the amount of rare earth elements added increases, and a rare earth element with atomic number of filled plus the increase . (2) in a peroxide cure system as, by extending the curing time can be reduced Gd (aa) 3 in the rubber matrix dispersed particle size, to increase the uniformity of the dispersion, thereby improving the material and the P-value tensile strength. When the curing system using the same, the use of NR as a matrix rubber of the rubber specimen radiation performance than an NBR rubber as the base of the sample, i.e. the choice of the base gum radiation properties of the material, there are certain effects. (3) of the metal content is small (ie, a small amount of rare earth elements), the use of gadolinium oxide, acrylic acid as a filler than the radiation of gadolinium as a filler better performance. However, the increase of the metal content, the use of acrylic acid gadolinium as a filler system rather than using the P-value of gadolinium oxide filler system as a P value is large. In the magnetic properties, the main results are: (1) at room temperature (300K) under, Gd (ba) 3 is a paramagnetic material, which is low to render the strong magnetic metal Gd vary. (2) Nd (aa) 3 at room temperature (300K) was also significantly lower paramagnetic. (3) lt; WP = 3 gt; magnetic moments of the rare earth complexes with rare earth ion magnetic moment measured relatively consistent, indicating that their magnetic properties from rare earth ions themselves, but with the ligand coordination environment provided little . (4) Nd (aa) 3/PU composite materials at room temperature, paramagnetic substances in the 5-300K temperature range, the composite material is lower than the saturation magnetization g of Nd (aa) 3 performance, explanatory material Nd3 itself depends on the magnetic properties, and its content is related. In Eu (tta) 2 (aa) phen / NBR composites luminous intensity and sub-cluster theory studies the relationship between the scale, the main results are: (a) after curing later, R1 and R2 values ??are reduced, indicating that the system of large and small particle size are reduced to different extents. Vulcanizates greatly reduced value R1 · R2, close to 0, indicating that the system earth particle dispersion uniformity increases beneficial Earth in situ reaction of the dispersion matrix. After vulcanization, R2/R1 value is increased, while the system luminous intensity, indicating that R2 / R1 and the fluorescence intensity has a direct relationship, i.e. the finer particles of greater luminous intensity. (2) vulcanized rubber R1 · R2 becomes small, indicating that the effect of the in situ reaction, the reaction heat is effectively converted earth are dispersed activation energy required to enable the system to achieve a higher overall activation energy, meet high highest energy principle uniformly dispersed. Visible, vulcanized rubber mix more easily than the excitation energy to outside, thus vulcanized rubber and the luminous intensity of the light emission efficiency is higher than the rubber compound. In Sm (tta) 2 (aa) phen / NBR composites luminous intensity and sub-cluster theory studies the relationship between the scale, the main results are: (1) vulcanizates R1 and R2 values ??are close, indicating that the system is large, there is a tendency to have a small particle becomes small, which is a large particle size is decreased, a small increase in the size of particles, the particle size distribution to form the focus of the case. Vulcanizates R1 · R2 values ??decrease, close to 0, indicating that the system earth particle dispersion uniformity increases beneficial Earth in situ reaction of the dispersion matrix. Vulcanized rubber compound R2/R1 value is greater than the high, indicating the system of organic complexes of rare earth monomers from the oligomers formed are continuously precipitated from the matrix and the aggregation tendency, of course, this aggregate particle size is still far Smaller mix particle size dispersed in earth. This change is in fact to improve the uniformity of the dispersion. (2) R1 · R2 vulcanizate becomes smaller, indicating that the effect of the in situ reaction, the reaction heat is effectively converted particle dispersion of rare earth activation energy required to reach a higher activation energy of the system overall, meet high highest energy principle uniformly dispersed. Visible, vulcanized rubber mix more easily than the excitation energy to outside, thus vulcanized rubber and the luminous intensity of the light emission efficiency is higher than the rubber compound. In the Gd (aa) 3/NR composite shielding performance (P and M values) and the sub-cluster theory studies the relationship between the scale, the main results are: (1) With the curing progresses, R1 and R2 values ??are changing , which shows that the system there is a \Here the word \As the curing progresses, these \

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