支化结构对树枝状聚合物溶液剪切前后流变性能的影响

采用吴茵混调器模拟聚合物在其配制、输送、注入中的机械剪切作用，研究了不同支化程度对剪切前后的驱油用树枝状聚合物溶液的流变性能的影响。首先制备了3种不同支化程度的树枝状聚合物，研究了剪切前后的树枝状聚合物的分子链粒径分布和分子量大小，然后研究了不同因素对树枝状聚合物流变性能的影响并考察了树枝状聚合物溶液的黏弹性能，最后结合环境扫描电镜分析支化结构对剪切前后树枝状聚合物溶液的流变性能的影响。结果表明：支化程度高的树枝状聚合物具有更大的流体力学半径和分子量，受环境影响较小；树枝状聚合物溶液呈现假塑性流体特征，支化程度越高，剪切前后的聚合物溶液幂律指数n越小、稠度系数K越大；支化程度高的树枝状聚合物溶液支链间越容易发生缠结，形成致密、多层的空间网状结构，致使剪切前后的聚合物溶液的流变性能越好。     

树枝状-星型聚合物的合成研究进展

介绍了树枝状-星型聚合物的合成方法,重点综述了以树枝状大分子引发剂合成树枝状-星型聚合物的研究进展,对树枝状-星型聚合物的性质和应用等进行了讨论.     

树枝状聚合物的合成及其在油田化学中的应用

树枝状聚合物由于其独特的结构特点而具有特殊的性能,在众多领域有着潜在的应用价值。综述了近年来树枝状聚合物的合成及其在油田化学中的研究进展,介绍了树枝状聚合物在破乳剂、絮凝剂、蒙脱土插层剂、黏土稳定剂、驱油剂等方面的应用,旨在为新型的油田化学剂的开发提供新的设计思路和方法。最后,对树枝状聚合物在油田化学领域中的应用前景进行了展望。     

树枝状聚合物的合成在油田化学中的应用

随着我国石油产业的快速发展,对于油田化学的研究也在逐步展开,并且取得了一些突破性的进展,而其中树枝状聚合物在油田化学的作用和价值显得尤为关键。由于树枝状聚合物本身特有的成分构造和特性,使其在很多相关方面具有重要的实用价值。本文从目前的树枝状聚合物的合成在油田化学中的研究进程入手,分析了树枝状聚合物在其他方面例如紫凝剂以及破乳剂等方面的应用,为油田化学剂的创新研发提供经验,同时展望树枝状聚合物的合成在油气化学中应用的发展前景。     

树枝状聚合物的化学性质和在反渗透阻垢上的应用

树枝状聚合物是一种高度分叉的具有三维立体构造的高分子,虽然在自然界里树枝状聚合物很常见,但其工业应用却是刚刚开始.作者首先介绍了由于其独特的几何构造和化学特征,树枝状聚合物在反渗透水处理中所表现出的巨大的工业应用优势,进而重点介绍了相比于直链型聚合物,基于树枝状聚合物的阻垢剂可以更加高效地控制反渗透原水中的无机盐垢、胶体和有机物.最后得出结论,树枝状聚合物的独特性能可以提供给用户更加全面的反渗透系统给水控制,降低膜的污染倾向并减少膜的清洗需求.     

树枝状聚合物的合成和应用

树枝状聚合物具有高度支化的结构和独特的单分散性,使这类聚合物具有特殊的性质和功能,在生物医药、材料改性、工业催化、石油工业等领域有着良好的应用前景。介绍了树枝状聚合物的结构特点、合成方法及应用。     

阳离子树枝状聚合物与铁锈层的相互作用

探讨树枝状聚合物与固体物质的相互作用对涉及到它们的涂覆、絮凝、沉淀等工艺过程有很重要的意义。研究了pH、离子强度和树枝状聚合物的代数对阳离子PAMAM树枝状聚合物在铁锈／水界面吸附时的影响，试验采用G3和G7两种代数的PAMAM树枝聚合物。结果表明，在pH为9时，     

