Showing papers on "Fourier transform infrared spectroscopy published in 1984"
TL;DR: The 1000-1300 cm-1 region of the infrared spectrum of dipalmitoylphosphatidylcholine (DPPC) and other phosphate-containing molecules has been studied by the Fourier-transform technique, finding band-shifts toward higher wavenumbers.
143 citations
TL;DR: A Fourier transform spectrometer with no mechanical moving parts is described, which may be built in a relatively small size and with moderate cost and may lead to the application to time-resolved spectroscopy.
Abstract: A Fourier transform spectrometer with no mechanical moving parts is described. The interferogram is generated spatially by a triangle common-path interferometer and is detected by a self-scanning photodiode array. The spectrum is reconstructed by fast Fourier transform in a microcomputer system. Since no moving part is used and a common-path interferometer is employed for simple, stable, and easy alignment, this spectrometer may be built in a relatively small size and with moderate cost. The self-scanning photodiode array as a multichannel detector may lead this spectrometer to the application to time-resolved spectroscopy. The optical throughput is much larger than that of a multichannel dispersion-type spectrometer, because in the system neither a slit nor an aperture is necessary. The emission spectra of a low pressure mercury lamp and a LED are shown to demonstrate the system performance.
127 citations
TL;DR: In this article, Fourier transform infrared spectroscopy was used to study the adsorption of silane coupling agents on high-surface-area silica and E-glass fiber surfaces.
114 citations
01 Jan 1984
TL;DR: In this paper, the authors present the relevant instrumental and theoretical background of polymer deformation and relaxation studies by simultaneous FTIR spectroscopic and mechanical measurements and summarize selected experimental results obtained by this technique.
Abstract: The advantages of Fourier-Transform infrared (FTIR) spectroscopy over conventional dispersive instrumentation have revitalized the utilization of vibrational spectroscopy in polymer research. In the field of rheo-optics primarily the rapid-scanning capability of the FTIR technique has contributed to a more detailed insight into the technologically important process of polymer deformation. It is the purpose of this review to present the relevant instrumental and theoretical background of polymer deformation and relaxation studies by simultaneous FTIR spectroscopic and mechanical measurements and to summarize selected experimental results obtained by this technique.
105 citations
TL;DR: In this article, the authors show that in the monomolecular layer, adsorbed γ-methacryloxypropyltrimethoxysilane (γ-MPS) occupies a surface area of 0.59 nm2 per molecule and is oriented parallel to the surface.
84 citations
81 citations
TL;DR: In this article, the experimental considerations necessary to effect successful recording of in situ vibrational spectroscopy at the electrode-solution interface are described, and the Fourier transform infrared spectrometer is used.
78 citations
TL;DR: Observation d'une nouvelle bande Ramour a 1545 cm −1 au cours de la polymerisation radicalaire a 60°C du methacrylate de methyle.
Abstract: Observation d'une nouvelle bande Ramour a 1545 cm −1 au cours de la polymerisation radicalaire a 60°C du methacrylate de methyle
74 citations
TL;DR: In this paper, Fourier transform infrared (FTIR) spectroscopy is used to determine the cure rate of an epoxy resin consisting of Tetraglycidyl-4,4′-diaminodiphenyl methane (TGDDM) and diaminodiphoenylsulfone (DDS).
Abstract: Fourier transform infrared (FTIR) spectroscopy is used to determine the cure rate of an epoxy resin consisting of Tetraglycidyl-4,4′-diaminodiphenyl methane (TGDDM) and diaminodiphenylsulfone (DDS). Cure rates at 120 and 160°C are shown to increase noticeably when 1% BF3–MEA is added to either TGDDM to TGDDM plus DDS. Fluoroboric acid is shown to increase the cure rates even more than the BF3–MEA. These Results combined with the NMR results in the accompanying article indicate that BF3–MEA is not a catalyst for epoxy resin cure. Instead it is rapidly hydrolyzed to fluoroboric acid which acts as the catalyst.
74 citations
TL;DR: In this article, Fourier transform infrared spectroscopy has been used to characterize the crosslinking of polyimide materials using maleimide and amine absorption bands, and the residual amount of double bonds present in the cured material is a function of the temperature.
Abstract: Interesting polyimide materials, possessing good mechanical and thermal properties, are obtained by homopolymerization or reaction of 4,′4-bis(maleimidodiphenylmethane) with a diamine. Fourier transform infrared spectroscopy has been used to characterize the crosslinking of such materials using maleimide and amine absorption bands. Amine group reaction on double bonds is readily achieved and appears to be insensitive to the temperature of curing. On the other hand, the decrease of maleimide double bonds is strongly dependent on the reaction temperature. The residual amount of double bonds present in the cured material is a function of the temperature: a linear relationship holds between residual double bond concentration vs. curing temperature. The general behavior during crosslinking of this kind of polyimide was related to glass transition temperature changes.
