环糊精加速疏水缔合聚合物溶解机理研究

利用环糊精(CD)对疏水基团的包合作用,在疏水缔合聚合物溶解过程中向溶剂中加入环糊精,加快疏水缔合聚合物的溶解速度。当环糊精与疏水基团摩尔比(CD∶[H])≤1,随CD∶[H]增大,溶解时间大幅下降。当CD∶[H]=10时,缔合聚合物的溶解时间缩短至与聚丙烯酰胺相当。流变学结果证明,环糊精通过包合作用破坏疏水基团的缔合结构,大幅缩短缔合聚合物解缠结时间来加速疏水缔合聚合物的溶解速度。     

基于环糊精的纳米功能组装体的研究进展

通过分子自组装形成稳定和结构可控的材料是现在功能材料学、生物学的焦点,构筑纳米尺寸的功能性分子自组装体更是接近生命现象和过程的本质。基于环糊精的超分子组装以其选择性、可调控性和生物相容性等优势引起了广泛关注。本文就近十年来基于环糊精的纳米尺寸的功能组装体的研究进展进行简要综述,包括修饰环糊精的软连接自组装,环糊精轮烷、聚轮烷、纳米线、纳米管、纳米笼的设计、构筑及其更高级组装,以及环糊精与纳米粒子的分子组装和基于环糊精的分子机器。     

第二代超分子主体化合物环糊精化学研究的新进展

简要介绍了环糊精化学的产生、发展及应用,重点介绍了:(1)环糊精衍生物的自组装、包合及应用;(2)新型环糊精超分子聚集体的形成及应用;(3)环糊精的包合作用在医药学研究中的应用。并对环糊精化学的发展进行了展望。     

环糊精的超分子组装及应用新进展

简要介绍了环糊精的结构特征及用途,详细综述了环糊精的超分子组装及纳米超分子的构筑;环糊精空腔的超分子识别功能;新型环糊精衍生物的合成及在分析化学中的应用。     

环糊精用于测定疏水缔合聚合物特性黏数

利用环糊精疏水空腔对疏水基团的包合作用,用毛细管法测定了疏水缔合聚合物在不同物质的量之比的环糊精/疏水基团〔n(CD)∶n[H]〕溶液中的特性黏数,通过一点法和外推法计算了聚合物的特性黏数。两种方法计算得到的结果相互吻合,分别为1 027.2 m L/g和1 028.3 m L/g。随n(CD)∶n[H]的增大,疏水缔合聚合物的特性黏数先增加后稳定;Huggins参数先降低后逐渐平稳。结果表明,环糊精通过对疏水基团的包合作用改变了疏水缔合聚合物的特性黏数,过量的环糊精对聚合物的特性黏数没有明显的影响。     

环糊精单分子或多分子层膜的制备及应用

环糊精因为其独特的包结和识别性能一直受到极大的关注,将环糊精固定在固体基底表面有利于更好地实现其包结选择性,发挥环糊精的潜在应用性能.本文重点综述了在金、硅及聚合物等固体基底表面组装与制备环糊精单分子或多分子层的方法和机理研究进展,主要包括:Langmuir-Blodgett法,Layer-by-Layer法,化学吸附等方法,并对这些方法进行了评价,比较了其优缺点,简要介绍了这些环糊精分子层的应用状况,且对形成单分子或多分子层膜的作用力进行了详细分析.最后围绕膜从制备到应用方面,对环糊精单分子层或多分子层膜的发展趋势进行了展望,认为对常规方法作出改进及采用更加简单有效的新方法制备性能更加稳定的取向性环糊精单/多分子层膜是未来的重点研究方向.     

氢键驱动大分子自组装研究进展

大分子自组装是构筑纳米材料新型便捷的重要方法之一。氢键驱动大分子自组装避免了嵌段共聚物的复杂的合成过程,扩大了组装单体的选择范围,而且可以进一步得到空心球等结构。文章从三个方面分别介绍氢键驱动大分子自组装组装方法及国内外最新研究成果。     

