纳米银与基体P(AMPS-MMA)的相互作用研究

在无引发剂和还原剂的条件下超声辐射双原位合成出纳米银/2-丙烯酰氨基-2-甲基丙磺酸与甲基丙烯酸甲酯共聚物[P(AMPS-MMA)]复合物.TEM表明,纳米银粒子的粒径5~15nm,均匀地分散在聚合物基体中;UV-Vis表明,超声时间影响纳米银的粒径大小及粒径分布;FT-IR、UV-Vis和荧光光谱表明纳米银与基体P(AMPS-MMA)之间存在一定的化学作用力;XPS证明了纳米银与基体P(AMPS-MMA)的作用力为纳米银与聚合物中酯基氧原子之间通过配位作用形成的化学作用力.     

PVP催化还原及稳定化纳米银的微波合成

在聚乙烯基吡咯烷酮(PVP)的存在下,微波辐射硝酸银水溶液,合成了纳米银/PVP复合物。UV-Vis和XRD结果证明了生成的纳米银具有面心立方结构,PVP中N原子对银离子具有催化还原作用。TEM结果表明纳米银粒径在10～25nm,且较均匀分散在聚合物基体中;XPS结果表明PVP与纳米银之间存在相互作用。     

壳聚糖纳米银溶液的稳定性及在织物抗菌整理上的应用

采用化学还原法在不同浓度的壳聚糖醋酸溶液中以硼氢化钠还原硝酸银, 制备了系列壳聚糖纳米银溶液; 考察了不同质量分数的壳聚糖溶液对纳米银的浓度、 形貌和粒径大小的影响及纳米银的稳定性. 采用紫外-可见吸收光谱、 原子吸收光谱和透射电子显微镜对所得溶液进行表征, 结果表明, 当有壳聚糖存在时, 纳米银以小于50 nm球形粒子稳定分布于壳聚糖溶液中. 随着壳聚糖质量分数的增大, 形成纳米银浓度减小, 但稳定性提高, 壳聚糖质量分数控制在0.5%~0.7%范围内, 可得到浓度较高且稳定性良好的纳米银. 在壳聚糖和纳米银的共同作用下织物具有极好的抗菌性和抗菌长效性.     

原位法制备纳米银修饰碳纳米管环氧导电复合材料

将碳纳米管(CNTs)和乙酸银同时引入到环氧树脂-咪唑固化体系中,在固化过程中原位热降解银-咪唑复合物生成纳米银修饰碳纳米管,差示扫描量热仪(DSC)表明改性碳纳米管对环氧固化有一定的促进作用.采用X-射线衍射(XRD)表征了乙酸银和咪唑配合物[Ag(2E4MZ)2]Ac的结构,并提出了原位降解生成纳米银的机理.XRD结果表明,单独的乙酸银-咪唑配合物热降解生成的纳米银粒径为21-24nm,而配合物在环氧基体中生成的纳米银粒径为11-13nm.添加80%(质量分数)片状微米银粉制备的纳米银/碳纳米管环氧导电复合材料其体积电阻率低达9×10-5Ω·cm.当纳米银和碳纳米管质量比为80:20时,复合材料导电性和剪切强度达到最佳;采用扫描电镜(SEM)表征了复合材料的形貌结构.     

抗氧化剂没食子酸丙酯合成纳米银及其应用

在十六烷基三甲基溴化铵(CTAB)存在下, 硝酸银与没食子酸丙酯在碱性介质中发生还原反应, 制得纳米银; 考察了反应时间、 氢氧化钠浓度、 反应温度以及PG/Ag⁺浓度比等条件对合成纳米银粒子的影响. 利用扫描电子显微镜对纳米银颗粒形貌和尺寸进行了表征, 结果表明获得了分散性良好的球形粒子. 实验中还发现在还原银离子制备纳米银过程中会产生强烈的表面等离子共振峰, 用紫外-可见光谱监测制备过程得到的纳米银紫外吸收带范围为400~450 nm, 最大吸收波长为420 nm, 光谱强度与抗氧化剂的浓度成正比. 将纳米银的这一特性用于定量测定没食子酸丙酯(PG)、 二丁基羟基甲苯(BHT)、 叔丁基对羟基茴香醚(BHA)和叔丁基对苯二酚(TBHQ)等抗氧化剂, 所得检出限分别为0.0752, 0.1242, 0.0693和0.0701 mg/L, 线性范围分别为0.2~1.8, 0.2~3.4, 0.2~3.4和0.2~3.0 mg/L.     

