The WCl6-e-Al-CH2Cl2 catalyzed polypentenamer formation via ring-opening metathesis polymerization (ROMP)

The synthesis of polypentenamer by an electrochemically generated metathesis polymerization catalyst from methylene chloride solution of WCl₆ was investigated. The active species formed by electroreduction of this salt under controlled potential of +900 mV at a platinum cathode with an aluminum anode were found to catalyze the ring-opening metathesis polymerization (ROMP) of cyclopentene, monocyclic olefin of relatively low strain, in high yield (89%) and at short period (32 min) under mild conditions. The effect of reaction parameters, e.g., olefin/catalyst ratio, reaction time, electrolysis time, catalyst aging, on the polymerization yield have been studied. The resulting polymer has been characterized by ¹H and ¹³C NMR, IR and gel permeation chromatography (GPC) techniques. Analysis of the polypentenamer microstructure by means of ¹³C NMR spectroscopy indicates that the polymer contains a mainly trans stereoconfiguration of the double bonds (σ_c = 0.31) and a slightly blocky distribution (r_tr_c > 1) of cis and trans double bond dyads (r_tr_c = 1.44). However, this electrochemical system is reluctant to facilitate the competing vinyl type addition polymerization reactions.     

AROMATIC AND HETEROCYCLIC NITRILES AND THEIR POLYMERS ⅩⅧ. THE POLYMERIZATION KINETICS OF BENZONITRILE CATALYZED BY METAL ACETYLACETONATE

The bulk polymerization of benzonitrile catalyzed by Co(Ⅱ), Co(Ⅲ) and Fe(Ⅲ) acetylacetonate was studied. The results of kinetics study show that the rate of polymerization was proportional to first power of the concentration of catalyst and second power of the concentration of monomer.     

Novel preparation of organic polymer-based monolithic column by microwave irradation

Microwave irradiation was firstly attempted for the preparation of organic-based monoliths of poly（styrene-divinylbenzene- methacrylic acid）, which single step in situ polymerization was carried out during 15 min. The colunm permeability, electrophoretic and chromatographac behaviors were comparatively evaluated using pressure-assisted CEC, GEC and low pressure-driven separation modes. The largest theoretical plates for the preparing column could be close to 18,0000 plates/m for thiourea in the mode of p-CEC. It provided a viable alternative to traditional initiation means for the perparation of monolithic capillary columns.     

VOCl_3/Et_3Al_2Cl_3/CCl_4溶剂体系催化乙烯丙烯共聚

本文以VOCl_3/Et_3Al_2Cl_3为催化剂,在CCl_4溶剂中进行乙烯共聚反应。在聚合过程中,发生一异常的颜色突变现象。颜色突变后,体系催化聚合生成分子量很低的产物。从聚合物的结构表征及机理探讨表明:颜色突变后,体系产生了新的活性中心,催化机理发生了转变——由配位机理转变为阳离子机理。     

N-(p-乙烯氧基苯基)咔唑的合成和聚合

本文是含咔唑化合物及其聚合物系列研究的一部分,以对-溴苯酚为原料,经过乙烯基醚化,再同咔唑反应、合成了新的单体,N-(p-乙烯氧基苯基)咔唑(NEOPC),经过元素分析、NMR和IR等对NEOPC进行分析鉴定,研究了它的聚合行为。     

丙烯腈水相沉淀聚合研究进展

结合近几年的研究成果,笔者对丙烯腈水相沉淀聚合机理、聚合动力学、动力学数学模型诸方面问题进行了系统的综述,反映了该领域的研究概况和最新研究成果.     

Synthesis, crystal structure of bis(arylamido)lanthanide methyl complexes and their catalytic behavior for the polymerization of methyl methacrylate

Reactions of [N(C₆H₃i-Pr₂-2,6)(SiMe₃)]₂LnCl(THF) (Ln=Nd, Yb) with two equivalents of MeLi in a mixture solution of toluene and Et₂O gave [N(C₆H₃i-Pr₂-2,6)(SiMe₃)]₂LnCH₃(μ-CH₃)Li(THF)₃·PhCH₃ (Ln=Nd (1), Yb (2)) in good isolated yields as crystalline solids. The single-crystal structural analysis of 2 revealed that the coordination geometry of ytterbium ion is best described as a distorted pseudo-tetrahedron. Both 1 and 2 are active for the polymerization of methyl methacrylate to give syndiotactic-rich and high molecular weight polymers (M_n>10⁴) with relatively narrow molecular weight distributions (M_w/M_n<2).     

碳五馏分中微量阻聚剂二乙基羟胺的气相色谱测定法

提出采用HP-l毛细管色谱柱测定碳五馏分中微量阻聚剂二乙基羟胺组分的气相色谱方法。在本文提出的条件下，二乙基羟胺与其他组分分离良好，检出限低于20mg／kg，相对标准偏差为3．86％，结果准确可靠，方法满足控制分析的要求。     

直接酯化法合成PET反应条件对树脂结晶速率的影响

用直接酯化法合成了聚对苯二甲酸乙二酯（ＰＥＴ）。对缩聚反应温度、真空度及稳定剂等合条件对产物结晶速率的影响进行了研究。以ΔＴｃ＝Ｔｃ－Ｔｇ和ΔＴｃｏ＝Ｔｃｏ－Ｔｇ表征样品的结晶速率。结果表明，真空度一定，反应温度高则样品结晶速率慢；温度一定，真空度高样品结晶速率也慢。这两个因素的影响均是不可忽视的。     

Physical properties and electrochemical performance of LiMn2O4 cathode materials prepared by a precipitation method

LiMn₂O₄ powder for lithium-ion batteries was prepared by a precipitation method, and the effects of calcination temperature on the physical properties and electrochemical performance of the samples were investigated by various methods. The results of X-ray diffraction (XRD) showed that the lattice parameter (a) and the unit cell volume (v) decrease with the increasing calcination temperature, and the LiMn₂O₄ sample calcined at 750°C has smaller particle size and higher crystallinity than other samples. The results of the electrochemical experiments showed that the sample calcined at 750°C has larger peak currents, higher initial capacity, and better cycling capability, because of its lower charge-transfer resistance and larger diffusion coefficient of Li⁺ ions than those of other samples.