References of "Grandjean, Jean"
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See detailHybrid lamellar silica: Combined template extraction and hydrophilic silanation
Toussaint, Gilles ULg; Brisbois, Magali ULg; Grandjean, Jean ULg et al

in Journal of Colloid & Interface Science (2009), 329(1), 120-126

The surface modification of lamellar silica prepared by liquid crystal templating has been investigated. Two hydrophilic surface modifier agents, 2-glycidoxypropyltrimethoxysilane and 2-[methoxy ... [more ▼]

The surface modification of lamellar silica prepared by liquid crystal templating has been investigated. Two hydrophilic surface modifier agents, 2-glycidoxypropyltrimethoxysilane and 2-[methoxy(polyethyleneoxy)propyl)] trimethoxysilane, have been tested. Characterizations of the modified silica include thermal analysis, C-13 and Si-29 solid state NMR, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The different characterizations confirmed the preservation of the lamellar morphology and the Successful surface modification with both silanes along with the template elimination. The results also indicate that the structure and length of the silanes influence the final lamellar organization as well as the grafting yields and mechanisms. (C) 2008 Elsevier Inc. All rights reserved. [less ▲]

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See detailXRD and NMR characterization of synthetic hectorites and the corresponding surfactant-exchanged clays
Gertsmans, André; Urbanczyk, Laetitia ULg; Jérôme, Robert ULg et al

in Clay Minerals (2008), 43

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See detailStructural and electrical properties of tellurovanadate glasses containing Li2O
Krins, Natasha ULg; Rulmont, André ULg; Grandjean, Jean ULg et al

in Solid State Ionics (2006), 177(35-36 Sp. Iss. SI), 3147-3150

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition ... [more ▼]

Glassy materials are promising intercalation compounds, due to their open network structure and absence of grain boundaries. Some glasses containing alkali ions and a high concentration of transition metal ions can present mixed ionic-electronic conductivity and are therefore potential candidates for application as cathode material in Li-ion batteries. The present work is devoted to the ternary system xLi(2)O-(1-x)[0.3V(2)O(5)-0.7TeO(2)] with 0 <= x <= 0.4. These compounds were prepared by heat treatment in air at 800 degrees C followed by traditional quenching. Raman spectroscopy and V-51 nuclear magnetic resonance measurements were performed in order to highlight the structural short range order modifications induced by the introduction of the Li2O network modifier. These structural effects can be related to the electrical behaviour, as studied by complex impedance spectroscopy measurements. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMotional heterogeneity of intercalated species in modified clays and poly(epsilon-caprolactone)/clay nanocomposites
Urbanczyk, Laetitia ULg; Hrobarikova, Jana; Calberg, Cédric ULg et al

in Langmuir (2006), 22(10), 4818-4824

Modified laponites and synthetic saponites are used as precursors for the preparation of poly(epsilon-caprolactone) (PCL)/clay nanocomposites. The structure and dynamics of species intercalated in the ... [more ▼]

Modified laponites and synthetic saponites are used as precursors for the preparation of poly(epsilon-caprolactone) (PCL)/clay nanocomposites. The structure and dynamics of species intercalated in the modified clays and the corresponding nanocomposites are characterized by X-ray diffraction and magic-angle spinning NMR. The influence of the headgroup, the hydrocarbon chain length, and the loading of the surfactant on the nanocomposite formation are discussed. The yield of PCL intercalation is related to the probability of direct polymer-clay interactions and to the size of the clay platelets. Relaxation times in the laboratory and rotating frames that allow characterization of fast and slow molecular dynamics in these systems are discussed, showing a motional heterogeneity of the intercalated species. [less ▲]

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See detailSolid-state NMR study of modified clay and polymer/clay nanocomposites
Grandjean, Jean ULg

in Clay Minerals (2006), 41

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See detailThe step-by-step Robinson annulation of chalcone and ethyl acetoacetate - An advanced undergraduate project in organic synthesis and structural analysis
Delaude, Lionel ULg; Grandjean, Jean ULg; Noels, Alfred ULg

in Journal of Chemical Education (2006), 83(8), 1225-1228

The Robinson annulation is a three-step process involving a Michael addition followed by an internal aldol condensation and a dehydration. Under appropriate experimental conditions, it is possible to stop ... [more ▼]

