稀土催化剂本体聚合异戊二烯的生胶性能

本体聚合与溶液聚合相比,具有能耗低,反应平稳,转化率高等特点。杨彩云等用稀土催化剂对异戊二烯(Ip)进行本体聚合,聚合转化率达80%以上,聚合物中无疑胶,且分子量分布较窄(M_w/M?<2)。本文报道和讨论本体聚合放大试验胶样的生胶特性。 异戊二烯胶样(BLn-IR)本所自制。溶液钛催化聚异戊二烯IR-1Q为日本JSR生产。天然橡胶(NR)系海南岛3~#烟片。门尼粘度按GB1232测定。应力-应变性能(23℃),用DL-1000B型电子拉力机测定,拉速500mm/min。玻璃化温度(T_g)用PE DSC-2C型仪测定,升温速率     

Thermal decomposition of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with rare-earth elements in air atmosphere

The present work provides data concerning thermal decomposition of 2,2′-dipyridyl(2-dipy) and 4,4′-dipyridyl(4-dipy) with rare-earth elements (Ln) based on literature and our own sustained studies which comprised about 100 complexes.

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Zusammenfassung Ausgehend von Literaturangaben und unseren eigenen Untersuchungen von mehr als 100 Komplexen liefert vorliegende Arbeit Angaben zur thermischen Zersetzung von 2,2′-Dipyridyl(2-dipy) und 4,4′-Dipyridyl(4-dipy) mit Seltenerdenelementen (Ln).

     

Crystal structure of the La3+ sandwich complex based on 8-membered macrocyclic siloxanolate ligands

The product of the reaction between anhydrous lanthanum trichloride and potassium vinylsiloxanolate, K₅[VinSiO₂]₈La₄(₄-OH)[O₂SiVin]₈ · 5n-BuOH·2H₂O has been studied by X-ray diffraction. The compound is a «sandwich»-type complex where macrocyclic vinyloctasiloxanolate ligands with regularcis-configuration have co-axial and antiparallel orientation. These ligands coordinate a planar «cationic layer» formed by four La³⁺ ions and stabilized by an additional ₄-OH^– bridge ligand. A three-dimensional cage structure of complex lanthansiloxanolate pentaanions linked through the coordinated K⁺ counter-ions is formed in the crystal studied.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 184–189, January, 1993.     

Studies on the synthesis and thermal decomposition mechanisms of rare-earth metal (Pr,Nd, Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one

Three new rare-earth metal (Pr, Nd and Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one (NTO) were prepared and characterized. The thermal behaviour of the three salt hydrates, M(NTO)₃·nH₂O (M=Pr and Nd,n=9;M=Sm,n=8) were studied by means of TG and DSC under conditions of linear temperature increase. The thermal decomposition intermediates were determined by means of IR, MS and X-ray diffraction spectrometry. The thermal decomposition mechanisms of these hydrates were proposed as follows: We express our thanks to Professor Zhu Chunhua, Associate Professor Fu Xiayun, and Lecturers Fan Tao and Liang Yanjun for their help in this work.     

微波溶样－ICP－AES法测定人发标准物质中15种超痕量稀土元素的研究

本文采用微波溶样，不经分离富集，直接用标准加入ＩＣＰ－ＭＳ法，测定人发标准物质中１５种超痕量稀土元素。选择了最佳样品预处理条件和测定的最佳仪器参数。检出限为０．００７～０．０２６ｎｇ／ｍＬ。用国家一级土壤标准物质（ＧＢＷ０７４０１和ＧＢＷ０７４０３）作为质控样，１５种痕量稀土元素的测得值与标准值很好地吻合，相对标准偏差（ＲＳＤ）为１．２％～５．４％。国家一级人发标准物质（ＧＢＷ０７６０１）中稀土元素的标准值仅有Ｌａ，Ｃｅ和Ｙ，本法测得值均落在标准值的置信区间内。其余１２个超痕量稀土元素本法也取得了较为满意的结果。     

Hexadecapropyloxy-substituted diphthalocyanine complexes of rare-earth elements: synthesis,spectroscopic and electrochemical studies

Hexadecapropyloxy-substituted diphthalocyanine complexes of rare-earth elements (REE = Lu, Tm, Sm) were synthesized. The new symmetrically substituted diphthalocyanine complexes prepared starting from 4,5-dipropyloxyphthalodinitrile (phthalogen) are characterized by better solubilities compared to the known hexadecamethyl-substituted diphthalocyanine complexes of the same REE. Spectral and electrochemical characteristics of the complexes were studied. The compounds can be used as materials for high-contrast electrochromic devices.     