美国开发制备金属氧化物纳米粒子技术

美国密歇根中部大学研究人员首次开发了采用树枝状聚合物支架制备金属氧化物纳米粒子的技术。树枝状聚合物以前用于制备金属纳米粒子，而金属氧化物纳米粒子广泛应用于传感器、催化剂和微电子等领域。在制备SnO2纳米粒子时，研究者将锡酸纳与第四代聚胺基酰胺或聚丙烯亚胺树枝状聚合物相混合，     

模型聚合物的制备

本文对模型聚合物（包括线型均聚物以及远螯聚合物、嵌段聚合物、环状聚合物、树枝状聚合物等特征结构的聚合物）的制备方法进行综述,并着重讨论了活性聚合在模型聚合物制备中的应用     

原子转移自由基聚合在树形聚合物合成中的应用

原子转移自由基聚合(ATRP)技术是一种新型的可控/活性聚合技术,可有效地对聚合物的分子结构进行设计,制备出各种不同性能、不同组成、不同功能化的结构确定的聚合物。综述了利用ATRP技术合成树枝状-线性嵌段共聚物、类树枝状聚合物(dendrimer-like polymer)、具有刺激-响应性末端基团的树枝状聚合物、树枝状-星型嵌段共聚物和基于树枝状聚合物的聚合物刷的研究进展。     

Interaction of Cationic Carbosilane Dendrimers and Their siRNA Complexes with MCF-7 Cells

The application of siRNA in gene therapy is mainly limited because of the problems with its transport into cells. Utilization of cationic dendrimers as siRNA carriers seems to be a promising solution in overcoming these issues, due to their positive charge and ability to penetrate cell membranes. The following two types of carbosilane dendrimers were examined: CBD-1 and CBD-2. Dendrimers were complexed with pro-apoptotic siRNA (Mcl-1 and Bcl-2) and the complexes were characterized by measuring their zeta potential, circular dichroism and fluorescence of ethidium bromide associated with dendrimers. CBD-2/siRNA complexes were also examined by agarose gel electrophoresis. Both dendrimers form complexes with siRNA. Moreover, the cellular uptake and influence on the cell viability of the dendrimers and dendriplexes were evaluated using microscopic methods and XTT assay on MCF-7 cells. Microscopy showed that both dendrimers can transport siRNA into cells; however, a cytotoxicity assay showed differences in the toxicity of these dendrimers.     

Perylenediimide-cored dendrimers and their bioimaging and gene delivery applications

In the past few years, perylenediimide-cored (PDI-cored) dendrimers have been successfully prepared and applied in various fields. In this review, we focus on the structural design and synthesis strategies of PDI-cored dendrimers that involve convergent and divergent synthesis approaches. When building the outer shell of PDI-cored dendrimers, first hydrophobic and then hydrophilic macromolecules are introduced. The advantages of water-soluble PDI-cored dendrimers include strong red fluorescence, excellent photostability, low cytotoxicity, high quantum yield, and versatile surface modification. The biological application of water-soluble PDI-cored dendrimers is broad, including fluorescence live-cell imaging, fluorescent labeling, and gene delivery, owing to the rapid development of these materials in the past decade. The challenges and outlooks in this field will also be discussed.     

树枝状大分子聚酰胺胺对布洛芬的增溶性能研究

采用发散合成法,合成了系列以乙二胺为核的树枝状大分子聚酰胺 胺(PAMAM)和三羟基氨基甲烷改性的聚酰胺 胺,用紫外 可见分光光度计测定了树枝状大分子对布洛芬的增溶能力。结果表明:两类树枝状大分子对布洛芬的增溶量均高于传统的表面活性剂SDS,而且增溶能力均随代数的增加而增加;在引入羟基后,PAMAM增溶能力明显提高,作为一种新型的药物输送剂,显示了良好的应用前景。     

Molar Mass Characterization and Solution Behaviour of Poly(ether amide) Dendrimers

Summary Poly(ether amide) dendrimers with different molar masses were investigated using Size Exclusion Chromatography (SEC) with linear standard calibration and Matrix Assisted Laser Desorption/Ionization – Time-of-Flight – Mass Spectroscopy (MALDI-TOF-MS). The SEC behaviour of the dendrimers was investigated in different column systems, in pure and in mixed N,N-dimethylacetamide with water and LiCl. This behaviour was compared to linear poly(styrene) and poly(2-vinyl pyridine) standards. Kuhn-Mark-Houwink-Sakurada relationship yielded evidence about the molecular shapes of the polymers in solution and explained the different solution behaviour of the polymers. The universal calibration method was tested for its application to molar mass determination of poly(ether amide) dendrimers.     

