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101.
Carlo Durrer Juan Manuel Irache Dominique Duchene Gilles Ponchel 《Journal of colloid and interface science》1995,170(2)
The interactions of pig gastric mucin and bovine submaxillary mucin with carboxylate (PCM) and amino (PAM) polystyrene latexes with 750 and 1000 nm diameters have been studied in vitro. The mucin interaction increased when the pH decreased from 7.4 to 3.0 and when the electrolyte concentration increased from 86 to 205 mM. The driving force of the interaction was very probably nonionic. Under certain conditions, electrostatic attraction also was important for PAM. Under all experimental conditions tested, the mucins interacted less with PAM than with PCM. The functional groups of the latexes directed the conformation of the adsorbed mucins at the interface. At low pH, the mucins probably were adsorbed in multilayers. 相似文献
102.
Roberta Collino Joël Therasse Frédéric Chaput Jean-Pierre Boilot Yves Levy 《Journal of Sol-Gel Science and Technology》1996,7(1-2):81-85
In this work we investigated the biological properties of sol-gel films in aqueous medium. Functionalized silica films were prepared by the sol-gel process, from organically modified silicon alkoxides with amino or thiol groups. Covalent binding of proteins with different orientations according to the hydrophilic or hydrophobic character of the surface was studied. This binding occurred via a covalent coupling agent providing a very stable linkage. No denaturation was detected and a good detection of the antigen was observed. Immunoassays have demonstrated the biological activity of grafted antibodies. 相似文献
103.
This work deals with the displacement of end-anchored copolymers by the addition of solvent displacer. The adsorption behavior of functionalized polystyrene-block-polybutadiene diblock copolymers from dilute solution in toluene using silicon wafers as solid substrates is investigated by means of null-ellipsometry. The desorption phenomena are observed by adding displacers of low molecular weight to the mixture. The displacers used are tetrahydrofuran (THF) and acetone. The critical composition of the binary solvent mixture at which the desorption is complete, is determined experimentally. 相似文献
104.
In the present work, ruthenium nanoparticles were synthesized on functionalized reduced graphene oxide (rGO). First, the surface of rGO was modified with two para‐arsanilic acid and dithiooxamide promoters to create the rGO with scattered hydrophilic positions. The ruthenium nanoparticles were synthesized and immobilized simultaneously in small hydrophilic micro‐reactors under mild conditions. Characterization of the synthesized nanocatalyst was confirmed with different techniques, such as transmission electron microscopy (TEM), X‐ray diffraction, Fourier transform‐infrared and scanning electron microscopy. TEM images of the synthesized catalyst show the Ru nanoparticles have diameters less than 6 nm. The designed nanocatalyst was investigated for the selective liquid phase oxidation of cyclohexene with molecular oxygen in an autoclave under solvent‐free conditions, which obtained a maximum of 91% conversion and 90% selectivity under optimized conditions. The catalytic activity over rGO‐AO‐TO/Ru recycled catalyst remained at a satisfactory state after at least five runs. 相似文献
105.
The crystallization behavior of Nylon-6 and the interaction in Nylon-6/nanoclay/functionalized polyolefin blends were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. For samples without any thermal history, the interaction between Nylon-6 and nanoclay or the interaction between Nylon-6 and functionalized polyolefin favors the formation of γ form crystal. In contrast, the presence of both nanoclay and functionalized polyolefin together in Nylon-6 was found to have an antagonistic effect on each other's ability to promote the formation of γ form crystal. This was attributed to the complex interactions between the constituents. The crystallization behavior of Nylon-6 in Nylon-6/nanoclay/functionalized polyolefin blends is clearly affected by the cointeraction of these effects. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1494–1502, 2007 相似文献
106.
S. Kannan 《Catalysis Surveys from Asia》2006,10(3-4):117-137
Hydrotalcite-like (HT-like) materials have been studied extensively in the last three decades. Although these materials initially perceived as potential anion exchangers, unrelenting efforts have also been attempted to use them as catalytic materials or as catalytic supports. There are varied ways by which one can use them for catalysis viz.; 1. Use them in as-synthesized form 2. Use them after calcining where the structural integrity of layered lattice is lost 3. Use the interlayer as functional spaces with moieties of catalytic interest 4. Use them after destruction or delamination and restructuring and 5. Use them as support or matrix. In this review, we are reporting the catalytic applications of HT-like materials and their derived forms carried out in our research group for the last 15 years in these various ways, covering reactions such as nitrous oxide decomposition, selective oxidation of organic compounds of industrial relevance and base-catalyzed isomerization of chemicals of perfumery interest. Although this review primarily focuses on our work, wherever applicable, related or relevant works from other groups are also presented to bestow comprehensiveness. 相似文献
107.
