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Methods for characterising cyclic polymers are illustrated by reference first to dilute solution methods for cyclic poly(dimethylsiloxane) (PDMS) and then to the entrapment of cyclic polymers in networks. Preparative routes to cyclic polymers are then reviewed, including ring-chain equilibration reactions, coupling and condensation reactions and new methods using polymer-supported reagents. Some of the properties of cyclic PDMS are discussed, including differences between ring and chain polymer properties such as their melt viscosities and glass transition temperatures. Methods for preparing the first polymeric catenanes are described, using polymer-supported reagents. Future directions for cyclic polymer chemistry are indicated, including topological polymer chemistry. 相似文献
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Surface dilational moduli of polymer monolayers, blended polymer monolayers, and polymer particle monolayers spread at air–water interfaces are reviewed, focusing on measurements using surface pressure isotherm, surface pressure relaxation, and oscillating barrier methods. Differences between the surface dilational moduli of condensed polymer monolayers and expanded polymer monolayers are explored. Moreover, the features of the surface dilational moduli in blended polymer monolayers are discussed in terms of their miscibility. 相似文献
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V. Stannett 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):1177-1191
In recent years more attention has been given to the preparation and characterization of graft copolymers and an examination of their properties than to developing novel methods of synthesis. In particular, these property studies can be used to develop applications of graft copolymers. The methods used to prepare and characterize better defined grafts are briefly reviewed. The structure of most graft copolymers is such that considerable amounts of one polymer can be grafted to another without affecting greatly the main properties of that polymer. In this way, the properties of one polymer such as higher water absorption can be imparted to another without changing the mechanical properties, for example, of the second polymer. Some other inherent properties of graft copolymers are discussed, including their compatibility with the parent homopolymers, their possible con-formational changes, and other features. Finally, the use of the special nature of graft copolymers for the modification of the barrier properties of film and membranes is discussed as one possible general field of application. 相似文献
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综述了CO2在高分子合成中的研究现状,介绍了以CO2为原料合成高分子的经典方法和新型等离子体聚合法,在此基础上对CO2在高分子材料领域中的应用作了展望。 相似文献
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L. V. Vinogradova 《Russian Chemical Bulletin》2012,61(5):907-925
The anionic methods for the synthesis of homo- and heteroarm (hybrid) star-shaped polymers using fullerene C60 aPre considered. The possibilities of fullerene C60 as an agent of combination of living polymer chains and the procedures of transformation of polymer derivatives of C60 (hexaadducts) into polyfunctional macroinitiators of anionic polymerization of vinyl monomers are shown. The methods for functionalization of polymer fullerene derivatives and their combinations into structures of complex controlled architecture are presented. The structural features and initiating properties of the living polymer fullerene derivatives and their role in the formation of heteroarm star-shaped macromolecules with the controlled number of branches and predetermined molecular weight characteristics of the arms are discussed. The hydrodynamic properties of the star-shaped fullerene-containing polymers are considered. The data on the small-angle neutron scattering study of self-organization of the stars in solutions are presented. 相似文献
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Saunders BR 《Journal of colloid and interface science》2012,369(1):1-15
Hybrid polymer/nanoparticle solar cells have a light harvesting layer composed of semiconducting inorganic nanoparticles and a semiconducting conjugated polymer. They have potential to give high power conversion efficiencies (PCE). However, the PCE values reported for these solar cells are not currently as high as anticipated. This article reviews the main methods currently used for preparing hybrid polymer/nanoparticle solar cells from the colloid perspective. PCE data for the period of 2005-2011 are presented for hybrid polymer/nanoparticle solar cells and compared to those from polymer/fullerene cells. The key reasons for the relatively low PCE values for hybrid polymer/nanoparticle solar cells are uncontrolled aggregation and residual insulating ligands at the nanoparticle surface. Two hybrid polymer/nanoparticle systems studied at Manchester are considered in which the onset of aggregation and its affect on composite film morphology were studied from the colloidal perspective. It is concluded that step-change approaches are required to increase the PCEs of hybrid polymer/nanoparticle solar cells and move them toward the 10% value required for widespread commercialisation. A range of nanoparticles that have potential for application in possible longer term terawatt solar energy production are discussed. 相似文献
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Xi Mao Mian Wang Shaohong Jin Jingyi Rao Renhua Deng Jintao Zhu 《Journal of polymer science. Part A, Polymer chemistry》2022,60(11):1653-1669
Polymer particles are key materials in various biomedical applications, including drug delivery, cellular immunity, cell capture, biochip, etc. Droplets produced by microfluidics have been widely applied as templates for the fabrication of polymer particles with controllable sizes and narrow size distributions. Compared to smooth polymer particles, those with surface microstructures (e.g., tentacles, bubbles, wrinkles and pits) are more attractive due to their increased surface area and biomimetic structural characteristics. In this review, we summarized representative methods for the preparation of monodispersed polymer particles with various surface microstructures based on droplet microfluidics, as well as their typical bioapplications in drug delivery, cellular immunity and cell capture. Finally, the current challenges and further development in this research area are discussed. 相似文献
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P. W. O. Wijga 《Fresenius' Journal of Analytical Chemistry》1964,205(1):342-357
Summary The aims of analysis in polymer research are a) to obtain accurate data on the composition of a polymer sample with respect to non-polymer constituents and b) to obtain information on structure and composition of the polymer molecules themselves.Analytical methods directed towards the first aim are discussed only briefly. The emphasis is on the discussion of the more specialized techniques for the analysis of the polymer molecules themselves and a number of these methods are discussed more fully.These methods comprise methods for the determination of molecular weight (ebulliometry, osmometry, viscometry, light scattering, sedimentation) and molecular weight distribution (fractionation, turbidimetry). Information on structural details of polymer molecules can be obtained by spectroscopic techniques and from one of the newer techniques in this field: the analysis of products of pyrolytic decomposition.