Demulsification of Crude Oil Emulsion Using Polyamidoamine Dendrimers

Abstract

Six dendrimers with the same polyamidoamine (PAMAM) basic structure but different terminals/generations were synthesized by divergent method. The dendrimers were studied by surface tension measurement at the air‐water interface. The demulsification performance for oil/water (O/W) simulated crude oil emulsion and crude oil extract directly from field was investigated. The experimental results indicate that the three dendrimers terminated with ester groups were insufficient demulsifiers for crude oil emulsion. However, the three dendrimers terminated with amine groups exhibited excellent demulsification performance for O/W emulsions. As demulisifers, amine based dendrimers were superior to the commercial polyether ones (SP‐169 and BP‐169). The possible mechanisms for the nanocontainer effects of the dendrimers, through either surface adsorption or internal encapsulation, were discussed.     

树状大分子的手性构建

综述了手性基团的树状大分子中的构建,并对此类化合物的性质及研究和应用前景作了简要介绍。     

Investigation of allyl‐capped carbosilane dendrimers used as crosslinker for silicone rubber

High‐temperature vulcanized silicone rubber was prepared by using allyl‐capped carbosilane dendrimers, in which the core molecules were Si(CH₂CH?CH₂)₄ and Ph₂Si(CH₂CH?CH₂)₂ as crosslinker and nanoscale reinforcing filler, respectively. Allyl‐capped carbosilane dendrimers improved the mechanical properties of silicone rubber. The optimum tensile strength and tear strength were 9.6 MPa and 31.0 kN/m, respectively, when using SiG_n(allyl)m as the crosslinker and 10.1 MPa and 32.0 kN/m, respectively, when using Ph₂SiG_n(allyl)m as the crosslinker. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1772–1775, 2006     

异氰酸酯型树枝状大分子的合成及应用

树枝状大分子在化学、生物医学、环境保护等领域应用广泛,是近年来发展迅速的一类新型材料。介绍了树枝状大分子的研究进展、结构性能、合成方法及其应用,论述了以异氰酸酯化合物为新型单体的树枝状大分子的合成。     

Gelatin hydrogels with PAMAM nanostructured surface and high density surface-localized amino groups

Amino-terminated PAMAM dendrimers with 16 and respectively 64 amino groups have been chemically immobilized onto the surface of glutaraldehyde (abbreviated GA) crosslinked thin gelatin scaffolds based on Schiff-base linkage formation between the amines and free aldehyde from partially unreacted GA. Crosslinking and dendrimers surface modification of hydrogels have been chemically and physically investigated using FT-IR spectroscopy and microscopy, UV–VIS, LM, AFM, swelling tests and a colorimetric technique. Two types of gelatin-based hydrogels with homogeneous nanorough surfaces and presenting an increased number of amino groups available for further chemical reactions have been obtained. The synthesis strategy presented in this work seems to open a new route for nanorough crosslinked gelatin scaffolds that could be further used for biomedical and especially for hard tissue engineering application.     

Synthesis and properties of novel perylenebisimide-cored dendrimers

A group of perylenebisimide-cored dendrimers with polyphenylene dendrons at four bay positions were synthesized and characterized. The electron-deficient pentafluorophenyl or cyano groups were grafted at the dendrimer surface with the aim to further increase the n-type features of the resulted dendrimers. The electrochemical and optical properties were investigated. All the dendrimers show good solubility and film-forming properties, high EA values of 3.8-3.9 eV, and high fluorescent quantum yields. All these merits indicate that they are potential multifunctional materials for application in optoelectronic devices such as solar cells or organic light-emitting devices.