化学还原法制备不同形貌的纳米银粉

采用化学还原法,分别以还原糖溶液、聚乙二醇、三乙醇胺为还原剂制备纳米银粉,对还原机理进行了分析,探讨了还原剂种类、酸碱度pH值、溶液浓度、反应温度等对银粉形貌及粒度大小的影响。结果表明,分别以还原糖溶液、聚乙二醇、三乙醇胺为还原剂,制备了薄片状、棒状、类球形或线形纳米银粉,这主要与还原剂溶液的pH值有关。以三乙醇胺做还原剂40℃时,可以制得均匀的类球状纳米银粉。     

电子浆料用球形银粉制备工艺研究

采用化学还原法,以抗坏血酸为还原剂,明胶为分散剂,将硝酸银溶液滴加到还原性溶液中制备电子材料用球形高纯超细银粉。探讨了还原过程中各种因素如硝酸银溶液浓度、分散剂、反应温度、搅拌速度等对银粉粒度大小及分布的影响。采用TEM、SEM对所得银粉进行了表征。     

液相化学还原法制备超细银粉及其形貌研究

以抗坏血酸为还原剂,在水溶液中还原银的前驱物制备超细银粉。考察了前驱物和分散剂种类以及分散剂用量对银粉颗粒形貌的影响。通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对银粉产品进行结构及形貌表征。结果表明:以硝酸银和银氨溶液为前驱物,随着PVP加入量的改变,银粉颗粒由树枝状向球形状转变,PVP加入量为30%时,制备出的银粉颗粒分散性好,球形度高,颗粒粒径为0.94μm。     

低松装密度化学还原超细银粉生产

采用液相化学还原法,以甲醛为还原剂、高分子有机物为分散保护剂,将硝酸银溶液与还原性溶液混合生产低松装密度超细银粉,对其生产工艺的机理与特点进行了分析探讨,并对比介绍了其应用性能。     

还原-保护法制备纳米级银粉的研究

以氰化银钾 [KAg(CN) 2 ]为原料 ,抗坏血酸为还原剂 ,聚乙烯吡咯烷酮为保护剂和分散剂 ,将还原剂和保护剂在反应体系之外预混合 ,然后滴加到KAg(CN) 2 溶液中 ,制备出粒径分布范围为 2 0～ 30nm的银粉 ,分散剂加入到还原剂中预先混合所得银粉的平均粒径约为分散剂预先加入在原料体系中所得银粉平均粒径的 1 14,在反应温度为 35 3K前随着反应温度的增加银粉粒径逐渐减小 ,超过 35 3K后银粉粒径随反应温度的增加而增加 ,在 35 3K时反应所得银粉的粒径最小。固定还原剂和原料浓度之比 (4 9∶1 0 ) ,在其他条件相同时银粉粒径随着反应物浓度的增加而增加。反应所得银粉用油酸钝化 ,可有效地防止银粉的氧化。用透射电镜 (TEM)和紫外 -可见分光光度计 (UV -Vis)等测试手段对所制得的纳米级银粉进行了表征     

专利介绍

<正>含短棒状纳米银粉导电胶CN101 215 450(2008-07-09)。该导电胶的组成及质量分数为:聚合物基体环氧树脂24%～40%,导电银粉微粒50%～70%(其中短棒状纳米银粉10%、微米银粉40%～60%),增塑剂邻苯二甲酸二丁酯2.4%～4.0%,固化剂三乙醇胺3.6%～6.0%。纳米银粉的制备是以硝酸银、聚乙烯吡咯烷酮表面活性剂和5%水合肼还原剂为原料,经液相还原反应而制得;其中m(硝酸银)∶m(聚乙烯吡咯烷酮)=1∶1。由于体     

聚乙二醇在银粉制备中的应用

以乙醇为溶剂,PVP为保护剂,研究非离子表面活性剂聚乙二醇在银粉制备过程中的分散作用,并采用扫描电镜(SEM)和X射线衍射等对还原产物进行形貌观察和结构表征。结果表明:PEG对制备样品的纯度、分散性和颗粒大小有着重要的影响。在一定聚合度范围内,聚乙二醇相对分子质量大,分散效果好。采用PEG-400分散剂可制备出高分散、窄粒级的超细银粉。随着聚合度的增大,聚乙二醇在乙醇中溶解度下降,降低了其分散性能。     

表面活性剂对微米银粉的粒径与形貌的影响研究

以硝酸银为银源,抗坏血酸为还原剂,采用超声辅助液相还原法制备微米级银粉颗粒,研究了聚乙烯吡咯烷酮(PVP和阿拉伯树胶(AG)复合表面活性剂的质量配比和添加量对银粉特性的影响.利用扫描电子显微镜、X射线衍射仪、激光粒度仪以及振实密度计对银粉的形貌、物相、粒度和振实密度进行了测试.结果表明,PVP与AG的复合物对改善银粉的...     

