对苯二腈氧化物的合成及其室温固化性能

以对苯二甲醛为原料,聚丁二烯(LPB)为基体,将合成的对苯二氯代醛肟和三乙胺反应,制备出高活性的固化剂对苯二腈氧化物,将其与LPB反应制备出室温固化的弹性体。探究了对苯二氯代醛肟的最佳用量,采用FTIR对弹性体进行了结构表征,利用TG、DSC、接触角和FSEM对弹性体表面性能进行了考察,对弹性体的拉伸强度、断裂伸长率和邵氏硬度进行了测试。结果表明:弹性体在8%~12%(对苯二氯代醛肟质量占LPB质量的百分数,下同)固化比例下,随着对苯二氯代醛肟用量的增加,弹性体的拉伸强度从0.21 MPa增加到0.45 MPa,断裂伸长率从83%减小到51%,模量从0.26 kPa增加到0.88 kPa,玻璃化转变温度(Tg)从-82.28℃降到-83.76℃。对苯二氯代醛肟用量为10%时,制备的弹性体的拉伸强度为0.35 MPa,断裂伸长率为53%,模量为0.66 kPa,邵氏硬度为34.6 Ha,T5%和T10%(弹性体失重5%和10%时所对应的温度)分别为234.85℃和330.46℃,弹性体与水的接触角达到112.11°。室温固化大大提高了弹性体的热稳定性和力学性能。     

CdS纳米粒子的室温固相反应制备及其光催化活性研究

以牛血清白蛋白为稳定剂,采用CdSO4.8H2O、硫脲和NaOH之间的室温固相反应制备了高分散立方晶相粒径为4~5 nm的CdS纳米颗粒。用X射线洐射(XRD)、透射电镜(TEM)和原子力显微镜(AFM)对CdS纳米颗粒的相组成,形貌和粒径等进行了表征。以甲基橙降解脱色为探针反应,研究了自然光照条件下,CdS纳米颗粒的光催化活性,即光催化剂用量,试液的pH值,光照及时间等与甲基橙脱色率的关系。在最佳光催化剂用量为0.2 g,最佳pH值为1时,太阳光照射1 min,甲基橙降解率可达99%以上,表明由室温固相反应制备的CdS纳米颗粒,具有优异的光催化活性。     

Biological Properties of Iron Oxide Nanoparticles for Cellular and Molecular Magnetic Resonance Imaging

Superparamagnetic iron-oxide particles (SPIO) are used in different ways as contrast agents for magnetic resonance imaging (MRI): Particles with high nonspecific uptake are required for unspecific labeling of phagocytic cells whereas those that target specific molecules need to have very low unspecific cellular uptake. We compared iron-oxide particles with different core materials (magnetite, maghemite), different coatings (none, dextran, carboxydextran, polystyrene) and different hydrodynamic diameters (20–850 nm) for internalization kinetics, release of internalized particles, toxicity, localization of particles and ability to generate contrast in MRI. Particle uptake was investigated with U118 glioma cells und human umbilical vein endothelial cells (HUVEC), which exhibit different phagocytic properties. In both cell types, the contrast agents Resovist, B102, non-coated Fe₃O₄ particles and microspheres were better internalized than dextran-coated Nanomag particles. SPIO uptake into the cells increased with particle/iron concentrations. Maximum intracellular accumulation of iron particles was observed between 24 h to 36 h of exposure. Most particles were retained in the cells for at least two weeks, were deeply internalized, and only few remained adsorbed at the cell surface. Internalized particles clustered in the cytosol of the cells. Furthermore, all particles showed a low toxicity. By MRI, monolayers consisting of 5000 Resovist-labeled cells could easily be visualized. Thus, for unspecific cell labeling, Resovist and microspheres show the highest potential, whereas Nanomag particles are promising contrast agents for target-specific labeling.     

Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies

Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.     

Effect of Cobalt and Nickel Doping on Structural and Magnetic Properties of Iron Oxide Nanoparticles

Two series samples of Iron Oxide nanoparticles doped with nickel and cobalt with different doping values (x?=?0.01; 0.03; 0.05 and 0.07), were successfully synthesized by using sol–gel method, and then they were characterized by X-ray diffraction, scanning electron and vibrating sample magnetometer (VSM). X-ray diffraction analysis of two series samples showed the formation α-Fe₂O₃ nanoparticles, accompanied by two phases iron spinels, CoFe₂O₄ and NiFe₂O₄. In addition, the variations in grain size were observed for both two series. The observation by scanning electron microscopy reveals a change in the morphology of the grains of all the samples doped, which confirm the cobalt and nickel effect on the morphology of iron oxide nanoparticles. Magnetic measurements which were measured by VSM showed significant magnetic parameters such as coercivity and magnetization besides the ferromagnetic behavior of both two series doped with Cobalt and Nickel.

