Results 301 to 310 of about 56,158 (342)

Evolution of Benzylammonium-Vermiculite and Ornithine-Vermiculite Intercalates

Clays and Clay Minerals, 1996
AbstractThis report consists of a study of l-ornithine hydrochloride-vermiculite and of benzylammonium hydrochloride-vermiculite complex. The evolution of these organo-vermiculite structures upon heating is studied by X-ray diffraction (XRD) as well as infrared spectroscopy.After heating vermiculite saturated with 1-ornithine cations, it shows ...
C. de la Calle, M. I. Tejedor, C. H. Pons   +2 more
openaire   +1 more source

Thermal study of vermiculites and mica-vermiculite interstratifications

Journal of Thermal Analysis, 1993
Simultaneous DTA-TG has been carried out on a set of natural vermiculite samples. Based on their dehydration behaviour the samples can be divided in two groups: (a) those with DTA endothermic peak temperatures at 140°–150°C and 240°–270°C (pure vermiculties) and (b) those with peak temperatures at 95°–115°C (vermiculite with mica or mica-vermiculite ...
A. Justo, J. L. Pérez-Rodríguez, P. J. Sánchez-Soto   +2 more
openaire   +1 more source

Modelling of Aniline-Vermiculite and Tetramethylammonium-Vermiculite; Test of Force Fields

Journal of Molecular Modeling, 1999
Molecular mechanics simulations in Cerius2 have been used for modelling vermiculite intercalated with tetramethylammonium and aniline cations. The published structure data obtained for these intercalated structures from X-ray single crystal diffraction have been used to test the force fields and modelling strategy for organo-clays.
Capkova, P., Burda, J.V., Weiss, Z., Schenk, H.   +3 more
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Complexes vermiculite—aminoacides

Clay Minerals, 1971
AbstractVermiculite single crystals immersed in aminoacid solutions of varying concentration and pH, form complexes characterized by discrete basal spacings. Organic molecules enter in the interlayer space as cations and as dipolar ions through mechanisms of ion exchange and dipole adsorption.The basal spacings of the complexes were recorded.
J. A. Rausell-Colom, P. S. Salvador
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Vermiculite et vermiculitisation

Bulletin du Groupe français des argiles, 1972
Wey Raymond, Le Dred Ronan. Vermiculite et vermiculitisation. In: Bulletin du Groupe français des argiles. Tome 24, fascicule 2, 1972. pp. 111-134.
Wey, Raymond, Le Dred, Ronan
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The Structures of Ornithine-Vermiculite and 6-Aminohexanoic Acid-Vermiculite

Clays and Clay Minerals, 1976
AbstractFourier syntheses have been used to establish the arrangement of organic molecules in the interlamellar regions of a 16.10 Å phase of ornithine-vermiculite and a 16.92 Å phase of 6-aminohexanoic acid-vermiculite. The organic cations form two layers parallel to the silicate surfaces in ornithine-vermiculite and in 6-aminohexanoic acid ...
P. G. Slade, M. I. Telleria, E. W. Radoslovich   +2 more
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Vermiculite Surface Morphology

Clays and clay minerals (National Conference on Clays and Clay Minerals), 1963
AbstractA study of the surface morphology of vermiculites from several different sources by the electron microscope has indicated that, unlike the smooth surfaces of micas, the vermiculite surfaces show micromorphological structural variations such as small humps, prominent crystallographic steps on the basal cleavage planes, marginal rolling of the ...
K. V. Venkata Raman, M. L. Jackson
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Dehydration and rehydration of vermiculites: III. Phlogopitic Sr- and Ba-vermiculite

Clay Minerals, 1997
AbstractDehydration and rehydration of a phlogopitic vermiculite saturated with either Sr2+ or Ba2+ were studied by thermoanalysis (TG, DSC, DTA) and by in situ X-ray powder diffractometry. A detailed analysis of the relationship between temperature and state of hydration of the vermiculites close to equilibrium at atmospheric pressure was rendered ...
H. Graf v. Reichenbach, J. Beyer
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Thermal resistance of hardened cement pastes containing vermiculite and expanded vermiculite

Journal of Thermal Analysis and Calorimetry, 2011
The durability and thermal stability of hardened Portland cement pastes containing vermiculite (V) and expanded vermiculite (EV) exposed to high temperatures were studied. Different mixtures were prepared using 2.5, 5, and 10 wt% of both types of V. Each mixture, after 28 days of hydration, was heated at 300, 600, and 800 °C for 3 h.
S. M. A. El-Gamal, F. S. Hashem, M. S. Amin   +2 more
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Interstratification in Vermiculite

Clays and Clay Minerals, 1967
AbstractVermiculite (Libby, Mont.) was ground in a Waring blender in a 1 m NaCl solution and, after removal of excess electrolyte, the clay fraction was separated by sedimentation. The clay was predominantly vermiculite: X-ray diffraction patterns of Ca-saturated and oriented specimens showed an intense and sharp 15 Å and a weak 25 Å diffraction maxima
openaire   +1 more source