超细银粉及导电复合材料制备与表征

为了制备相对较低固化温度银导电复合材料,采用AgNO_3为银源,液相还原法制备了球形超细银粉。导电复合材料主要由超细银粉和有机载体组成,并系统研究了制备工艺对银导电复合材料性能的影响。结合X射线衍射(XRD)、透射电镜(TEM)、扫描电镜(SEM)、热分析(DSC/TG)等分析手段,研究了银粉的晶体结构、形貌及导电复合材料的电性能、强度和形貌。结果表明,球形超细银粉的平均粒径为150 nm,粒径分布在50~200 nm,呈立方晶体结构。推荐最佳的导电复合材料制备薄膜工艺为:70%银粉、30%的有机载体,在150℃的温度下固化30 min,该薄膜的电阻率为5.2×10~(-4)?·cm。     

喷墨导电墨水用超细纳米银粉的制备

以C_6H_8O_6(抗坏血酸)为还原剂、PVP(聚乙烯吡咯烷酮)为分散剂,采用液相还原AgNO_3(硝酸银)溶液法制备了喷墨导电墨水用超细纳米银粉。研究结果表明:当AgNO_3浓度为1.0 mol/L、n(C_6H_8O_6)∶n(C_6H_8O_6理论值)=1.5∶1、n(PVP)∶n(AgNO_3)=1.2∶1和反应温度为40℃时,可制得分散均匀、纯度较高的超细纳米银粉;该纳米银粉的平均粒径小于10 nm,可以满足喷墨印刷的工艺要求。     

液相化学还原法制备单分散的纳米银粒子

以月桂酸为修饰剂,水合肼为还原剂,银氨溶液为银源,在水相中利用液相化学还原法制备了单分散的粒径分布均匀的纳米银粒子。利用透射电子显微镜(TEM)、X射线衍射(XRD)对样品的形貌和结构进行了分析,研究表明,修饰剂与硝酸银的质量比、反应温度对纳米银形貌及粒径有很大影响。当修饰剂与硝酸银的质量比为1.2∶1、反应温度为室温时,能够制备平均粒径为8 nm、粒径均匀、单分散的纳米银粒子。另外,UV光谱也证实,所制的溶胶为粒径均匀的纳米银溶胶。     

Preparation and application of silver nanoparticles on silk for imparting antimicrobial properties

Silver nanoparticles were produced by a chemical reduction method that reduced silver nitrate with reducing agents such as hydrazine and glucose. The silver nanoparticles were characterized with transmission electron microscope, scanning electron microscope, and optical microscope. The effects of process parameters such as the stirring speed, temperature, type of reducing agent, and dispersing agent on the particle size were studied. The particle size decreased with an increase in the stirring speed and a decrease in the process temperature. Smaller particles were formed when the silver nitrate was reduced by glucose versus those that were formed by reduction with hydrazine. Silver nanoparticles with average sizes of 10 and 35 nm, produced by reduction with hydrazine at 5 and 40°C, were applied to silk by an exhaust method. Silk fabrics treated with 40 ppm silver hydrosol produced at 5°C and 60 ppm silver hydrosol produced at 40°C showed 100% antimicrobial activity against the gram‐positive bacterium Staphylococcus aureus. The durability of the antimicrobial property of the treated silk fabric to washing was also examined and is presented. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

电磁屏蔽导电涂料用镀银铜粉的制备

采用置换反应法制备镀银铜粉时,铜粉还原银氨溶液中的Ag+生成的Cu2+与NH3形成络合物[Cu(NH3)4]2+,它吸附于铜粉表面而阻碍还原反应的继续进行,使制备的镀银铜粉表层的银含量降低。用氨水提高银氨溶液的pH,可增加制备的镀银铜粉表层的银含量,提高其抗氧化性能。当用氨水调节银氨溶液的pH至11.50时,可制得表层银的质量分数高达47.91%且具有常温抗氧化性能的镀银铜粉。研究了pH、AgNO3用量、AgNO3浓度和反应温度对镀银铜粉的抗氧化性能的影响。     

植物副产物浸出分离氧化型锰银矿的研究

介绍了利用植物副产物（秸秆、粮食加工副产壳类等）作为还原剂还原浸出氧化型锰银精矿中的锰、浸锰渣氰化浸银的锰银分离工艺。玉米秸秆还原浸锰条件：秸秆粉在95 ℃预降解糖化0.5 h、降解糖化液与精矿的体积质量比为3 mL/g、硫酸与锰的物质的量比为1.4、秸秆与精矿的质量比为0.275、95 ℃浸出5 h,在此条件下锰的浸出率约92%。浸锰渣氰化浸银条件：每吨浸锰渣氰化钠用量为3 kg、常温浸银3 h,在此条件下银的浸出率达到92.20%。研究的锰银分离工艺具有较好的综合效果。     