乙酰乙酸基聚丙烯酸酯与端烯基聚氨酯交联反应机理

乙酰乙酸基聚丙烯酸酯与端烯基聚氨酯交联反应机理唐黎明＊郭伟刘德山周其庠（清华大学化工系北京１０００８４）关键词乙酰乙酸基，聚丙烯酸酯，聚氨酯，双键，交联机理１９９６－０８－２０收稿，１９９６－１２－０５修回近年来，含有乙酰乙酸基团的聚合物在涂料、粘合...     

纳米银的绿色合成: 丝胶蛋白作为还原剂和分散剂

利用基于天然生物高分子的绿色环保法制备纳米贵金属材料是当今纳米技术发展的一个重要方向之一. 利用丝胶蛋白(SS)为还原剂和分散剂合成了纳米银颗粒, 利用紫外-可见(UV-Vis)光谱、X射线衍射(XRD)、透射电镜(TEM)等研究了反应温度、pH值、SS/Ag^＋物质的量比对反应速率和合成的纳米银粒子形貌的影响. 实验结果表明, 利用本方法可以合成尺寸均匀且分散性良好的球形纳米银粒子, 且随着反应温度和溶液pH值的逐渐升高, 反应速率随之加快, 合成的纳米银粒子的粒径逐渐变小, 而SS/Ag^＋物质的量比的变化主要对纳米银粒子的尺寸有影响.     

琥珀酸二异辛酯磺酸钠微乳体系中纳米银的制备及其连续相的影响

在琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂、环己烷为连续相形成的微乳体系中, 利用水合肼还原AgNO₃制备了分散性良好的纳米银. 利用紫外-可见(UV-Vis)光谱和透射电镜(TEM)对所得产物进行了表征, TEM显微图像表明形成粒子为球形结构, 平均粒径为5.10 nm, 标准偏差为2.84 nm. 分别利用正己烷、正庚烷、正辛烷、环己烷和十二烷等作连续介质, 研究了微乳液中连续相对纳米银形成的影响. 随着正烷烃碳链长度的增加, 微乳液中胶束之间的交换速率增大, 形成粒子的平均粒径逐渐减小. 十二烷形成的微乳体系制备的纳米银溶胶具有最宽的共振吸收峰, 所得的纳米银粒子平均粒径最小. 环己烷形成的微乳液中反胶束具有特殊的界面强度, 导致纳米银晶核的形成速率过低, 纳米银晶粒的生长不完全.     

银/聚合物纳米复合材料

银/聚合物纳米复合材料是一种典型的聚合物基复合材料, 其结构和性能依赖于合成方法,因此开发材料的优异性能必须以深入研究纳米材料的先进合成技术为前提。本文综述了纳米银粒子及其与聚合物形成的纳米复合材料的最新合成进展, 重点介绍了基于液相化学还原方法合成纳米银粒子的新方法, 如溶胶-凝胶法、沉淀法、微乳液法和离子液体法, 以及纳米银粒子的分散技术和原位法合成银/聚合物纳米复合材料的新技术, 并介绍了纳米银复合材料的电绝缘性、表面增强拉曼散射性能、抗菌性及其在生物医学等领域中的应用。     

球形纳米银与人血清白蛋白相互作用的研究

通过化学还原法合成了球形银纳米颗粒,并利用电子显微镜方法对其形貌进行了表征;利用紫外可见吸收光谱法(UV)、荧光光谱法(FL) 以及扫描电子显微镜(SEM) 研究了球形纳米银与人血清白蛋白(HSA) 的结合反应。随着纳米银溶液浓度的增加,混合溶液的紫外吸收峰强度增加,但荧光强度则发生了明显的猝灭。光谱学实验结果表明,球形纳米银与人血清白蛋白在溶液中发生了相互作用,此结果也通过扫描电子显微镜实验得到了验证。由荧光实验还可获得纳米银与HSA 相互作用的结合常数、结合位点数以及吉布斯自由能变,由这些热力学数据可知纳米银与人血清白蛋白可以自发结合发生反应,并形成缔合物。     

Synthesis and characterization of silver—poly(methylmethacrylate) nanocomposites

The optical properties of silver nanoparticles embedded in poly(methylmethacrylate) (PMMA) was investigated as well as the influence of silver nanoparticles on the thermal properties of polymer matrix. The average size and particle size distribution of silver nanoparticles was determined using transmission electron microscopy. The obtained transparent nanocomposite films were optically characterized using UV-Vis and FTIR spectroscopy. Thermal stability of polymer matrix was improved upon incorporation of small amount of silver nanoparticles. Also, silver nanoparticles have pronounced effect on thermo-oxidative stability of PMMA matrix. The glass transition temperatures of nanocomposites are lower compared to the pure polymer.     

