Showing papers on "Fourier transform infrared spectroscopy published in 1979"
01 Aug 1979
421 citations
TL;DR: Polarized Fourier transform infrared spectroscopy has been used to study the structure of purple membrane from Halobacterium halobium, finding the average orientation of the alpha-helices was found to lie in a range of less than 26 degrees away from the membrane normal, agreeing with electron microscopic measurements.
218 citations
TL;DR: In this article, Fourier transform infrared (FTIR) studies of poly(ϵ-caprolactone) (PCL) and polyvinyl chloride (PVC) blend systems are presented.
Abstract: Fourier-transform infrared (FTIR) studies of the poly(ϵ-caprolactone) (PCL)–poly(vinyl chloride) (PVC) blend system are presented. The results indicate that there are specific interactions between the PCL and PVC in both the molten and solid states which could be responsible for the apparent compatibility of the amorphous component of these blends. Additionally, FTIR difference spectra are presented to illustrate the potential of this technique for following the kinetics of crystallinity in polymer blend systems.
212 citations
TL;DR: In this paper, a high surface area silica powder is used to study the coupling agent/matrix interface and the structural basis for the mechanical performances of fiberglass reinforced plastics (FRP) is studied on the molecular level using Fourier transform infrared spectroscopy (FT-IR).
Abstract: The mechanical performances of fiberglass reinforced plastics (FRP) are quite different when the glass fibers are treated with vinyl (VS) and methacryl (γ-MPS) functional silane coupling agents. We have studied the structural basis for this difference on the molecular level using Fourier transform infrared spectroscopy (FT-IR). A high-surface-area silica powder is used to study the coupling agent/matrix interface. Both VS and γ-MPS can react with styrene at the interface. However, when E-glass fiber is used as a substrate, only γ-MPS polymerizes in the coupling agent interphase which consists of many layers of coupling agent molecules while the major portion of the VS does not polymerize in the interphase. The effect of glass surfaces, with and without a coupling agent, on the curing of the polyester resin has also been studied. Silane coupling agents participate in the curing of the polyester resin while untreated E-glass fiber surfaces inhibit the polymerization resulting in different structures from the bulk matrix.
100 citations
TL;DR: In this article, a general method for direct measurement of differential absorption intensities using a Fourier transform infrared spectrometer is described, and specific expressions are presented for the measurement of circular and linear dichroism.
Abstract: A general method for the direct measurement of differential absorption intensities using a Fourier transform infrared spectrometer is described. The differential intensities must be higher in frequency than the interferogram frequencies and may arise from a periodic variation of the absorption strength of the sample, or by dichroic response of the sample to alternate states of polarization of the infrared beam. Specific expressions are presented for the measurement of circular and linear dichroism. These expressions represent an extension of the Grosjean-Legrand polarization modulation technique to Fourier transform interferometry.
94 citations
TL;DR: The feasibility of applying the methods of factor analysis to Fourier transform infrared spectra is examined in this article, where the method is designed to determine the number of components contributing to a spectral region.
Abstract: The feasibility of applying the methods of factor analysis to Fourier transform infrared spectra is examined. The method is designed to determine the number of components contributing to a spectral region. The technique has been applied to a model system consisting of solutions of p-, o-, and m-xylenes. The method has also been used for calculating the number of independently absorbing species in several polymer systems. Spectral requirements and the general applicability of factor analysis are also discussed.
78 citations
TL;DR: Fourier transformed photoacoustic IR spectroscopy of a solid is demonstrated for the first time in this paper, where an uncorrected spectrum of polystyrene film is shown to be fairly readily obtained, although multiple interferometer-scan averaging is required.
76 citations
IBM1
TL;DR: In this paper, it has been shown that compared to a bulk sample the scattering volume in the thin film has increased by 1 to 2 orders of magnitude which results in a Raman spectrum with considerably higher signal/noise ratio.
Abstract: Raman spectroscopy of polymer films using integrated optics has been shown to be a general technique applicable to films with thicknesses as small as 1 μ. With this technique no apparent interference from spectral features due to the substrate has been observed. It has been shown that compared to a bulk sample the scattering volume in the thin film has increased by 1 to 2 orders of magnitude which results in a Raman spectrum with considerably higher signal/noise ratio.
69 citations
TL;DR: Fourier transform infrared transmission spectroscopy is presented as a technique with great potential for the study of aqueous membrane preparations and the methodology of sample preparation, spectra recording and data reduction is outlined.
