Dendrimer Templates for the Formation of Silver Nanoparticles

Synthesisandcharacterizationofmetalnanopar ticles,especiallynoblemetalnanoparticleshaveat tainedgreatconsiderationowingtotheiroptical,elec tronic,andcatalyticproperties[1,2].Theabundant literatures[3,4]showthattheoptical,electronic,and catalyticpropertiesofthemetalnanoparitclesdepend ontheirsizeandstability,whichstronglydependon themethodandexperimentfollowed.Soitisimpor tanttochooseapropermethodtopreparenoble nanoparticles.Dendrimers[5]arehighlybranched macromoleculesthatconsistofacentralcore…     

聚酰胺胺(PAMAM)树形分子用作乳化炸药的稳定剂

用PAMAM树形分子作稳定剂制成了一种新型的乳化炸药,并用高低温循环及室温贮存的电导率测试、扫描电镜等技术对其稳定性作了表征.结果表明,用PAMAM稳定后的乳化炸药具有很好的稳定性,对该乳化炸药的爆速测试结果表明,添加PAMAM后的乳化炸药的爆速反而增加.同时,对此乳化炸药的稳定机理作了初步探讨.     

酸碱滴定分析在聚酰胺-胺表征中的应用

整数代聚酰胺-胺(PAMAM)树形分子含有末端伯胺基及内部有叔胺基,酸碱滴定分析可以表征伯胺基及叔胺基的数量。文中详细讨论了该方法的原理,说明滴定过程中产生的酰胺键水解不影响滴定及计算结果。滴定分析在不同初始pH条件下进行,通过实验表明,在pH<2的条件下滴定可以保证叔胺的充分质子化。     

硼钨铜杂多酸/聚酰胺-胺多层膜的制备及其电催化性能

通过层层自组装技术在氧化锢锡(ITO)电极上制备Keggin型硼钨铜杂多酸/聚酰胺-胺有机-无机复合多层膜.利用X射线光电子能谱(XPS),UV-Vis光谱和原子力显微镜(AFM)等手段对多层膜的组成和表面形貌进行了表征.结果表明,杂多酸阴离子和聚酰胺-胺树形分子通过静电相互作用形成了多层膜且膜的增长均匀.杂多酸阴离子...     

微波合成树枝状高分子聚酰胺-胺及其荧光性质

采用微波法合成了PAMAM,反应时间由常温下的24 h缩短到数十分钟,并研究了产物的荧光性质,微波下合成产物随代数增加有一定的线性变化规律,并初步研究了PAMAM与药物的相互作用。     

Water-soluble porphyrin-PAMAM-conjugates of melphalan and their anticancer activity

p-[bis(chloro-2-ethyl)amino]-L-phenylalanine (melphalan) is an approved anti-cancer agent with a broad spectrum of antitumor activity. However, it has some disadvantages, such as poor water-solubility followed by rapid elimination, which reduce the target specificity. To solve these problems, porphyrin- poly(amidoamine) or PAMAM-conjugates of melphalan were synthesized and characterized. The dendrimeric conjugates showed satisfactory water solubility. It was found that the size of the dendrimer played a crucial role in controlling the drug content and diameter of the melphalan-conjugates. The in vitro studies of cell cytotoxicity revealed that by employing the dendrimeric conjugation strategy and using the PAMAM dendritic arms as spacers, the conjugates had good anti-cancer activity and lower toxicity than free melphalan.     

Diphenolic acid-modified PAMAM/chlorinated butyl rubber nanocomposites with superior mechanical,damping, and self-healing properties

ABSTRACT

Based on its excellent damping properties, traditional rubber has been widely used in various industries, including aerospace, rail transit and automotive. However, the disadvantages of effective damping area, unstable damping performance, easy fatigue, and aging, greatly limited the further application of rubber materials. Thus, it is important to develop novel modified rubber damping materials. Herein, polyamidoamine dendrimers with terminal-modified phenolic hydroxyl and amine groups (G2 PAMAM-H) were designed and used as modifiers to improve the damping performance of chlorinated butyl rubber (CIIR). The results showed that the modification of G2 PAMAM by diphenolic acid can avoid its aggregation in the CIIR matrix. CIIR/G2 PAMAM-H nanocomposites exhibited high tan δ _max of 1.52 and wide damping temperature region of 140°C (tan δ > 0.55)at a very low loading (4.32 wt.%), which were strongerthan that of pure CIIR and CIIR/G2 PAMAM nanocomposites. In addition, these nanocomposites also exhibited a unique self-healing ability by multiple hydrogen bonds, which can effectively extend the life of the rubber material in actual production. Therefore, the dendrimer modification provided unique development opportunities for elastomers in certain highly engineered fields, such as vehicles, rail transit, aerospace, etc.     

树状分子聚酰胺胺(PAMAM)的量子化学研究

采用传统的Hartree-Fock(HF)从头算和密度泛函B3LYP方法,选择不同的基组水平(3-21G,6-31G*)对以乙二胺为核的1.0代PAMAM分子进行全几何优化,并对结果进行比较,同时与实验值进行对照.结果表明,B3LYP/6-31G*方法得到的结果更可靠.B3LYP/6.31G*计算结果表明,1.0代PAMAM分子构象不完全对称,4个支链基本在一个平面上,伯胺,仲胺和叔胺上的N原子所带负电荷数逐渐减少,HOMO轨道主要集中在核上,核极易发挥供电子作用.     

新型除油剂的合成及性能研究

采用共沉淀法合成纳米四氧化三铁,然后通过PAMAM树状大分子表面包覆合成了PF系列除油剂,探索了不同反应条件对其除油性能的影响,得到了合成PF系列除油剂的最适宜条件:n(PAMAM):n(总Fe)=5,反应温度为70℃,pH为8～9,反应时间30min.透射电子显微镜表明得到的产物是粒径为30 nm左右的四氧化三铁颗粒.这种新型除油剂在加剂量为70mg·L~(-1)时,可将孤四联污水含油量从1273.6mg·L~(-1)降到35.7mg·L~(-1),除油率达97.2%,悬浮物从145mg·L~(-1)降到58mg·L~(-1),现场使用的药剂罗曼哈斯的出油率只有87.2%,研究表明PF系列除油剂对孤岛三个联合站的污水有一定的普遍适应性.     

Spectroelectrochemical analysis of ion-transfer and adsorption of the PAMAM dendrimer at a polarized liquid|liquid interface

The interfacial behavior of the fourth generation polyamidoamine (G4 PAMAM) dendrimer at a water|1,2-dichloroethane (DCE) interface was studied by cyclic voltammetry and potential modulated fluorescence (PMF) spectroscopy. Irregular voltammetric responses were observed at positively polarized interfaces. The cyclic voltammogram was strongly dependent on pH and on the concentrations of the G4 PAMAM dendrimer and the organic supporting electrolyte. PMF spectroscopy was successfully used to analyze the interfacial mechanism of the dendrimer by adding an anionic porphyrin derivative as a fluorescent probe. The results of the PMF measurements demonstrated that the G4 PAMAM dendrimer was transferred across the interface, a process that was accompanied by an adsorption step at pH 7. In contrast, under alkaline conditions, the adsorption process did not seem to be involved in the interfacial behavior.