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Infrared Absorption Spectra (infrared + absorption_spectrum)

Distribution by Scientific Domains

Chemistry	60%
Polymers and Materials Science	40%

Selected Abstracts

Preparation, morphology and electrical conductivity of polyaniline/polyoxyalkylene,montmorillonite exfoliated nanocomposites

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2008
N. Salahuddin
Abstract Polyaniline (PANI)/organoclay exfoliated nanocomposites containing different organoclay contents (14,50,wt%) were prepared. PANI emeraldine base (EB) and oligomeric PANI (o-PANI) were intercalated into montmorillonite (MMT) modified by four types of polyoxyalkylene diamine or triamine (organoclay) using N-methyl pyrolidinone (NMP) as a solvent in the presence of 0.1,M HCl. o-PANI and EB have been synthesized by oxidative polymerization of aniline using ammonium peroxydisulfate (APS). Infrared absorption spectra (IR) confirm the electrostatic interaction between negatively charged surface of MMT and positively charged sites in PANI. X-ray diffraction (XRD) studies disclosed that the d001 spacing between interlamellar surface disappeared at low content of the organoclay. The morphology of these materials was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrical conductivities of the PANI-organoclay and o-PANI-organoclay nanocomposites were 1.5,×,10,3,2,×,10,4 and 9.5,×,10,7,1.8,×,10,9,S/cm, respectively depending on the ratio of PANI. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Synthesis and Characterization of Hydroxyapatite/Poly(Vinyl Alcohol Phosphate) Nanocomposite Biomaterials

INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 1 2008
Nabakumar Pramanik
A hydroxyapatite (HAp)/poly(vinyl alcohol phosphate) (PVAP) nanocomposite has been prepared by a chemical method by varying the HAp content by 10,60% (w/w). The bonding between HAp and PVAP has been investigated through Fourier transform infrared absorption spectra, X-ray diffraction, and thermogravimetric analyses. Transmission electron microscopy study shows a homogeneous dispersion of nanoparticles in the polymer matrix. Scanning electron microscopy study shows enhancement of the surface roughness of the composite with an increase in the nanoparticle content. The mechanical properties of the composites improve significantly with an increase in the HAp content. The HAp/PVAP nanocomposite prepared may have bone,implant applications. [source]

Vibrational spectra of bis(L -ornithinium) chloride nitrate sulfate

JOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2005
S. Ramaswamy
Abstract The Raman and infrared absorption spectra of 2(C5H14N2O22+)·Cl,·NO3,·SO42, crystal containing three anions were recorded at room temperature and were interpreted in the light of crystal structure data. The presence of a carbonyl group was identified. The carboxylic group was found to exist as COOH. The formation of OH···O, NH···O and NH···Cl asymmetric hydrogen bonds contributes considerably to the crystal cohesion and is responsible for the changes in the position and intensity of several bands. The vibrational spectra show that the anions were found to coordinate through hydrogen bonding interactions to other ligands in the crystal. The lattice wavenumbers of the halide radical (chlorine anion) were also assigned in terms of hydrogen bond vibrations. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Infrared Spectra of Protonated Uracil, Thymine and Cytosine

CHEMPHYSCHEM, Issue 15 2007
Jean-Yves Salpin Dr.
Abstract The gas-phase structures of protonated uracil, thymine, and cytosine are probed by using mid-infrared multiple-photon dissociation (IRMPD) spectroscopy performed at the Free Electron Laser facility of the Centre Laser Infrarouge d,Orsay (CLIO), France. Experimental infrared (IR) spectra are recorded for ions that were generated by electrospray ionization, isolated, and then irradiated in a quadrupole ion trap; the results are compared to the calculated infrared absorption spectra of the different low-lying isomers (computed at the B3LYP/6-31++G(d,p) level). For each protonated base, the global energy minimum corresponds to an enolic tautomer, whose infrared absorption spectrum matched very well with the experimental IRMPD spectrum, with the exception of a very weak IRMPD signal observed at about 1800 cm,1 in the case of the three protonated bases. This signal is likely to be the signature of the second-energy-lying oxo tautomer. We thus conclude that within our experimental conditions, two tautomeric ions are formed which coexist in the quadrupole ion trap. [source]