68 citations
TL;DR: In this paper, Fourier transform infrared (FTIR) spectroscopy was used for measurement of epoxy resins under various degradation conditions by Fourier Transform Infrared Spectroscopy for measurement, and the authors found that the oxidative thermal and photodegradation processes were related to the classical autocatalytical oxidation of aliphatic hydrocarbon segments.
Abstract: Three cured epoxy resins were investigated under various degradation conditions by Fourier transform infrared (FTIR) spectroscopy for measurement. The epoxy resins were the diglyadyl ethers of bisphenol A (DGEBA), phenolphthalein (DGEPP), and 9,9-bis(4-hydroxyphenyl)fluorene (DGEBF). The thermal stability order of functional groups that incurred DGEBA was total methyl group ∼ total benzene ring > methylene > p-phenylene > ether linkage > isopropylidene. The oxidative thermal and photodegradation processes were found to be related to the classical autocatalytical oxidation of aliphatic hydrocarbon segments. The Wieland rearrangement, Norrish-type reaction, Claisen rearrangement, and other possible degradation mechanisms were suggested by the data.
64 citations
TL;DR: The original double-beam Michelson-type Fourier spectrometer at the University of Oulu has been partly modified so that a maximum resolution of slightly better than 0.010 cm(-1) between 20 cm (-1) and 1200 cm(- 1) can be obtained.
Abstract: The original double-beam Michelson-type Fourier spectrometer at the University of Oulu has been partly modified so that a maximum resolution of slightly better than 0.010 cm−1 between 20 cm−1 and 1200 cm−1 can be obtained. The resolution is determined as a halfwidth of an observed line. The accuracy of the line position is 0.0005 cm−1 in favorable conditions. The Fourier spectrometer is connected on-line to a minicomputer, in order to make the fast Fourier transforms of interferograms of up to 106 sampling points. The maximum optical path difference of the interferometer is about 1.5 m, giving a maximum theoretical resolution of 0.004 cm−1.
TL;DR: The use of combined gas-liquid chromatography and infrared spectroscopy (GC/IR) has seen a marked increase in interest in the use of GC/IR in the past few years.
Abstract: The past few years have seen a marked increase in interest in the use of combined gas-liquid chromatography and infrared spectroscopy (GC/IR). This increase in interest is primarily due to the advent of Fourier transform infrared spectroscopy (FTIR). The combination. GC/FTIR. provides the sensitivity and scanning speed which have hindered the wide applicability of GC/IR using dispersive instruments.
TL;DR: In this article, the functional groups present in solvent-refined coal samples were identified from their infrared spectrum using the group-frequency approach, using the infrared spectrum of the parent coal.
TL;DR: In this article, the Fourier transform infrared spectrum of atactic poly(methyl methacrylate) (PMMA) is compared with that of PMMA labeled with 18O in the ester groups.
Abstract: Fourier transform infrared spectrum of atactic poly(methyl methacrylate) (PMMA) is compared with that of atactic PMMA labeled with 18O in the ester groups. The results obtained define the assignment of the bands associated with vibrations of the ester groups of PMMA. Furthermore, the Fourier transform infrared spectroscopy provides a simple method for obtaining the spectra of "pure" derivatives containing 18O.
TL;DR: Comparison of adsorption from a static versus a flowing blood plasma system indicated that a greater amount of protein was adsorbed when thestatic system was employed, but desorption was observed with the static system and not in the flowing system.
Abstract: The adsorption of blood proteins onto various surfaces in contact with flowing blood plasma or serum has been investigated using Fourier Transform infrared spectroscopy (FT-IR) coupled with attenuated total reflection (ATR). Comparison of adsorption from a static versus a flowing blood plasma system indicated that a greater amount of protein was adsorbed when the static system was employed, but desorption was observed with the static system and not in the flowing system. When plasma and serum were compared in terms of amount and type of protein adsorbed, little difference was noted in either kinetics of adsorption or stability of the adosrbed layers. Variations in the ratios of infrared adsorption bands (from either plasma or serum) indicate that changes occur during the adsorption process in the protein layers. A comparison of poly(vinyl chloride) to germanium as the protein adsorbing surface in the static system showed differences in terms of the composition of the adsorbed layers.