Zusammenfassung Analytische Methoden finden bei der Erforschung von Polymeren Anwendung, um die genaue Zusammensetzung einer Probe in bezug auf nichtpolymere Bestandteile zu erfahren und um die Struktur und Zusammensetzung des Polymerenmoleküls selbst aufzuklären. Die dem erstgenannten Zweck dienenden Verfahren werden nur kurz diskutiert, während die Methoden, die zur Untersuchung des Moleküls selbst benutzt werden, eingehender besprochen werden. Sie umfassen Methoden zur Molekulargewichtsbestimmung (ebullioskopisches Verfahren, Osmometrie, Viscosimetrie, Lichtstreuungsmethode, Sedimentationsmessung) sowie solche zur Bestimmung der Molekulargewichtsverteilung (Fraktionierung, Trübungsmessung). Einzelheiten der Molekülstruktur können durch spektralanalytische Verfahren aufgeklärt werden oder auch mit Hilfe der Analyse der Pyrolyse-Zersetzungsprodukte, einer auf diesem Gebiet noch neueren Methode.相似文献
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Mass spectrometry (MS)-based studies of synthetic polymers often characterise detected polymer components using mass data alone. However when mass-based characterisations are ambiguous, tandem MS (MS/MS) offers a means by which additional analytical information may be collected. This review provides a synopsis of two particularly promising methods of dissociating polymer ions during MS/MS: electron-capture and electron-transfer dissociation (ECD and ETD, respectively). The article opens with a summary of the basic characteristics and operating principles of ECD and ETD, and relates these techniques to other methods of dissociating gas-phase ions, such as collision-induced dissociation (CID). Insights into ECD- and ETD-based MS/MS, gained from studies into proteins and peptides, are then discussed in relation to polymer chemistry. Finally, ECD- and ETD-based studies into various classes of polymer are summarised; for each polymer class, ECD- and ETD-derived data are compared to CID-derived data. These discussions identify ECD and ETD as powerful means by which unique and diagnostically useful polymer ion fragmentation data may be generated, and techniques worthy of increased utilisation by the polymer chemistry community. 相似文献
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V. Novikov A. Zaichenko N. Mitina O. Shevchuk K. Rayevska V. Lobaz V. Lubenets Yu. Lastukhin 《Macromolecular Symposia》2004,210(1):193-202
Main experimental approaches for obtaining polymer, inorganic and hybrid colloidal particles as well as the tailored functionalization of their surface by oligoperoxide surfactants (OPS) and metal complexes (OMC) on their basis are discussed in the paper. The methods proposed enable to combine the stage of the formation of colloidal polymer, siliceous, metal and metal-oxide particles with the stage of their surface modification by functional surface-active oligoperoxides, which are sorbed irreversibly. Novel functional particles are studied by chemical, colloidal-chemical, rheological methods and scanning electronic microscopy. The occurrence of metal and metal oxide particle formation in distinct zones correlates well with the particle size distribution. The availability of reactive ditertiary peroxidic fragments on the particle surface as a result of OPS or OMC sorption causes their reliable protection, hydrophobity and ability to form free radicals and participate in elementary stages of radical processes. 相似文献
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In the present work, the relation between the pre-exponential factor and the apparent activation energy of diffusion, ln D(0) = alpha + betaE(D), so-called compensation effect, is re-examined and critically discussed for diffusion of gases in rubbery and glassy polymers. In principle, the above equation could be derived from the enthalpy-entropy compensation in the framework of the transition state theory. However, one should consider the influence of the jump length term contained in the pre-exponential factor, which may be affected by permeating species and polymer properties. We found that parameter alpha depends on penetrant size and polymer properties, such as local chain mobility and free volume. This can be interpreted by the fact that the jump length is affected by both penetrant and polymer properties. Finally, methods for estimating the jump length are discussed. 相似文献
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回顾了高分子合成化学方法和高分子材料的发展历史,结合高分子化学的研究现状,展望了21世纪的高分子化学的发展前景。 相似文献
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Electrochemical methods for the detection of amino acids, peptides, and proteins in a variety of media are reviewed. Label-free strategies in which the detection is based on the inherent electrochemical properties of the analyte are discussed. Various processes such as direct or mediated (in solution or immobilised) redox processes and interfacial ion transfers have been employed for the electrochemical detection and determination of the target analytes. The various methods covered encompass voltammetry at uncoated and modified electrodes and at immiscible liquid-liquid interfaces, potentiometry at polymer membrane electrodes and electrochemical impedance spectroscopy. The determination of the target analytes in complex biological matrices is discussed. The various approaches highlighted here illustrate the rich capabilities of electrochemical methods as simple, low-cost, sensitive tools for the determination of these important biological analytes at trace and ultra-trace levels. 相似文献