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Differential Scanning Calorimetry Experiments (differential + scanning_calorimetry_experiment)
Selected AbstractsLipid Addition to Improve Barrier Properties of Edible Starch-based Films and CoatingsJOURNAL OF FOOD SCIENCE, Issue 6 2000M.A. García ABSTRACT: Effects of formulation (lipid presence, type of starch, and plasticizer) on microstructure, water vapor (WVP) and gas (GP) permeabilities of films and coatings were analyzed. Plasticizer was necessary to maintain film and coating integrity and to avoid pores and cracks. Films made from high amylose starch showed lower WVP and GP than regular corn starch films; permeabilities of films with sorbitol (20 g/L) were lower than those with glycerol. The addition of 2g/L sunflower oil to the formulations decreased WVP of starch-based films; X-ray diffraction and Differential Scanning Calorimetry experiments demonstrated that films with plasticizer and lipid showed lower crystalline-amorphous ratio compared to films without additives. Microstructural observations helped explain the decrease of the film permeabilities during storage. [source] Probing the antioxidative properties of combinations of an organotellurium compound, BHT and thiol in oilLUBRICATION SCIENCE, Issue 2 2006David Shanks Abstract Differential scanning calorimetry experiments with an unsaturated polyolester oil at 190°C showed that an organotellurium compound in combination with a thiol or a sterically hindered phenol (BHT) could act in a synergistic fashion to protect the material from oxidation. Under more realistic conditions for an oil antioxidant (elevated temperature in the presence of oxygen, water and a copper coil; rotating pressure vessel oxidation test) the antioxidant protection offered by the organotellurium/thiol and organotellurium/BHT combinations could not match the protection offered by BHT itself at similar concentrations. In order for the novel antioxidant systems to become useful for protection of oils and fluids, more robust organotellurium compounds must be prepared. Copyright © 2006 John Wiley & Sons, Ltd. [source] Bis(tetraethylammonium) hydrogensulfate dihydrogenphosphate at 292 and 150,KACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2003Jan Fábry The title compound, 2C8H20N+·HSO4,·H2PO4,, was crystallized in a desiccator over P4O10 from a water solution of stoichiometric amounts of tetraethylammonium hydroxide and sulfuric and phosphoric acids. The compound is deliquescent. The structure contains two symmetry-independent cations in nearly the same conformation, as well as two symmetry-independent anions, the central atoms of which are equally occupied by P and S. The anions are interconnected by short O,O hydrogen bonds into one-dimensional chains. The distances and angles between some of the methyl or methylene groups and anionic O atoms indicate the presence of C,H,O hydrogen bonds. The structure was determined from data at 292,(2) and 150,(2) K. These room- and low-temperature structures are virtually the same, with the exception of the localization of the H atoms that participate in the symmetry-restricted O,O hydrogen bonds. A differential scanning calorimetry experiment indicated no phase transition below the temperature at which the compound started to decompose (353,K), down to 93,K. [source] Preparation of poly(acrylonitrile,butadiene,styrene)/montmorillonite nanocomposites and degradation studies during extrusion reprocessingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009E.-K. Karahaliou Abstract In this study, the preparation of organically modified montmorillonite/poly(acrylonitrile,butadiene,styrene) (ABS) nanocomposites was studied by melt blending in a twin-screw extruder. The composite material was subjected to a series of five extrusion cycles, and the effect of reprocessing on the material's structural properties was investigated. More specifically, chemical changes were studied with attenuated total reflectance/Fourier transform infrared analysis, the thermal response was recorded by differential scanning calorimetry experiments, and the thermal stability was detected with thermogravimetric analysis. Also, the rheological properties of these blends were investigated via melt flow index tests as a measure of their processability during melt mixing and molding processes. Furthermore, the mechanical strength of the obtained mixtures was explored, and the observed interactions were interpreted in terms of the influence of each component on the functional properties of the final mixture. This attempt enriched our knowledge about the recycling of ABS, with the additional aspect of the use of collected data from more complex systems, that is, composite materials, where the montmorillonite nanoparticles play a role in the interactions initiated by repeated processing. The experimental results of this study show that the reprocessing of ABS/montmorillonite induced oxidation products, but the rheological, mechanical, and thermal properties and the thermal and color stabilities of the composites remained almost stable. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Molecular modelling of inclusion compounds from hydrophobic dyes and ,-cyclodextrinCOLORATION TECHNOLOGY, Issue 4 2009Ahmed El-Shafei This paper arises from studies aimed at developing new approaches to combining the fabric formation and coloration steps of fabric processing. A key aspect of these studies involved the evaluation of cyclodextrin (CD)-based compounds as hosts for dye molecules that could be released onto a fabric surface following fabric formation. In this study, experimental data from wide-angle X-ray diffraction and differential scanning calorimetry experiments were used in tandem with molecular modelling studies to confirm the formation of ,-CD,dye complex inclusion compounds and to demonstrate the utility of parameterised model number 3 (PM3) semi-empirical molecular modelling methods for predicting the nature of the preferred ,-CD,dye inclusion compounds. Calculations revealed that the inclusion compounds containing two dye molecules was preferred over the inclusion compound containing one dye molecule. Further, molecular modelling of the inclusion compound obtained using ,-CD linked to an epichlorohydrin-based oligomer and commercial disperse dyes showed inclusion compound formation to be an energetically favourable process. [source] | ||||||||||