     

Studying the Effect of Cobalt Doping on Optical and Magnetic Properties of Zinc Oxide Nanoparticles

Silicon - Nano-crystalline powders of Zn1−xCoxO with $left (0.0le xle 0.07 right )$ have been synthesized by sol-gel method. X-ray diffraction patterns of the prepared samples confirm the...     

Size-Controlled Synthesis of Colloidal Gold Nanoparticles at Room Temperature Under the Influence of Glow Discharge

Highly dispersed colloidal gold (Au) nanoparticles were synthesized at room temperature using glow discharge plasma within only 5 min. The prepared Au colloids were characterized with UV–visible absorption spectra (UV–vis), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) equipped with an energy dispersion X-ray spectrometer (EDX). UV–vis, XPS and EDX results confirmed that Au³⁺ ions in HAuCl₄ solution could be effectively reduced into the metallic state at room temperature with the glow discharge plasma. TEM images showed that Au nanoparticles were highly dispersed. The size of colloidal Au nanoparticles could be easily tuned in the nanometer range by adjusting the initial concentration of HAuCl₄ solution. Moreover, the as-synthesized Au colloids (d _av = 3.64 nm) exhibited good catalytic activity for glucose oxidation. The nucleation and growth of colloidal Au particles under the influence of the plasma was closely related with the high-energy electrons generated by glow discharge plasma.     

固相反应制备纳米氧化锡

用室温固相化学反应法制备了氧化锡纳米晶体。在室温下让含一定量表面活性R的碳酸氢铵粉末与五水氯化银粉末按一定的摩尔比混合研磨，得到含有氧化锡前驱体以及可溶性无机盐的混合物。用水洗去混合物中的可溶性无机盐并干燥后，得到纯的前驱体。前驱体经高温热裂解得到氧化锡纳米晶体。经xRD表征，可知氧化锡为4．2nm左右的纳米晶体。     

纳米氧化锌的室温合成及表征

文章以醋酸锌、氯化锌和氢氧化钠为原料,在室温下成功制备了氧化锌纳米晶。制备的氧化锌样品用x射线衍射仪、透射电镜、荧光光谱仪等进行表征。XRD结果表明,制备的氧化锌样品为六方纤锌矿结构且具有好的结晶度;从透射电镜照片可以看出,氧化锌颗粒分散性较好,平均粒径在6～10nm;从紫外吸收光谱可以看到,在200-380nm具有很强的紫外吸收,在400-800／lm的可见光区吸收则比较弱;在340nm的激发光下,氧化锌呈现出较好的蓝光和绿光发光效应。     

对苯二腈氧化物的合成及其对聚丁二烯室温固化性能的研究

以聚丁二烯液体橡胶（LPB）作为粘合剂,加入合成的1,4-对苯二氯代醛肟及三乙胺后进行1,3-偶极环加成反应,实现对聚丁二烯的室温(25℃)固化,以寻找最佳的固化比例。使用FTIR、核磁、质谱、对化合物进行结构表征;用FTIR对弹性体进行结构研究;拉伸强度和断裂伸长率、邵氏硬度对弹性体进行力学性能研究;TG、DSC、接触角和FSEM对弹性体表面性能进行研究。结果表明：合成的氯代-对苯二甲醛肟产率为94%,加入三乙胺后在室温下能实现对聚丁二烯的固化;固化剂含量为10%时,制备的弹性体的拉伸强度为0.35MPa,断裂伸长率为53%,模量为0.66KPa力学性能优异;固化剂含量10%弹性体的接触角为112.76?,达到最大值,弹性体疏水性能最好。室温固化弥补了传统固化技术中的不足,大大提高了弹性体的耐热性和力学性能。     

常温合成3,4-二甲基二亚苄基山梨醇

以D-山梨醇和3,4-二甲基苯甲醛为原料,乙醇为反应介质,在对甲苯磺酸催化下常温合成了3,4-二甲基二亚苄基山梨醇。通过正交实验确定最佳的实验条件为:D-山梨醇与3,4-二甲基苯甲醛摩尔比为1∶1.75;对甲苯磺酸与3,4-二甲基苯甲醛摩尔比为0.7∶1,乙醇为溶剂;反应时间为6h;产率71.0%,熔点270~272°C。经红外光谱对该产品进行了表征。     