TL;DR: In this paper, a numerical deconvolution procedure was used to produce amplitude-corrected, phasecorrected absorption-mode Fourier transform ion cyclotron resonance (FT ICR) spectra.
TL;DR: For spectral lines with combined Doppler and pressure broadening, the Fourier transform of the line shape is calculated analytically in an isothermal layer in which both the pressure and absorber concentrations vary along the line of sight.
Abstract: For spectral lines with combined Doppler and pressure broadening, the Fourier transform of the line shape is calculated analytically in an isothermal layer in which both the pressure and absorber concentrations vary along the line of sight. Use of the Cooley-Tukey fast Fourier transform algorithm allows efficient computation of the optical depth of such layers containing a large number of absorption lines of the same shape. The computation time is almost independent of the number of absorption lines. In many cases, this method allows increased speed and accuracy compared with conventional line-by-line methods.
TL;DR: In this paper, a multidimensional vector approach is used to form compound-specific vectors from the interferograms of mixture components, which are then compared with a set of known compound vectors by calculating how close together any two vectors lie in space.
Abstract: A compound identification system for gas chromatography/Fourier transform infrared spectroscopy data has been developed based on the direct comparison of interferograms. A multidimensional vector approach is used to form compound-specific vectors from the interferograms of mixture components. Comparisons are made with a set of known compound vectors by calculating how close together any two vectors lie in space. This system is used to identify the components of several synthetic mixtures.
TL;DR: In this paper, Fourier transform spectroscopy has been used for the characterisation of the excited state, B 1u, of an argon-ion laser in a complex spectrum.
Abstract: Fluorescence of 130Te2 and 128Te2 excited by lines of an argon-ion laser have been recorded by Fourier transform spectroscopy. The resolution and precision afforded by this technique has enabled several new features of this complex spectrum to be observed for the first time, including the characterisation of the excited state, B 1u. It is concluded that this is a method of some general utility.
TL;DR: In this article, conditions for reliable measurement of the power spectrum of opaque rough surfaces by direct optical Fourier transformation were determined and the relation of the spectrum of the surface irregularities to the optically observed spectrum was discussed and experimental results obtained to date with a transform apparatus were presented.
TL;DR: In this article, Fourier transform infrared spectroscopy (FT-IR) has been applied to the study of the molecular mechanisms of transitions of atactic polystyrene above Tg.
Abstract: Fourier transform infrared spectroscopy (FT-IR) has been applied to the study of the molecular mechanisms of transitions of atactic polystyrene above Tg. Intensity measurements of vibrational modes as a function of temperature revealed two transitions above Tg, which are designated as Tu and T′u. T′u is independent of molecular weight as opposed to the molecular weight dependent Tu whose behavior is similar to Tg. Infrared measurements are more sensitive to T′u than Tu. Conformationally sensitive bands show that T′u may be related to disruption of local order where there is a negligible barrier to conformational change.
Patent•
21 Dec 1979TL;DR: In this paper, an optical manifold permitting a single pumping source to be utilized to selectively pump a plurality of laser sources is presented. Switching of the emission from the pump source to the laser source is accomplished by a plurality OF FTIR switches.
Abstract: The invention relates to an optical manifold permitting a single pumping source to be utilized to selectively pump a plurality of laser sources. Switching of the emission from the pumping source to the laser source is accomplished by a plurality of FTIR switches. A second group of FTIR switches is utilized to switch the output beams of the laser sources to a common output path.
TL;DR: In this paper, the dependence of physicochemical properties on the pH of micellar solutions for N-(2-hydroxyethyl)-N-(2hydroxyalkyl)-β alanines (HAA) was studied by means of a differential titration method (DTM), Fourier transform infrared (FTIR) spectra, and measurements of critical micelle concentration, surface tension, and foaming power.
Abstract: The dependence of physicochemical properties on the pH of micellar solutions for N-(2-hydroxyethyl)-N-(2-hydroxyalkyl)-β alanines (HAA) was studied by means of a differential titration method (DTM), Fourier transform infrared (FTIR) spectra, and measurements of critical micelle concentration, surface tension, and foaming power. The aspect of the dissociation of HAA was pursued by DTM. The mutual transformation among cationic, zwitterionic, and anionic forms with the change of pH range was confirmed by FTIR spectroscopy. The micelle formation energy was determined at each pH value. Further, the dependence of surface active properties on the pH value for the adducts of ethylene oxide to Na-HAA was also investigated.