Fourier transform infrared absorption, FTIR

The role of specific interactions in the plasticization of PVC has been proposed from work on specific interactions of esters in solvents (eg, hydrogenated chlorocarbons) (13), work on blends of polyesters with PVC (14—19), and work on plasticized PVC itself (20—23). Modes of iateraction between the carbonyl functionaHty of the plasticizer ester or polyester were proposed, mostly on the basis of results from Fourier transform infrared spectroscopy (ftir). Shifts in the absorption frequency of the carbonyl group of the plasticizer ester to lower wave number, indicative of a reduction in polarity (ie, some iateraction between this functionaHty and the polymer) have been reported (20—22). Work performed with dibutyl phthalate (22) suggests an optimum concentration at which such iateractions are maximized. Spectral shifts are in the range 3—8 cm . Similar shifts have also been reported in blends of PVC with polyesters (14—20), again showing a concentration dependence of the shift to lower wave number of the ester carbonyl absorption frequency. 

In the present study, we synthesized in zeolite cavities Co-Mo binary sulfide clusters by using Co and Mo carbonyls and characterized the clusters by extended X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and high resolution electron microscopy (HREM). The mechanism of catalytic synergy generation in HDS is discussed. 

The hydrogen content Ch greatly influences structure and consequently electronic and optoelectronic properties. An accurate measurement of Ch can be made with several ion-beam-based methods see e.g. Arnold Bik et al. [54]. A much easier accessible method is Fourier-transform infrared transmittance (FTIR) spectroscopy. The absorption of IR radiation is different for different silicon-hydrogen bonding configurations. The observed absorption peaks have been indentified [55-57] (for an overview, see Luft and Tsuo [6]). The hydrogen content can be determined from the absorption peak at 630 cm , which includes... 

Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance spectroscopy ( ll NMR) have become standards for verifying the chemistry of polyanhydrides. The reader is referred to the synthesis literature in the previous section for spectra of specific polymers. The FTIR spectrum for PSA is shown in Fig. 2. In FTIR the absorption... 

Fourier transform Infrared spectroscopy has been shown to be an excellent tool for surface and Interface studies (.2), In this paper, the application of reflection/absorption Fourier transform Infrared spectroscopy (FTIR-RA) for studying the degradation of amine-cured epoxy and polybutadiene coatings on cold-rolled steel after exposure to a warm, humid environment is reported. 

Analyses of the chloroform-soluble extracts of the subbituminous coal by Fourier transform infrared spectroscopy (FTIR) showed the presence of a sharp carbonyl absorption peak (1800-1650 cm ) in the extracts from the parent coal and in those obtained at yields less than about 10% wt dmmf. The peak, which is attributed to ketones and carboxylates, disappeared at higher conversions (16). Whitehurst and co-workers (12) established that carbonyl- containing compounds, such as esters and carboxylates, can cleave under thermal treatment to produce CO, CO2 and phenols. They concluded that the evolution of these gases during coal liquefaction could originate from the decomposition of similar oxygen functionalities in the coal. 

Fourier transform infrared spectroscopy (FTIR) can give useful information on chemical changes occurring in the system. However, the detection of such changes can be challenging because often the new species produced are present in small amounts and they are chemically similar to the initial material, so their absorption peaks are masked. 

Fourier transform infrared spectroscopy (FTIR) was also used to study the anisotropic structure of polyimide films. This work was based on the fact that there are characteristic absorptions associated with in-plane and out-of-plane vibrations of some functional groups, such as the carbonyl doublet absorption bands at 1700-1800 cm . The origin of this doublet has been attributed to the in-phase (symmetrical stretching) and out-of-phase (asymmetrical stretching) coupled... 

Huvenne and Lacroix described a mathematical procedure for the correlation of band intensities of the Fourier-transform infrared absorption spectra with those of the corresponding infrared transmission spectra of compounds in KBr discs [22]. The procedure was applied to spectra of flunitrazepam, dipyridamole, and lactose that were obtained through the use of a Nicolet 7199 B FTIR spectrometer with photoacoustic detection. When the photoacoustic spectrum of a plant charcoal was used to correct the spectra for inequalities in the incident light flux before applying the procedure, the correlated band intensities were generally consistent with those obtained using infrared transmission spectra. The procedure may be useful for the direct identification of the drugs. 

Spectroscopic investigations of the speciation of solid phases encountered as trapped particulate material in lichen biomass. Particular emphasis should be placed on understanding the dissolution of trapped particles and the precipitation of secondary solid phases on or within the thallus and their relationship with organic phases in the lichen. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) in parallel with microscopy studies would be particularly useful in such investigations. 