The Robinson annulation is a three-step process involving a Michael addition followed by an internal aldol condensation and a dehydration. Under appropriate experimental conditions, it is possible to stop the reaction after every step and to isolate the three products separately. This feature is particularly attractive in the frame of an organic chemistry course. It allows students to confirm experimentally the validity of the stepwise mechanism and to get a more thorough understanding of the whole process. It also permits them to synthesize a rich set of related molecules that can be compared and characterized through various analytical techniques. Thus, a stoichiometric mixture of chalcone and ethyl acetoacetate was reacted in ethanol. Depending on the quantity of barium hydroxide monohydrate used as catalyst, the reaction time, and the temperature, three different products were obtained. Their full IR, 1H, 13C, COSY, NOESY, and HETCOR NMR spectra are supplied. Examination of the spectroscopic data helps uncover many challenging structural analysis problems. Among them, the diastereoselective formation of chiral centers during the annulation process, the distinction between axial and equatorial substituents on a cyclohexane ring, and the possibility of a keto-enol tautomerism are extensively discussed. [less ▲]

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See detailDiscovery of non-biodegradable fossil cellulose.
Lechien, V.; Rodriguez, Ch.; Grandjean, Jean ULg et al

Poster (2004, December 17)

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See detailSolid-state NMR study of intercalated species in poly(epsilon-caprolactone)/clay nanocomposites
Hrobarikova, J.; Robert, J. L.; Calberg, Cédric ULg et al

in Langmuir (2004), 20(22), 9828-9833

The structure and dynamics of surfactant and polymer chains in intercalated poly(epsilon-caprolactone)/clay nanocomposites are characterized by (31)P magic-angle spinning (MAS) and (13)C cross ... [more ▼]

The structure and dynamics of surfactant and polymer chains in intercalated poly(epsilon-caprolactone)/clay nanocomposites are characterized by (31)P magic-angle spinning (MAS) and (13)C cross-polarization MAS NMR techniques. To obtain hybrid materials with the low polymer content required for this study, in situ intercalative polymerization was performed by adapting a published procedure. After nanocomposite formation, the chain motion of the surfactant is enhanced in the saponite-based materials but reduced in the Laponite ones. Compared to the starting clay, the trans conformer population of the surfactant hydrocarbon chain in the nanocomposite decreases for the saponite systems. Mobility of the polymer chain is higher in the nanocomposites than in the bulk phase. The charge of the modified saponite does not significantly influence chain mobility in the nanocomposites. [less ▲]

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See detailMixed self-assembly of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers and sodium dodecyl sulfate in aqueous solution
Vangeyte, Patrick; Leyh, Bernard ULg; Auvray, L. et al

in Langmuir (2004), 20(21), 9019-9028

Interaction of amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers with anionic sodium dodecyl sulfate (SDS) has been investigated in aqueous solution. Formation of mixed micelles has ... [more ▼]

Interaction of amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers with anionic sodium dodecyl sulfate (SDS) has been investigated in aqueous solution. Formation of mixed micelles has been confirmed by surface tension measurements, whereas the influence of the surfactant on the copolymer self-assembling has been studied by measurement of the 1H NMR self-diffusion coefficients and by small-angle neutron scattering. As a rule, the surfactant decreases the heterogeneity of the micellar structures formed by the copolymer in water. Moreover, increasing the content of SDS results in the increasingly more important extension of the poly(ethylene oxide) (PEO) corona chains and the copolymer micelle deaggregation. The stability of the micelles against SDS increases with the length of the hydrophobic block. Preliminary two-dimensional NMR measurements with nuclear Overhauser enhancement have confirmed the spatial vicinity between SDS and the constitutive blocks of the copolymer. [less ▲]

