树枝形聚酰胺胺对尼龙6性能影响的研究

研究4．0代树枝形聚酰胺胺（PAMAM）对尼龙6拉伸性能、冲击性能及熔体流动速率的影响。结果发现，在尼龙6中添加PAMAM后，尼龙6的拉伸强度、断裂伸长率、缺口冲击强度及熔体流动速率均有所提高，PAMAM添加量为1．0％时效果最佳。PAMAM与尼龙6之间强烈的相互作用，以及两相界面上形成的密实薄层，是尼龙6力学性能提高的原因。     

Poly(amidoamine) dendrimers with phenyl shells: fluorescence and aggregation behavior

The fluorescence and aggregation behavior of poly(amidoamine) (PAMAM) dendrimers modified with phenyl groups at the periphery (PAMAM-P) were investigated. For comparison, the third generation (G3) PAMAM dendrimer with a shell of positive charge (PAMAM-PA) was also synthesized. PAMAM-P G3, G4 and G5 show dual fluorescence emission due to the fluorescence emission of phenyl ring and its excimer. By increasing the generation number from G2 to G4, the fluorescence intensity of phenyl ring decreases, and the fluorescence of phenyl excimer appears and becomes obvious. The three-dimensional geometry arrangement or dendrimer architecture was found to have a strong effect on their fluorescence behavior. This result is further supported by the solvent effect and model compound studies. The lower generations (PAMAM-P G0 to G3) were self-organized into spherical aggregates. However, no aggregation behavior was observed for the higher generations (>G3). The critical aggregation concentration (CAC) values measured by fluorescence spectroscopy were found to decrease gradually with increasing generation number from G0 to G3.     

Liver‐targeting doxorubicin‐conjugated polymeric prodrug with pH‐triggered drug release profile

The aim of the research presented was to develop a potential liver‐targeting prolonged‐circulation polymeric prodrug of doxorubicin (Dox) with a pH‐triggered drug release profile. In particular, linear dendritic block copolymers composed of polyamidoamine dendrimer (PAMAM) and poly(ethylene glycol) (PEG; number‐average molecular weight of 2000 g mol^?1) with or without galactose (Gal) were synthesized. Dox was coupled to the copolymers via an acid‐labile hydrazone linker. These prodrugs, designated Gal‐PEG‐b‐PAMAM‐Dox_n and mPEG‐b‐PAMAM‐Dox_m, showed accelerated Dox release as the pH decreased from 8.0 to 5.6. Cytotoxicity of the prodrugs was lower than that of free Dox due to the gradual drug release nature. Compared to mPEG‐b‐PAMAM‐Dox_m, Gal‐PEG‐b‐PAMAM‐Dox_n showed rather high cytotoxicity against Bel‐7402, suggestive of its galactose receptor‐mediated enhanced tumor uptake. This galactose receptor‐mediated liver‐targeted profile was further confirmed by the prolonged retention time in hepatoma tissue monitored using magnetic resonance imaging. Gal‐PEG‐b‐PAMAM‐Dox_n showed better in vivo antitumor efficacy than free Dox, suggesting its great potential as a polymeric antitumor prodrug. Copyright © 2010 Society of Chemical Industry     

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.     

Poly(amidoamine), polypropylenimine, and related dendrimers and dendrons possessing different 1 → 2 branching motifs: An overview of the divergent procedures

This review presents an overview of 1 → 2 branched dendrimers and dendrons, created by a divergent procedure, from their synthesis to modern day applications. The first members of this branched class of fractal macromolecules were prepared through a cascade synthesis, which was later replaced by the iterative divergent synthetic approach. Most classes of this 1 → 2 N-, Aryl-, C-, Si-, and P-branched families are included and catalogued by their mode of connectivity. Dendritic macromolecules have had significant impact in the field of material sciences and are one of the major starting points for nanotechnology as a result of the numerous modifications that can be conducted, either on the surface or within their molecular infrastructure, thus taking advantage of their unimolecular micelle properties. These host cavities, maintained by the dendritic branches, allow for the incorporation of nanoparticles as well as metal particles, which make these attractive in catalysis and imaging studies. The solubility of these fractal constructs can be tailored depending on their surface modifications. Highly water-soluble, neutral dendrimers appended with, grown from, or acting as hosts to specific molecules give rise to a wide variety of biomedical applications such as drug delivery systems and MRI imaging agents. The inherent supramolecular or supramacromolecular chemistry has been exploited but the design and construction of uniquely tailored macrostructures have just begun. Laser dyes, as well as electron and energy donor and acceptor functionality, have also been paired with these fractal constructs in order to probe their uses in the field of molecular electronics. With their synthetic control, seemingly limitless modifications and wide variety of potential applications, as well as their now commercial availability, these 1 → 2 branched dendrimers have become an important nanostructured tools for diverse utilitarian applications. This review mainly covers 1 → 2 branched non-chiral dendrimers prepared by a divergent process but selected chiral surfaces are considered as well as metal encapsulation and a few hyperbranched routes to related imperfect dendrimers.     

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.     

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…     

PAMAM树形分子与亚甲基蓝相互作用的研究

采用分光光度法研究了以羧酸钠为端基的PAMAM树形分子与亚甲基蓝的相互作用.实验发现,树形分子的加入能明显增强亚甲基蓝分子的聚集.随树形分子代数的增加,树形分子对亚甲基蓝分子的聚集能力不断增强,这种增强作用来源于树形分子的体积增大以及分子质量增加.利用测得的数据,对树形分子对亚甲基蓝二聚常数的影响进行了定量的估算.     

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.