The experiments were performed in two different ultra high vacuum (UHV) chambers using two different Pt(lll) single crystals. The X-ray photoelectron spectra were obtained in a chamber with a base pressure of lxlO" Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped with low energy electron diffraction (LEED), an X-ray photoelectron spectrometer (XPS), a quadrupole mass spectrometer (QMS) for temperature programmed desorption (TPD), and a Fourier transform infrared spectrometer (FTIR) for reflection absorption infrared spectroscopy (RAIRS). All RAIRS and TPD experiments were performed in a second chamber with a base pressure of 2 X 10 ° Torr. The system has been described in detail elsewhere. In brief, the UHV chamber is equipped for LEED, Auger electron spectroscopy (AES) and TPD experiments with a QMS. The chamber is coupled to a commercial FTIR spectrometer, a Bruker IFS 66v/S. To achieve maximum sensitivity, an... 

A rapid Fourier transform infrared spectroscopy (FTIR) method based on the stoichiometric reaction of triphenylphosphine (TPP) with hydroperoxides has been developed and successfully applied to determination of PV of edible oils (32). The hydroperoxides present in oil samples react stoichiometrically with TPP to produce triphenylphosphine oxide (TPPO), which has an intense absorption... 

A method of horizontal attenuated total reflectance (HATR) by Fourier transform infrared spectroscopy (FTIR) is considered more useful for infrared spectroscopic analysis of leather samples. By this method, the sample is simply put on the flat plate of ZnSe crystal or KRS-5 crystal of the HATR accessory. The Fourier transformation of the interferogram is converted by the computer into a plot of absorption against wave number that resembles the usual IR spectrum (William and Fleming, 1998). 

The most attractive sensors now being developed are the Fourier transform infrared spectrometer (FTIR) and the near-infrared (NIR) spectrometer for the on-line measurement of composition changes in complex media during cultivation. The FTIR measurements are based on the type and quantities of infrared radiation that a molecule absorbs. The NIR measurements are based on the absorption spectra following the multi-regression analyses. These sensors are not yet available for fermentation processes. 

An application of Fourier transform infrared spectroscopy (FTIR) to maleated polypropylene-treated wood liber has indicated that esterification reaction between hydroxyl groups of lignilied liber (unbleached thermomechanical pulp, TPM) and the coupling agent does not occur [5], The FTIR spectra did not indicate the presence of any distinct absorption bands near 1730 cm, which may be associated to other ester links besides those already present in wood fiber. However, tensile and flexural strength and impact resistance of the WPC in the presence of the maleated polypropylenes increased significantly (up to 280%) (Tables 5.9 and 5.10). 

A Nicolet Magna 550 Fourier Transform Infrared Spectrometer (FTIR) and a Bruker MW 250 MHz proton NMR were used to verify the chemical structure of all monomers and polymers. Optical activity of the compounds was measured at 25 on a Perkin-Elmer Polarimeter in chloroform. A Waters Gel Permeation Chromatograph with 440 UV absorption detector and R401 differential refructometer was used to determine the molecular weights of the polymers tetrahydrofuran was used as the mobile phase at 1.0 mL/min, and the Waters polystyrene gel columns were calibrated with monodisperse polystyrene standards. Polarizing optical microscopy was used to identify liquid crystalline phases using a Leitz optical microscope with a CCD camera attachment... 

Chemical analysis of hazardous substances in air, water, soil, sediment, or solid waste can best be performed by instrumental techniques involving gas chromatography (GC), high-performance liquid chromatography (HPLC), GC/mass spectrometry (MS), Fourier transform infrared spectroscopy (FTIR), and atomic absorption spectrophotometry (AA) (for the metals). GC techniques using a flame ionization detector (FID) or electron-capture detector (BCD) are widely used. Other detectors can be used for specific analyses. However, for unknown substances, identification by GC is extremely difficult. The number of pollutants listed by the U.S. Environmental Protection Agency (EPA) are only in the hundreds — in comparison with the thousands of harmful... 

Framework and Surfaces Since compositions and structures are very diverse, surface and framework properties are also extremely varied. In terms of compositions, coordination, and chemical environments, several methods are particularly informative for the characterization of nanoporous solids, such as nuclear magnetic resonance methods (NMR), UV-visible spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray absorption spectroscopies, x-ray photoelectron emission spectroscopy (XPS), and electron paramagnetic resonance (EPR) (4, 6). Among them, sohd state NMR techniques arc largely employed and will be briefly described in the following. 

The use of Fourier-transformed infrared spectroscopy (FTIR) in particles produced by spray chilling mainly predicts the detection of possible interactions between the active ingredient and the lipid carrier. Normally, the analysis individually studies the components (matrix and active compound, and other components, when available) that will form the capsules. Specific absorption bands will be observed in determined regions or in a specific wavelength. After that, the analysis of the microparticles that are already formed is carried out. The discussion involves changes in the absorption bands of ingredients and formed microparticles, with the comparison of the peaks observed in both cases. 

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