Electronic Structure of TiSe2 and TiSe2 Intercalated with Eu

Abstract

We report on a PE study of the electronic structure of pristine TiSe₂. The experimental data are compared with results of band-structure calculations. It is confirmed that TiSe₂ reveals semimetallic properties. For the first time rare-earth metals were attempted to be incorporated in situ into TiSe₂. It is found that divalent Eu can be easy intercalated, whereas deposition of trivalent Gd leads to strong interfacial reactions. The electronic structure of the Eu-intercalation compound cannot be simply described within a rigid-band approach assuming charge transfer from Eu to unoccupied Ti d states. In a more elaborated approach hybridization phenomena have to be taken into consideration.     

Effect of rare earth elements on the structural and optical properties of PMMA for possible uses in polymer optical communications

Rare-earth elements (REEs) as Tm⁺³, Er⁺³, Yb⁺³ and Nd⁺³ have a significant optical photon emission. Therefore, Films of PMMA doped with 5?wt.% of NdCl₃, TmCl₃, ErCl₃ or YbCl₃ were prepared using the casting technique. FTIR of the prepared films has been studied. The optical and dispersion behavior of all doped samples have been investigated. The reflectance (R) and the transmittance (T) were measured in the wavelength range of 200–2500?nm. FTIR of all PMMA reveals that, REEs addition to PMMA samples creates new transmission peaks C=O groups and a decrease in the intensity of the absorption band of C–O groups has been obtained. The results showed the dependency of the refractive index and energy gap on the REE electronic transitions nature. The obtained results suggest strongly the applicability of these PMMA derivatives in improving the performance of the polymer optical fiber (POF).     

稀土铕-芳香羧酸-邻菲罗啉三元有机配合物的合成、表征及发光性能

分别以4种芳香羧酸—对甲基苯甲酸(PMBA)、对氯苯甲酸(PCBA)、对溴苯甲酸(PBr BA)、对氨基苯甲酸(PABA)—作为第一配体,邻菲罗啉(phen)为第二配体,采用溶剂热法合成了4种稀土铕离子(Eu3+)的三元有机配合物。通过元素分析、红外光谱、热重分析等手段确定配合物的化学结构,结果表明,4种配合物的组成可表示为Eu L3phen·H2O(L=PMBA、PCBA、PBr BA、PABA),芳香羧酸配体和邻菲罗啉均与稀土Eu3+配位;铕配合物在318℃以上才开始出现明显失重,表明其具有良好的热稳定性。研究了4种芳香羧酸配体对紫外光的吸收性能。通过荧光光谱研究了配合物的发光性能,4种配合物均发出Eu3+的特征荧光,5D0→7F2电偶极跃迁发射峰强度顺序为:Eu(PBr BA)3phen·H2OEu(PMBA)3phen·H2OEu(PCBA)3phen·H2OEu(PABA)3phen·H2O;其国际照明委员会(CIE)色坐标均落在红光区域,能发出纯正的红光。     

Easy and General Synthesis of Large‐Sized Mesoporous Rare‐Earth Oxide Thin Films by ′Micelle Assembly′

Large‐sized (ca. 40 nm) mesoporous Er₂O₃ thin films are synthesized by using a triblock copolymer poly(styrene‐b‐2‐vinyl pyridine‐b‐ethylene oxide) (PS‐b‐P2VP‐b‐PEO) as a pore directing agent. Each block makes different contributions and the molar ratio of PVP/Er³⁺ is crucial to guide the resultant mesoporous structure. An easy and general method is proposed and used to prepare a series of mesoporous rare‐earth oxide (Sm₂O₃, Dy₂O₃, Tb₂O₃, Ho₂O₃, Yb₂O₃, and Lu₂O₃) thin films with potential uses in electronics and optical devices.