β-环糊精/四氧化三铁纳米复合材料功能化研究进展

四氧化三铁纳米粒子具有顺磁性、高比表面积和能锚定和吸附功能分子的活跃表面等性质,在诸多领域显示了广泛的应用价值。将环糊精修饰在纳米四氧化三铁上,构筑成为β-环糊精/四氧化三铁纳米复合材料,既充分发挥环糊精在主客体催化、药物负载和缓释、有机污染物的包合作用,又能巧妙利用了纳米四氧化三铁比表面积大,单分散性和磁性响应可回收的优势。文章综述了β-环糊精/四氧化三铁纳米复合材料在环境污染物吸附/相分离、催化、药物载体等方面的研究进展。     

β-环糊精/氯菊酯包合物制备工艺优化

文章采用超声波法制备了β-环糊精/氯菊酯超分子包合物。采用正交设计研究氯菊酯与β-环糊精的主客体摩尔比、包合温度和包合时间等对包合作用的影响,优选出超声波法制备了β-环糊精/氯菊酯超分子包合物的最佳工艺条件。借助紫外光谱、红外光谱、差热分析证明了超分子包合物的形成。     

基于AB型环糊精主客体相互作用的超分子聚合物的研究进展

对环糊精的羟基进行选择性衍生化,可以调节环糊精分子与客体分子的络合特性。文章综述了各类基于环糊精主客体相互作用的的组装单体,通过自组装可以形成不同拓扑结构的超分子聚合物组装体。     

Complex macromolecular architecture design via cyclodextrin host/guest complexes

The design of complex macromolecular architectures has driven macromolecular engineering over the past decades. The introduction of supramolecular chemistry into polymer chemistry provides novel opportunities for the generation of macromolecular architecture with specific functions. Cyclodextrins are attractive design elements as they form supramolecular inclusion complexes with hydrophobic guest molecules in aqueous solution affording the possibility to combine a large variety of building blocks to form novel macromolecular architectures. In the present critical review, the design of a broad range of macromolecular architectures driven by cyclodextrin host/guest chemistry is discussed, including supramolecular block copolymers, polymer brushes, star and branched polymers.     

Hierarchy analysis of different cross-linkers used for the preparation of cross-linked cyclodextrin as drug nanocarriers

This paper describes the hierarchical analysis performed on various cross-linking agents used for the preparation of cyclodextrin nanosponges, as a drug carrier for poorly soluble and unstable drugs. Prioritizing the right one is crucial for research considering the factors like time, cost materials, and simplicity of the process. A four-level hierarchy model was constructed for four different cross-linker types, namely, carbonyl, diisocyanate, anhydride, and epichlorohydrin based on different criteria and subcriteria involved in the preparation of cyclodextrin polymer. It applies the principle of pairwise comparison, priority vector generation, and synthesis. It restricts reprocessing due to inapplicable decisions. This methodology helped in prioritizing carbonyl cross-linkers with regard to simple and easy processing steps with minimum input materials and desirable physicochemical characteristics for nanosponges with the priority value of 32.4%. The cross-linker was prioritized with a minimum judgment error by consistency verification. This analysis helps minimize experiments, development process, and improved product quality of cross-linked cyclodextrin as a drug delivering carrier.     

Ultrasonic monitoring of the network formation in superabsorbent cellulose based hydrogels

Biodegradable hydrogels are finding increasing interest in the academic and industrial field due to their high swelling capacity and the potential for many novel applications enabled by their biodegradability. The monitoring of the hydrogel cross-linking process is a crucial step for predicting hydrogel performances in terms of degree of swelling and viscoelastic properties.In this work, the chemical cross-linking of cellulose based hydrogels has been monitored during synthesis in water by means of ultrasonic wave propagation and low frequency dynamic mechanical analysis (DMA). The effect of the cross-linker concentration on the hydrogel acoustic behaviour has been also analysed and correlated with the different elastic response developed by the macromolecular hydrogel.The results demonstrate the reliability of the ultrasonic wave propagation in the following network formation process of a superabsorbent hydrogel, being capable of following the limited changes in the physical properties of the reacting solution.     

煤的大分子结构与超细物理结构研究(Ⅰ)煤的大分子结构

本文评述了关于煤大分子结构研究的一些重要文献,煤组成结构研究的发展过程;讨论了在煤炭科学中有重要影响的煤大分子“三维结构基质”、“三维交联结构网络”、“大分子相与分子相”和“自相关多体结构”模型。对煤大分子的组成结构进行了深入认识。     

Multiacrylated Cyclodextrin: A Bio‐Derived Photocurable Macromer for VAT 3D Printing

A novel cyclodextrin‐derived multiacrylated macromer (Ac‐γ‐CD) is successfully prepared and tested for the generation of highly crosslinked materials by means of UV‐curing. The high photoreactivity of the macromer under UV‐light irradiation is confirmed by means of real‐time photorheology. Moreover, dynamic mechanical thermal analyses proved that the properties of the thermosetting networks can be easily tailored by varying the concentration of the macromer in the precursor formulation. Finally, different Ac‐γ‐CD‐based formulations are successfully used as innovative inks to reproduce several computer‐aided design files by digital light processing 3D printing.     

