X-ray diffraction and differential

Thus, chiral discrimination may be observed that differentiates the force-area curves of the enantiomers of some surfactants from their racemic modifications. Apparent phase changes in the monolayer can be related to parallel behavior in the crystalline state through X-ray diffraction and differential scanning calorimetry. Formation of racemic compounds and quasi-racemates can be observed in some cases. 

Figure 18.14. Simultaneous X-ray diffraction and differential thermal analysis of polyamide. Reproduced from Androsch et al. (1996), by permission of Elsevier, Ltd.

Two crystal modifications and an amorphous phase were found for 24 by X-ray diffraction and differential thermogravimetric analysis [91KFZ(3)78]. The structure of a complex formed from 3-[p-methylphenyl)amino]-4-[(p-methylphenyl)imino]-4//-pyrido [1,2-a]pyrazine, sodium bis(trimethylsi-lyl)amide and (norbomadiene)Mo(CO)4 in THF was characterized by single-crystal X-ray diffraction [95JPR(337)38],... 

Ollivon, M., Loisel, C., Lopez, C., Lesieur, P., Artzner, F., Keller, G. 2001. Simultaneous examination of structural and thermal behaviours of fats by coupled X-ray diffraction and differential scanning calorimetry techniques application to cocoa butter polymorphism. In, Crystallization and Solidification Properties of Lipids (N. Widlak, R. Hartel, S. Narine, eds.), pp. 34-41, AOCS Press, Champaign, IL. 

In this chapter we investigate the morphology of a series of polyurethanes based on polycaprolactone polyol (PCP), diphenylmethane diisocyanate (MDI), and butanediol (BDO). Samples of as-batch-reacted and solution-cast polymers were examined by optical microscopy, transmission electron microscopy, electron and x-ray diffraction, and differential scanning calorimetry. Our interest is to provide a mapping of the size and shape of the domains (and any superstructure such as spherulites) and the degree of order as a function of the fraction of each phase present. 

Wilkes, G. L., Nguyen, A. L. and Wildnauer, R. (1973). Stmcture-property relations of human and neonatal rat stratum comeum. 1. Thermal stability of the crystalline lipid stmcture as studied by x-ray diffraction and differential thermal analysis. Biochim. Biophys. Acta 304 267. 

Simultaneous Examination of Structural and Thermal Behaviors of Fats by Coupled X-ray Diffraction and Differential Scanning Calorimetry Techniques Application to Cocoa Butter Polymorphism... 

Previous works reported on the study of the freezing process of aqueous solutions of ethanol in relation with the phase diagram. They were focused on the identification of different stable or metastable ethanol-hydrate structures using X-ray diffraction and differential scanning calorimetry (DSC). They also mentioned the formation of clathrate hydrates. In spite of the familiarity of alcohol-water systems and their importance in many fields of chemistry, cryobiology, astrophysics, there are still significant discrepancies in the literature with uncertainties concerning the composition and the structure of the stable or metastable eutectic or peritectic hydrates. ... 

Copolymers containing up to 35 wt % carboxylated vinyl ether were synthesized by regulating reaction pressure of the tetrafluoroethylene in the polymerization. X-ray diffraction and differential scanning calorimetry showed that the crystallinity of the copolymer decreased with increasing vinyl ether content. 

A Makriyannis, T Mavromoustakos. Studies on drug-membrane interactions using solid state NMR, small angle X-ray diffraction, and differential scanning calorimetry. Epitheor Klin Farmakol Farmakokinet, Int Ed 3 95-114, 1989. 

G. Z. Papageorgiou, G. P. Karayannidis, D. N. Bikiaris, A. Stergiou, G. Lit-sardakis, and S. S. Makridis. Wide-angle x-ray diffraction and differential scanning calorimetry study of the crystallization of poly(ethylene naphthalate), poly(butylene naphthalate), and their copolymers. J. Polym. ScL, Part B Polym. Phys., 42(5) 843-860, March 2004. 

Papageorgiou GZ, Karayannidis GP, Bikiaris DN, Stergiou A, Litsardakis G, Makridis SS, et al. Wide-angle x-ray diffraction and differential scanning calorimetry study of the crystallization of poly(ethylene naphthalate). 

State of the atomized powders during preparation and consolidation in a well-controlled atmosphere. Furthermore, considering that no distinct contrast revealing the precipitation of a crystalline phase is seen in the cross-sectional structure, extrusion at 373 K is suitable enough to keep the nonequilibrium phase in the as-quenched state. The absence of a crystalline phase in the extruded bulk alloy has been confirmed by X-ray diffraction and differential scaiming calorimetric analyses for the bulk MggsYioCus alloy extruded at 373 K. 

A combination of X-ray diffraction and differential scanning calorimetry has been used to probe the properties of a homologous series of saturated l,2-di-0-acyl-2-0-(P-D-galactopyranasyl)-sn-... 

Tactic pair contents were determined for two stereoblock fractions by a method based on the methyl proton resonances. Their results revealed much higher stereoblock characters than those determined for the same fractions from melting data. All PMR results were in very good accord with the results obtained on several polymers by infrared (IR), X-ray diffraction, and differential thermal analysis. 

Altunbas and Harris (1980) studied the cerium-praseodymium alloy system using electrical resistivity. X-ray diffraction and differential thermal analysis (DTA) techniques. In most of the research they used standard commercial material but some relatively pure praseodymium (purified by solid state electrolysis) was used in the DTA measurements. Appropriate amounts of the component metals were arc-melted in purified argon, turned and remelted several times. This was followed by a seven day vacuum anneal at 600°C with slow cooling to room temperature. Their electrical resistivity curves for the praseodymium sample indicated only one solid phase transformation (dhep bcc) whereas the curves for cerium and the Ce-Pr alloys exhibited two transitions, dhep fee (below 61°C for pure cerium) and fee bcc. 

We can investigate a polymer s molecular and supermolecular organization in various ways, which provide information on either a direct or indirect basis. For instance, microscopy of various types provides us with images of small regions of polymers, allowing us to directly visualize certain types of structure. Other methods, such as X-ray diffraction and differential scanning calorimetry, sample larger volumes of material and provide information representative of the material as a whole. 

Electrochemical synthesis of polyacetylene was carried out with platinum foil as cathode and nickel foil as anode with nickel bromide in acetonitrile as an electrolyte at room temperature to precipitate in the form of powder in the cell [101]. Chen and Shy [53] observed a thin layer of black material on a surface of the platinum cathode when a voltage of 4-40 V was applied for about 50 min. During this stage, no precipitation of polyacetylene was observed in the solution. The material has the same chemical structure as those produced by the standard Ziegler-Natta catalyst as examined by elemental analysis, infrared spectroscopy. X-ray diffraction, and differential scanning calorimetry. 

Fieldes [1968] has studied subsoils of suites of brown loams and red loams, soils of increasing maturity derived from basalt. Relative proportions of amorphous (allophanic) constituents, kaolin, and gibsite were assessed by X-ray diffraction and differential thermal analysis. Results are listed in Table 7. The following points are observed ... 

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