Authors:C. Allais, G. Keller, P Lesieur, M. Ollivon, and F. Artzner
Polymorphism of trilaurin mixed with 4% of cholesterol was studied with a setup coupling calorimetry and phase characterisation
by in-situ X-ray diffraction (Microcalix). Four polymorphic forms were identified. Monotropic and enantiotropic transitions
were identified from the reconstruction of Gibbs free energy diagram which allows the control of trilaurin polymorphism.
Authors:Ellen Denise P. Almeida, Adjane A. Costa, Mairim R. Serafini, Fábia C. Rossetti, Juliana M. Marchetti, Victor Hugo V. Sarmento, Rogéria de S. Nunes, Mário Ernesto G. Valerio, Adriano A.S. Araújo, and Ana Amélia M. Lira
analytic techniques employed for this purpose, differential scanning calorimetry (DSC) and X-raydiffraction (XRD) play a prominent role because they are able to provide structural information on the dispersed particles, and they have been employed to
Authors:W. Engel, N. Eisenreich, M. Herrmann, and V. Kolarik
Time and temperature resolved X-ray diffraction was used for thermal analysis. Series of diffraction patterns were measured,
while the samples are heated/cooled stepwise or isothermally with freely selectable temperature programs.
The method was applied for the investigation of the phase transitions of ammonium nitrate and HMX (1,3,5,7-tetranitro-1,3,5,7-tetraaza-cyclooctane),
when the identification of phases was required. Its capability in the field of kinetics is demonstrated with the isothermal
investigation of the solid state reaction of ammonium nitrate with copper oxide and the non-isothermal investigation of the
high temperature corrosion of nickel, which was performed by means of a difference procedure. For obtaining structural details
peak fitting and Rietveld refinement were applied for the investigation of ammonium nitrate and HMX.
Authors:Alexandra Ioana Bucur, Raul Bucur, Titus Vlase, and Nicolae Doca
type of bonds, X-raydiffraction technique will help one identify the crystalline phases present and perform deeper studies related to crystallinity degree, ratio of phases present, elemental cell characteristics, etc. Typically, the calcium phosphate
The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.
DMSO-kaolinite complexes of low- and high-defect Georgia kaolinite (KGa-1 and KGa-2, respectively) were investigated by thermo-XRD-analysis.
X-ray patterns showed that DMSO was intercalated in both kaolinites with a d(001)-value of 1.11 nm (type I complex). The samples were gradually heated up to 170°C and diffracted by X-ray at room-temperature.
With the rise in temperature, due to the thermal evolution of the guest molecules, the relative intensity of the 1.11 nm peak
decreased and that of the 0.72 nm peak (neat kaolinite) increased indicating that the fraction of the non-intercalated tactoids
increased. The 1.11 peak disappeared at 130–140°C. During the thermal treatment of both complexes two additional peaks appeared
at 110 and 120°C, respectively, with d-values of 0.79–0.94 and 0.61–0.67 nm in DMSO-KGa-1 and 0.81–0.86 and 0.62–0.66 nm in DMSO-KGa-2, indicating the formation
of a new phase (type II complex). The new complex was obtained by the dehydration of type I complex and was composed of intercalated
DMSO molecules which did not escape. The new peaks disappeared at 150–160°C indicating the complete escape of DMSO.
Authors:M. Ollivon, G. Keller, C. Bourgaux, D. Kalnin, P. Villeneuve, and P. Lesieur
Coupling of time-resolved synchrotron X-ray diffraction
at both small and wide angles with differential scanning calorimetry is a
new technique that allows simultaneous characterization of thermal and structural
properties of a sample. The apparatus, called Microcalix, works between –30
and +230C at scanning rates comprised between 0.01 and 20C min–1
with a high sensitivity in both measurements using a single sample of small
volume (from about 1 to 20 μL). The last version of the instrument is
designed for laboratory bench and conventional source but preferably with
rotating anode or multilayered mirrors. Measurements under low pressure or
under shear as well as recordings of isothermal evolution are also possible.
The example of the study of polymorphism of a monounsaturated triglyceride
(PPO) will be presented as an application.
Thermal decomposition of natural siderite and goethite has been studied using Mössbauer spectroscopy and X-ray diffraction. Hematite and magnetite were the principal compounds formed during high temperature treatment of siderite. Natural goethite transformed to hematite at high temperatures. The crystal structures, stoichiometry and the nuclear magnetic properties of Fe-oxides formed are discussed.
Based upon the results of ac calorimetry and temperature scanning X-ray diffraction in the phospholipid/cholesterol system,
the phase diagram was constructed by taking into account the ripple structure. From the analysis of the cholesterol concentration
dependence of the modified ripple structure the cholesterol-rich state which lies in the higher cholesterol concentration
than 20 mol% in the phase diagram is proposed. It is proposed that this is a fundamental complex that appears generally in
Authors:A. Vértes, T. Turmezey, Á. Griger, M. Awad, and S. Nagy
The Mössbauer parameters of tin in aluminium matrix were studied and published in an earlier paper1. The aim of this work was to carry out investigations on tin in an aluminium alloy containing magnesium, silicon and lead beside the Mössbauer active tin. The effect of heat treatments on the formation of intermetallic compounds was studied by X-ray diffraction and by the Mössbauer spectra of119Sn.