Preparation of acacia‐stabilized silver nanoparticles: A green approach

We report a facile approach for the spontaneous formation of silver nanoparticles in the presence of gum acacia polymer (a natural polymer) without the addition of any typical reducing agent under mild conditions. Silver nanoparticles (～ 5 nm) have been obtained by the mixing of equal amounts of 0.5 wt % aqueous solutions of acacia and silver nitrate. The formation of silver nanoparticles has been confirmed with ultraviolet–visible, Fourier transform infrared, X‐ray diffraction, and X‐ray photoelectron spectroscopy analyses. Gum acacia polymeric chains promote the reduction process and act as good stabilizers over 5 months. To confirm the formation and stabilization of the nanoparticles, a transmission electron microscope has been employed. The advantage of this methodology is that it is possible to prepare silver nanoparticles without any organic solvents or reducing agents. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

石墨烯负载纳米银的制备及其对H2O2的电化学检测

采用改进的Hummers法制备了氧化石墨烯（GO）,然后以水合肼作为还原剂,并控制反应的pH=10来制备还原氧化石墨烯（RGO）。采用化学还原法,以石墨烯为载体,以乙酰丙酮银为前体,以硼氢化锂四氢呋喃溶液为还原剂将银离子还原,制备了石墨烯负载纳米银复合材料。通过X 射线粉末衍射（XRD）、傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）等表征方法证明了石墨烯上负载的银纳米颗粒结晶良好、尺寸均一、分布均匀,其中银纳米颗粒直径约为8nm。通过循环伏安和计时电流技术对石墨烯负载纳米银复合材料进行电化学测试,结果表明,石墨烯负载纳米银复合材料对过氧化氢的还原具有良好的电催化活性。以此复合纳米结构构建的过氧化氢传感器测试过氧化氢浓度的线性范围为0.1～62.3mmol/L（R=0.990）,检出限为0.017mmol/L（S/N=3）,响应时间小于2s。     

Silver nanoparticles deposited on polysiloxane networks as active catalysts in dye degradation

The article proposes a new method of obtaining silver nanoparticles on polysiloxane networks using the reducing properties of Si–H groups. Three types of networks with different architecture and distribution of Si–H groups were studied as reducing agents for silver ions and as matrices for the obtained silver nanoparticles. As established by FTIR spectroscopic studies, the redox reaction between Ag⁺ ions from the silver heptafluorobutyrate solution in toluene and Si–H groups of the networks occurred, which resulted in the appearance of silver nanoparticles in the systems. The amount of metal introduced into individual polysiloxane networks is closely related to the consumption of Si–H groups in them. The type of polysiloxane networks used affects the size of Ag NPs obtained and their distribution on the carrier. Polysiloxane-Ag systems are observed to be an effective catalyst on reduction of hazardous dye like methyl red, which is confirmed by a decrease in absorbance maximum values.     

用SiO2微粉制备碳化硅粉体的研究

为回收利用SiO2微粉,探究了以SiO2微粉为原料通过碳热还原法制备碳化硅粉体的最佳工艺条件;研究了分别以石油焦、活性炭和石墨粉为还原剂对冶炼效果的影响。在最佳碳质还原剂的基础上,研究了不同配碳比(还原剂与SiO2微粉的质量比为1∶3.5、1∶3、1∶2.5、1∶2、1∶1.5)和不同冶炼时间(15、30、45、60 min)对冶炼效果的影响。结果表明:石油焦、活性炭、石墨粉3种碳质还原剂中,石油焦的冶炼效果最佳;将石油焦与原料SiO2微粉以质量比1∶2进行混合,在中频感应炉中以1650℃冶炼45 min为最佳冶炼工艺条件;以此能够得到晶粒生长较好、品质较高的碳化硅粉体,碳化硅含量高达93.50%(w)。     

Synthesis of silver particles below 10 nm using spinning disk reactor

Silver nanoparticles were synthesized via a reduction reaction carried out in a spinning disk reactor, to which an AgNO₃ solution containing a protecting agent and an alkaline solution containing a reducing agent were added simultaneously and then recycled for a certain period. Besides starch, which has been used for producing silver particles above 10 nm, two more protecting agents, i.e. polyvinyl pyrrolidone (PVP) and hydroxypropyl methyl cellulose (HPMC), were tested in order to prepare silver particles below 10 nm. Then, the effects of other operating variables, such as rotation speed of disk, flow rates of reactant streams, concentration of reducing agent, and type and concentration of alkali, were investigated, aiming at a high production rate of silver nanoparticles with a size below 10 nm. The produced silver particles were recovered using a centrifuge, and the size did not change after redispersion. The sintering temperature of the 10 nm silver particles was greatly reduced.