A. Mercier S. Kuroki I. Ando H. Deleuze O. Mondain‐Monval 《Journal of Polymer Science.Polymer Physics》2001,39(9):956-963
The structure of laboratory‐made polyHIPEs was successfully characterized by cross‐polarity/magic‐angle spinning, solid‐state 13C NMR experiments. The signals of vinyl groups appeared in the spectrum of the polyHIPE precursor PH? CH?CH2, which was prepared by the polymerization of the divinylbenzene continuous phase from a highly concentrated reverse emulsion. This material was chemically modified by the regioselective free‐radical addition of thiols to the pendant vinyl groups. Spectra of materials modified by the grafting of C8 and C12 alkyl chains, PH? SC8 and PH? SC12, respectively, were produced. The signals of the vinyl groups disappeared in favor of methylene groups. This experiment clearly established that the alkyl chains were covalently bound to the polymer. To elucidate the dynamic aspect of long chains in polyHIPE, we measured the 13C spin–lattice relaxation times (T1) of PH? SC12 from 25 to 100 °C with variable‐temperature, solid‐state, high‐resolution 13C NMR spectroscopy, revealing a strong variation in T1 along the alkyl side chain. Furthermore, the crystallinity of a wide range of chemically modified polyHIPEs, including PH? SC12, was studied with pulse 1H NMR. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 956–963, 2001 相似文献
108.
Millimeter size γ‐Al2O3 beads were prepared by alginate assisted sol–gel method and grafting organic groups with propyl sulfonic acid and alkyl groups as functionalized γ‐Al2O3 bead catalysts for fructose dehydration to 5‐hydroxymethylfurfural (5‐HMF). Experiment results showed that the porous structure of γ‐Al2O3 beads was favorable to the loading and dispersion of active components, and had an obvious effect on the properties of the catalyst. The lower calcination temperature of γ‐Al2O3 beads increased the specific surface area, the hydrophobicity and the activity of catalysts. Competition between the reaction of alkyl groups and ‐SH groups with surface hydroxyl during the preparation process of the catalyst influenced greatly the acid site densities, hydrophobic properties and activity of the catalyst. With an increase in the alkyl group chain, the hydrophobicity of catalysts increased obviously and the activity of the catalyst was enhanced. The most hydrophobic catalyst C16‐SO3H‐γ‐Al2O3–650°C exhibited the highest yield of 5‐HMF (84%) under the following reaction conditions: reaction medium of dimethylsulfoxide/H2O (V/V, 4:1), catalyst amount of 30 mg, temperature of 110°C and reaction time of 4 hr. 相似文献
109.
Guangchen Li Prof. Dr. Michal Szostak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(3):611-615
The direct transition-metal-free acylation of amides with functionalized Grignard reagents by highly chemoselective N−C cleavage under kinetic control has been accomplished. The method offers rapid and convergent access to functionalized biaryl ketones through transient tetrahedral intermediates. The direct access to functionalized Grignard reagents by in situ halogen–magnesium exchange promoted by the versatile turbo-Grignard reagent (iPrMgCl ⋅ LiCl) permits excellent substrate scope with respect to both the amide and Grignard coupling partners. These reactions enable facile, operationally simple and chemoselective access to tetrahedral intermediates from amides under significantly milder conditions than chelation-controlled intermediates. This novel direct two-component coupling sets the stage for using amides as acylating reagents in an alternative paradigm to the metal-chelated approach, acyl metals and Weinreb amides. 相似文献
110.
Marziyeh Rohaniyan Abolghasem Davoodnia S. Ali Beyramabadi Amir Khojastehnezhad 《应用有机金属化学》2019,33(5)
New Schiff base (SB) functionalized graphene oxide (GO) nanosheets containing phosphomolybdic counter‐anion H2PMo12O40¯ (H2PMo) were successfully prepared by grafting of 3‐aminopropyltriethoxysilane (APTS) on GO nanosheets followed by condensation with benzil and finally reaction with phosphomolybdic acid (H3PMo12O40, denoted as H3PMo) and characterized using Fourier transform infrared (FT‐IR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), particle size distribution, energy‐dispersive X‐ray (EDX) analysis, EDX elemental mapping, and inductively coupled plasma optical emission spectrometry (ICP‐OES). The prepared new nanomaterial, denoted as GO‐SB‐H2PMo, was shown to be an efficient heterogeneous catalyst in one‐pot, three‐component reaction of β‐naphthol, aldehydes, and dimedone, giving high yields of tetrahydrobenzo[a]xanthene‐11‐ones within short reaction times. The catalyst is readily recovered by simple filtration and can be recycled and reused several times with no significant loss of catalytic activity. 相似文献