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See detailSelf-assembly of poly(ethylene oxide)-b-poly(epsilon-caprolactone) copolymers in aqueous solution
Vangeyte, Pattrick; Leyh, Bernard ULg; Heinrich, M. et al

in Langmuir (2004), 20(20), 8442-8451

The associative behavior of monodisperse diblock copolymers consisting of a hydrophilic poly(ethylene oxide) block and a hydrophobic poly(epsilon-caprolactone) or poly(gamma-methyl-epsilon-caprolactone ... [more ▼]

The associative behavior of monodisperse diblock copolymers consisting of a hydrophilic poly(ethylene oxide) block and a hydrophobic poly(epsilon-caprolactone) or poly(gamma-methyl-epsilon-caprolactone) block has been studied in aqueous solution. Copolymers have been directly dissolved in water. The solution properties have been studied by surface tension, in relation to mesoscopic analyses by NMR (self-diffusion coefficients), transmission electron microscopy, and small-angle neutron and X-ray scattering. The experimental results suggest that micellization occurs at low concentration (approximately 0.002 wt %) and results in a mixture of unimers and spherical micelles that exchange slowly. The radius of the micelles has been measured (ca. 11 nm), and the micellar substructure has been extracted from the fitting of the SANS data with two analytical models. The core radius and the aggregation number change with the hydrophobic block length according to scaling laws as reported in the scientific literature. The poly(ethylene oxide) blocks are in a moderately extended conformation in the corona, which corresponds to about 25% of the completely extended chain. No significant modification is observed when poly(gamma-methyl-epsilon-caprolactone) replaces poly(epsilon-caprolactone) in the diblocks. [less ▲]

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See detailStructure and dynamics of cationic surfactants intercalated in synthetic clays
Müller, Robert; Hrobarikova, Jana; Calberg, Cédric ULg et al

in Langmuir (2004), 20(7), 2982-2985

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See detailSolid-state NMR study of poly(epsilon-caprolactone)/clay nanocomposites
Calberg, Cédric ULg; Jérôme, Robert ULg; Grandjean, Jean ULg

in Langmuir (2004), 20(5), 2039-2041

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See detailNa-23 2D 3QMAS NMR and Si-29, Al-27 MAS NMR investigations of Laponite and synthetic saponites of variable interlayer charge
Delevoye, Laurent; Robert, Jean-Louis; Grandjean, Jean ULg

in Clay Minerals (2003), 38

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See detailFreezing of water bound in lichen thallus as observed by H-1 NMR. 1. Freezing of loosely bound water in Cladonia mitis at different hydration levels
Haranczyk, Hubert; Grandjean, Jean ULg; Olech, M.

in Colloids and Surfaces B : Biointerfaces (2003), 28

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See detailNMR study of surfactant molecules intercalated in montmorillonite and silylated montmorillonite
Grandjean, Jean ULg; Bujdak, Janec; Komadel, Peter

in Clay Minerals (2003), 38

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See detailSurfactant molecules intercalated in laponite as studied by C-13 and Si-29 MAS NMR
Kubies, Dana; Jérôme, Robert ULg; Grandjean, Jean ULg

in Langmuir (2002), 18(16), 6159-6163

The structure and dynamics of surfactant molecules intercalated in Laponite have been characterized by solid-state C-13 NMR relaxation times and C-13- and Si-29-detected proton relaxation times. These ... [more ▼]

The structure and dynamics of surfactant molecules intercalated in Laponite have been characterized by solid-state C-13 NMR relaxation times and C-13- and Si-29-detected proton relaxation times. These results are compared to similar data obtained for a surfactant intercalated in montmorillonite and for different mesoporous materials. As compared with montmorillonite clay, a higher mobility and a greater percentage of the gauche conformation of the surfactant molecules are found in Laponite. The Si-29-detected proton relaxation times in the rotating frame are sensitive to the amount of intercalated surfactant. [less ▲]

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