Preparation of antibacterial polyimide films containing silver nanoparticles

Polyimide/silver composite films were successfully prepared by in situ polymerization. A precursor, AgNO₃ was used as the source of the silver nanoparticles. The structure and morphology of resulting films were characterized by FTIR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Consequently, the silver nanoparticles were well dispersed in polyimide matrix. Meanwhile, thermal properties from thermal gravimetric analyses (TGA) and mechanical properties from tensile test which confirmed composites were kept good performance as compared to pure polyimide. In addition, the antimicrobial activity of polyimide/silver composite films against three different bacteria, B. subtilis, S. aureus, and E. coil, illustrated excellent activity. This composite is potential useful as antimicrobial material with good thermal performance in a wide variety of biomedical and general use applications.     

Nanostructured polyamic acid membranes as novel electrode materials

This paper describes a new approach for the preparation of polyamic acid (PAA) composites containing Ag and Au nanoparticles. The composite film of PAA and metal particles were obtained upon electrodeposition of a PAA solution containing gold or silver salts with subsequent thermal treatment, while imidization to polyimide is prevented. The structural characterization of the films is provided by 1H NMR and Fourier transform infrared spectroscopy (FTIR), while the presence of metallic nanoparticles within the polymeric matrix was confirmed by scanning electron microscopy (SEM), cyclic voltammetry (CV), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). This approach utilizes the unique reactivity of PAA by preventing the cyclization of the reactive soluble intermediate into polyimides at low temperature to design polymer-assisted nanostructured materials. The ability to prevent the cyclization process should enable the design of a new class of electrode materials by use of thermal reduction and/or electrodeposition.     

Preparation and physicochemical properties of hydroxyapatite/polyurethane nanocomposites

In this study, nanohydroxyapatite/polyurethane （nHA/PU） composites with various contents of methoxy- poly（ethylene glycol） modified nHA （0 wt%, 10 wt%, 20 wt% and 30 wt%） were prepared by solution blending process. The physicochemical properties of the composite membranes were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffraction （XRD）, Transmission electronic microscopy （TEM）, Differential scanning calorimetry （DSC）, Thermo gravimetric analysis （TGA） and tensile tests. TEM photos of the nanocomposites showed that the nHA was uniformly dispersed in the polymer matrix. The membrane with 10 wt% nHA showed the highest tensile strength which was about 75% higher than that of the pure PU membrane. However, the tensile strength decreased when high content （above 20 wt%） fillers were added, which was still higher than that of pure PU. TGA measurements suggested that the thermal stability of the membranes was improved owing to nHA fillers. XRD and DSC results illustrated that the crystallinity of PU soft segments decreased with the increasing content of nanoparticles in the composites.     

Study on luminescence characteristic of the ZnO/polymer hybrid films

The cyclohexane solution of PS (polystyrene) and the ethyl acetate solution of PMMA (polymethyl methacrylate) were used as flowing liquid; the ZnO/polymer hybrid colloids were successively produced by focused pulsed laser ablation of ZnO target in interface of solid and flowing liquid. As solvent in the hybrid colloids has volatized, the ZnO/polymer hybrid films were obtained. The hybrid colloids were characterized by high-resolution transmission electron microscopy (HRTEM) and select-area electron diffraction (SEAD). The results show a good dispersion of the ZnO nanoparticles in the polymer matrix. The hybrid films were characterized by fluorescence spectrum, Fourier transform infrared spectroscopy (FTIR) spectroscopy, thermogravimetry with FTIR (TG/FTIR), and X-ray photoelectron spectrum. The results show the ZnO/polymer hybrid films can radiate strong blue light under ultraviolet. Meanwhile, the ZnO/polymer hybrid films have higher chemical stability than ZnO nanoparticles because nano-ZnO nanoparticles were enwrapped by polymers. In addition, the ZnO hybrid films have higher thermal stability then the related pure polymers because of strong interaction among ZnO nanoparticles and polymers.     