超声波辅助室温下合成介孔材料MCM-48

在室温碱性介质中,以不同功率的20 kHz超声波辅助合成了MCM-48介孔材料,考察了超声波功率、作用时间、反应物料配比及体系pH值对产品有序度的影响,并对介孔材料进行了XRD、低温N2吸附、SEM和TEM表征.结果显示,在相同反应时间内,经超声波辅助可以得到比普通室温合成法具有更大孔径、更高有序度的MCM-48.得到优化的合成条件为:功率460 w、反应时间1.5 h、无水乙醇与水的摩尔比为0.5、体系的pH值11.7、CTAB和TEOS的浓度分别为0.11～0.12 mol·L-1和0.27～0.31 mok·L-1.     

Rapid Synthesis of DDR Zeolite at Room Temperature

In this work, DDR zeolites were synthesized by sonochemical method without the application of any heat energy at room temperature. The synthesized zeolites were characterized by X‐ray diffraction (XRD), infrared (IR) spectral analysis, and field‐emission scanning electron microscopy (FESEM). XRD and IR results showed that phase pure DDR zeolite was started to form at room temperature after 24 h of aging and completed the formation after 5 d of aging. The Brunauer–Emmett–Teller (BET) surface area of the powder was found to be 202 m²/g. The FESEM micrograph and elemental analysis showed that desired atomic ratio of the DDR zeolite was obtained after 5 days of synthesis.     

钴钕软磁性复合氧化物的溶胶-凝胶法合成及表征

以Co(NO3)2.6H2O和Nd(NO3)3.6H2O、PVA等为原料,采用溶胶-凝胶法制备出前驱体,将其高温煅烧获得钴钕复合氧化物粉体。通过TG-DSC、FT IR、Raman、TEM、XRD、PPMS等检测对前驱体及产物的物性和结构进行表征。结果表明:钕元素已掺入到钴氧化物的晶格之中,形成了优良的软磁性钴钕复合氧化物。     

室温自交联丙烯酸酯乳液的合成及性能研究

采用半连续种子乳液聚合法,改性异构十三醇醚(H-606)与十二烷基硫酸钠(SDS)复配,以甲基丙烯酸(MAA)为功能单体,叔碳酸乙烯酯(VeoVa10)为改性单体,乙酰乙酸烯丙酯(AAA)与己二胺(HDA)为复配交联剂,合成了AAA-HDA/VeoVa10改性丙烯酸酯乳液.研究了AAA加料时间、AAA-HDA配比、AA...     

常温快速固化粘合剂的合成与应用

本文以改性环氧树脂、丁腈—40混炼胶液，钡酚醛树脂三组份按一定比例共混成甲组份，以多元胺类、酚类、醛类合成的一种固化剂为乙组仿，组成常温快固双组份粘合剂。文中介绍了胶的组份、制备方法、性能、粘接工艺等．探讨了固化机理。     

室温固相合成乙酰丙酮镍

以无机镍盐、固体碱、乙酰丙酮为原料,在室温无溶剂下采用固相研磨的方法合成乙酰丙酮镍。考察了镍盐、固体碱的种类、乙酰丙酮的物质的量对产率的影响。采用红外、热重对目标产物进行表征,结果与标准谱图基本一致。结果表明,硝酸镍、固体NaOH、乙酰丙酮按1∶4∶2物质的量比,在室温下研磨15 min所得产率最高,产率为85%。高于传统液相法产率的17%。     

室温磁制冷材料的研究进展

室温磁制冷材料的研究是室温磁制冷的关键因素,本文简述了磁制冷技术的发展前景以及基本原理,重点介绍了近年来室温磁制冷材料的研究进展。     

常温固相反应合成纳米氧化锌

以ZnSO4·7H2 O和Na2 CO3 为原料 ,用室温固相化学反应首先合成出粒径为 12 7nm的前驱体碳酸锌 ,然后在 2 0 0℃热分解 ,经纯化后得到纳米氧化锌。经XRD和TEM检测 ,粒径为 6 0～12 .7nm。     

磁性纳米粒子的制备和包覆

磁性纳米粒子由于其广泛的应用一直以来都是研究的热点。随着合成技术的不断发展,各种磁性纳米粒子均已成功制得,特别是合成形貌可控,高度稳定和单分散性的磁性纳米粒子。综述了磁性纳米粒子的几种比较常见的合成方法及其包覆措施,并对磁性纳米材料的应用进行了展望。