丙烯酸树脂皮革涂饰中室温自交联体系的现状与研究

丙烯酸树脂在皮革涂膜过程中实现大分子链室温交联而形成网络结构是目前普遍采用的技术思路和方法,这种自交联体系的方式与机制也是目前丙烯酸树脂乳液制备研究领域的热点之一。本文综述了皮革用丙烯酸树脂室温交联体系的技术发展与应用现状,重点介绍了目前丙烯酸树脂皮革涂饰中几种新型室温交联体系研究进展。     

反应挤出法制备高熔体强度聚丙烯的研究

采用不饱和硅烷为接枝单体,不饱和烯烃为交联助剂,在双螺杆挤出机上一步法实现了均聚型聚丙烯(PP)的接枝交联,制得了高熔体强度PP。结果表明,接枝单体、交联助剂、引发剂均显著地影响PP的熔体流动性能。在硅烷和交联助剂共存的条件下,PP的熔体流动性能随引发剂过氧化苯甲酰(BPO)用量的增加而下降。交联助剂起到稳定大分子自由基的作用,增加了硅烷的接枝效率和接枝速率;并指出硅烷接枝交联法是目前制备高熔体强度PP方法中最有希望实现工业化生产的技术。     

Kinetic modeling of the peroxide cross-linking of polymers: From a theoretical model framework to its application for a complex polymer system

Peroxides react with polymers in a variety of ways. The fundamental comprehension and prediction of pertinent kinetics of reactions is consequently indispensable. Based on the mechanisms of reactions of cross-linking process, a new theoretical kinetic model framework was developed. The kinetic model was then applied to the reactions of cross-linking process of various peroxides and a chosen complex polymer compound, namely partially hydrogenated poly(acrylonitrile-co-1,3-butadiene). Whereas the initial macromolecular backbone structure was determined utilizing attached proton test carbon nuclear magnetic resonance, the evolution of overall concentration of cross-links was monitored through viscoelastic characteristics of the system. The model demonstrated good agreement with experimentally measured data and, moreover; the evolution of concentrations of various crucial species inherent to the cross-linking process were predicted. The most significant advantage of the developed kinetic model is that it may be readily applied to an assortment of polymer/peroxide systems.     

丙烯酸树脂皮革涂饰中室温交联体系的研究进展

丙烯酸树脂在皮革涂膜过程中实现大分子链室温交联而形成网络结构是目前普遍采用的技术和方法,该交联方法与机理也是目前丙烯酸树脂乳液制备研究领域的热点之一。该文综述了皮革用丙烯酸树脂室温交联体系的技术发展与应用现状,重点介绍了目前丙烯酸树脂皮革涂饰中几种新型室温交联体系的研究进展。     

Trisodium trimetaphosphate crosslinked xanthan networks: synthesis,swelling, loading and releasing behaviour

Xanthan (Xan) is a biocompatible and biodegradable polysaccharide with a promising potential as substrate for controlled drug delivery applications. Xan based hydrogels were synthesized in alkaline medium using trisodium trimetaphosphate (STMP) as crosslinking agent. Hydrogels with various crosslinking agent/polymer ratios were synthesized and subsequently characterized by the means of elemental analysis and dynamic swelling degree, model compound loading and releasing behaviour. Two physical parameters (crosslinking density and phosphate charge) are manifesting antagonistic actions by stiffening or disrupting the three-dimensional macromolecular ensemble. The highest swelling degree was obtained using an intermediate STMP:Xan ratio in which case the opposing effects of the two forces are well balanced. The synthesized networks are pH sensitive. In acid and alkaline media the swelling degrees are lower by comparison to neutral pH. The entrapping and releasing behaviour of the newly synthesized xanthan networks were studied using methylene blue as a cationic model molecule. The releasing kinetics present a first-order model.