溶胶-凝胶法制备Polyme/MS/SiO2(M=Pb,Cd)复合纳米材料

采用溶胶-凝胶结合水热结晶技术,可成功把高聚物引入MS-SiO2网络结构,合成一种新型的有机-无机硫化物即Polymer/MS/SiO2(M=Pb,Cd)复合纳米材料,其中聚甲基丙烯酸甲酯或聚丙烯酰胺等高聚物的引入将有效地防止无机粒子团聚,控制粒子尺寸,前者还能形成核-壳结构复合粒子.作者还详细讨论了该复合纳米材料的热分析,结果表明,聚合物的存在提高了原有MS-SiO2(M=Pb,Cd)材料的热稳定性.     

氮掺杂还原氧化石墨烯负载铂催化剂的制备及甲醇电氧化性能

采用高温热解聚苯胺修饰的氧化石墨烯(PANI-GO),得到了氮掺杂的还原氧化石墨烯碳材料(N-RGO),以其负载Pt制备了Pt/N-RGO纳米结构电催化剂.采用透射电镜(TEM)、X射线光电子能谱(XPS)、X射线衍射(XRD)谱及拉曼光谱等技术对N-RGO和Pt/N-RGO的形貌及结构进行了表征,用循环伏安、计时电流等电化学技术研究了Pt/N-RGO电极催化剂对CO溶出反应和甲醇电氧化反应的催化性能.结果表明:高温热解PANIGO可同时实现GO的还原及其氮掺杂的过程,氮掺杂引起还原氧化石墨烯碳材料表面缺陷结构和导电性的增加;与相应的未掺杂氮样品Pt/RGO相比较,Pt/N-RGO样品上Pt颗粒的分散更均匀,显示出更强的抗CO毒化能力和更高的甲醇电氧化催化活性及稳定性.     

In situ sol–gel preparation of high transparent fluorinated polyimide/nano-MgO hybrid films

Hybrid nanocomposite films of magnesium oxide (MgO) in fluorinated polyimide (PI) from 4, 4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4, 4′-Diaminodiphenyl ether (ODA) have been successfully fabricated via an in situ sol–gel polymerization technique. The MgO content in hybrid films was varied from 0 to 5 wt%. The hybrid films were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), ultraviolet–visible (UV–Vis) spectroscopy and thermal gravimetric analyses (TGA). The results of FTIR, XRD and FESEM showed that the MgO nanoparticles were well dispersed in the polymer matrix due to the coordination between the carbonyl group of polymers and Mg atom, and the as-prepared hybrid films exhibited excellent optical transparency in the visible region and good UV-shielding properties in the UV region. Although the thermal stability of the hybrid films is slight inferior to pure PI, it is still good for the practical application below the temperature of 300 °C.     

氮掺杂还原氧化石墨烯负载铂催化剂的制备及甲醇电氧化性能

采用高温热解聚苯胺修饰的氧化石墨烯（PANI-GO）,得到了氮掺杂的还原氧化石墨烯碳材料（N-RGO）,以其负载Pt 制备了Pt/N-RGO纳米结构电催化剂. 采用透射电镜（TEM）、X射线光电子能谱（XPS）、X 射线衍射（XRD）谱及拉曼光谱等技术对N-RGO和Pt/N-RGO的形貌及结构进行了表征,用循环伏安、计时电流等电化学技术研究了Pt/N-RGO电极催化剂对CO溶出反应和甲醇电氧化反应的催化性能. 结果表明：高温热解PANIGO可同时实现GO的还原及其氮掺杂的过程,氮掺杂引起还原氧化石墨烯碳材料表面缺陷结构和导电性的增加;与相应的未掺杂氮样品Pt/RGO相比较,Pt/N-RGO样品上Pt 颗粒的分散更均匀,显示出更强的抗CO毒化能力和更高的甲醇电氧化催化活性及稳定性.     

CdS/石墨烯复合材料的制备及其可见光催化分解水产氢性能

以氧化石墨烯和CdS为原料, 在乙醇水溶液中采用CdS光催化还原法制备了CdS/石墨烯复合光催化材料, 并用透射电子显微镜(TEM)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、X射线光电子能谱(XPS)和瞬态光电流等技术对复合材料的结构和光电性能进行了表征. 可见光照射下(λ≥420 nm), 研究了该复合材料光催化分解水产氢的性能. 结果表明, 可见光照射下CdS的光生电子可有效地还原氧化石墨烯, 得到CdS与石墨烯之间具有强相互作用力的CdS/石墨烯复合材料. 与CdS相比, 复合材料中石墨烯作为良好的电子受体和传递介质, 可明显加快CdS光生电子的迁移速率, 提高光生载流子的分离效率, 从而增强复合材料的光电性能和光催化分解水产氢的活性.