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Infrared Spectroscopic Studies (infrared + spectroscopic_studies)
Selected AbstractsCompatible blends of ethylene-vinyl acetate copolymer and hydrogenated nitrile rubberADVANCES IN POLYMER TECHNOLOGY, Issue 1 2004P. Thavamani Abstract The miscibility and some physico-mechanical characteristics of ethylene vinyl acetate (EVA) copolymer and hydrogenated nitrile rubber (HNBR) have been investigated using differential scanning calorimetry, dynamic mechanical and thermal analysis, and electrical conductivity. EVA was found to be miscible with HNBR at all properties. Infrared spectroscopic studies revealed that there is some chemical interaction between the constituent polymers. Scanning electron microscopic observations on the morphology of preferential solvent extracted samples indicated that in the blend the major constituent forms a continuous matrix in which the minor one is dispersed. At equal proportions, both EVA and HNBR exist as discontinuous phase. Variation of strength properties with blend composition is also discussed. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 5,17, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10066 [source] XRD, thermal, FTIR and SEM studies on gel grown ,-glycine crystalsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2007E. Ramachandran Abstract Glycine is the smallest among amino acids. The polymorphs, ,- and ,-forms of glycine were crystallized in silica gel by reduction of solubility method. The grown crystals were characterized by single crystal X-ray diffraction studies and density determination. Fourier transform infrared spectroscopic studies and thermogravimetric analysis of ,-glycine were also conducted. Morphological and scanning electron microscopic (SEM) studies were also made and compared with the crystal packing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Aminoethyl-Functionalized Cyclopentadienyliridium Complexes: Photochemical C,H Activation and Carbonylation of CycloalkanesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2006Pek Ke Chan Abstract The photochemical C,H activation of cycloalkanes by aminoethyl-functionalized cyclopentadienyliridium complexes proceeds in a broadly similar way to that for their unfunctionalized analogues. In a carbon monoxide atmosphere, there is evidence that carbonylation to form the carboxaldehyde occurred with both systems. In situ infrared spectroscopic studies on these reactions allow the identification of several species present in low concentrations in the reaction mixture. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Dual-Tone Patterned Mesoporous Silicate Films Templated From Chemically Amplified Block CopolymersADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Sivakumar Nagarajan Abstract Directly patterned mesoporous silicate films are prepared using positive- and negative-tone strategies by performing phase selective silica condensation within lithographically exposed poly(styrene- b - tert -butyl acrylate) (PS- b -PtbA) templates containing photoacid generators. The use of supercritical fluid as a process medium enables rapid diffusion of the silicate precursor within the prepatterned block copolymer template film without disrupting its morphology. Template exposure through the mask triggers area selective generation of acid, which in turn both deprotects the poly(tert -butyl acrylate) block to yield a poly(acrylic acid) block and provides a catalyst for silica precursor condensation yielding pattern formation at the device level. Because the acid generated in the UV exposed field preferentially segregates into hydrophilic poly(acrylic acid) domains of the phase segregated, deprotected block copolymer, precursor condensation is simultaneously controlled at nanoscopic length scales via templating by the underlying block copolymer morphology. The ability of PS- b -PtbA to undergo chemical transformation in two stages, deprotection followed by crosslinking, enables precise replications of the photomask in positive and negative tones. Detemplating via calcination yields patterned mesoporous silicate films without etching. Template formulations are optimized using infrared spectroscopic studies and the silicate films are characterized using electron microscopy and scanning force microscopy. [source] Study of the Dehydroxylation,Rehydroxylation of PyrophylliteJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2010Jose L. Perez-Rodriguez Pyrophyllite is a raw material of significant interest due to its large number of applications. Most of these applications require a thermal transformation of pyrophyllite; this thermal transformation implies the release of structural OH groups and the formation of new phases. In this paper, we report on the dehydroxylation of pyrophyllite and the reversibility of the process. A value of 224±16 kJ/mol for the dehydroxylation of pyrophyllite was obtained. In addition, it was observed that the partially or totally dehydroxylated pyrophyllite suffered a partial reversible rehydroxylation when cooled to room temperature. This rehydroxylation was substantiated by thermogravimetric measurements, while infrared spectroscopic studies showed that, during the rehydroxylation, the intensity of the OH band at 3675 cm,1 increased as two new bands at 3690 and 3702 cm,1 appeared. This rehydroxylation process was heavily influenced by the particle size of the pyrophyllite. Thus, smaller particles (<1 ,m) showed a larger rehydroxylation percentage (about 12%), while the larger ones (20,40 ,m) showed a smaller percentage (about 1.6%). The extent of rehydroxylation also depended on the dehydroxylation temperature and reached a maximum value at 750°C. [source] Formation of Hydrophobic Silica Coatings on Stones for Conservation of Historic SculpturesCHINESE JOURNAL OF CHEMISTRY, Issue 8 2010Feigao Xu Abstract The conservation of historic sculptures is receiving growing attention because of the increasing air pollution. A hydrophobic silica coating was synthesized to protect historic sculptures from weathering by starting from a solution of tetraethoxyorthosilicate (TEOS) precursor using hexadecyltrimethoxysilane (HDTMS) as hydrophobic modifier in the presence of ammonia as a catalyst. The molar ratio of ethanol, TEOS, H2O and NH4OH was kept constant at 8:0.045:3:2.8 and the molar ratio of HDTMS/TEOS (M) was varied from 0 to 0.458. The organic modification was confirmed by infrared spectroscopic studies, and the hydrophobicity of the coating was tested by the contact angle measurements. The stone surface morphology of sample treated with silica coating was characterized. The results showed that the nanocomposites were composed of spherical particles with grain size of about 190 nm in diameter. After the limestone's surface was modified, the contact angle of limestone increased from 20° to 100° for M0.458. The protective performance evaluated with its ability to resist acid rain reveals that the protective effects are satisfying. [source] | |||||||||||||