67 citations
TL;DR: In this paper, the Fourier coefficients computed from the NIR spectra of pulverized tobacco samples can be used to estimate certain chemical constituents in the samples, which can reduce the computation time for calibration by 96% and reduce the magnetic storage space requirements by 98%.
Abstract: Fourier coefficients computed from the NIR spectra of pulverized tobacco samples can be used to estimate certain chemical constituents in the samples. As few as 11 coefficients from the Fourier domain used in a stepwise multiple linear regression (SMLR) model provide results equivalent to a 7-term SMLR model using log I/R from the wavelength domain. The Fourier model reduces the computation time for calibration by 96% compared to the wavelength model, and reduces the magnetic storage space requirements by 98%. Removing the mean term from the Fourier model partially corrects the particle size anomaly encountered in pulverized samples.
TL;DR: In this paper, the molecular structure of γ-methacryloxypropyltrimethoxysilane (γ-MPS) was modeled by adjusting the pH of an aqueous alcoholic solution of the silane in absence of a substrate.
Abstract: The molecular structure of γ-methacryloxypropyltrimethoxysilane (γ-MPS) deposited on the surfaces of particulate mineral fillers was modeled by adjusting the pH of an aqueous alcoholic solution of the silane in absence of a substrate. Hydrolyzates obtained from the solution were studied by gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FT-IR) and found to be polymethacryloxypropylsilsesquioxanes whose configuration and molecular-weight distribution were dependent on the solution pH. In acidic environments (below pH 4) the polycondensation mechanism appeared to proceed in a selective manner to form polycyclic blocks which resemble a beaded chain following condensation between blocks. Under more neutral and basic conditions (at or above pH 4) the polycondensation mechanism, resulted in polymethacryloxypropylsilsesquioxanes with the more equilibrated double chain ladder configuration. The molecular weight distribution of these structures was dependent on the stability of the silanol or the silanolate ion. Extremely high-molecular-weight and polydisperse polymethacryloxypropylsilsesquioxanes were generated at near neutral pH due to the formation of the double chain ladder configuration and the high silanol instability in this pH range. The two different polymethacryloxypropylsilsesquioxane configurations were also observed on γ-MPS modified metal oxide substrates. The structures help explain some of the previously observed trends with respect to γ-MPS adsorption on particulate mineral fillers. In strongly basic environments the methacrylate function of γ-MPS partially hydrolyzes to form sodium carboxylate, and carbon dioxide is absorbed from the air and reacts to form sodium carbonate.
01 Jan 1984
TL;DR: In this article, a review of the theory and application of Fourier transform infrared spectroscopy to the characterization of polymers is presented, where the basic theory, sampling techniques and spectral operations are described.
Abstract: This review covers the theory and application of Fourier transform infrared spectroscopy to the characterization of polymers. The basic theory, the sampling techniques and the spectral operations are described. The applications discussed include the study of polymer reactions, polymer structure and dynamic effects.
TL;DR: Fourier self-deconvolution of Fourier transform infrared (FTIR) spectra and second derivative FTIR spectroscopy were applied to study solvent-induced conformational changes in globular proteins to identify new conformation changes in beta-lactoglobulin and isopropanol-d1 solution.
TL;DR: In this article, the Fourier transform infrared (FTIR) spectra of electrochemically prepared polythienylene films doped with various dopant species at varying doping levels have been obtained.
TL;DR: The feasibility of a new technique, supercritical fluid chromatography/Fourier transform infrared spectrometry (SFC/FTIR), for separation and identification of nonvolatile and labile compounds in complex mixtures is discussed in this article.
Abstract: The feasibility of a new technique, supercritical fluid chromatography/Fourier transform infrared spectrometry (SFC/FTIR), for separation and identification of nonvolatile and labile compounds in complex mixtures is discussed in this report. The design of a high pressure (flow cell) interface is described. The results of a continuing study of possible mobile phases for SFC/FTIR are presented. Finally, SFC/FTIR was applied to a standard test mixture. The current detection limits of one component of the mixture, 2,6-di-t-butylphenol, are presented.
TL;DR: In this article, the extinction coefficients of the methyl deformation bands were determined for various branch types on the basis of 13C NMR data and the values changed from 0.39 to 0.76 depending on the type of branch.
Abstract: Qualitative and quantitative analysis of short chain branches was carried out on a series of low-density polyethylenes by Fourier transform infrared spectroscopy. The peak position of the methyl symmetrical deformation bands around 1378 cm−1 was found to vary with the type of branches and used for identification of the branch type in low-density polyethylenes. The reciprocals of extinction coefficients of the methyl deformation bands were determined for various branch types on the basis of 13C NMR data. The values changed from 0.39 to 0.76 depending on the type of branch. The methyl rocking bands ranging from 880 to 940 cm−1 were examined using brominated samples. The peak positions also depended on the type of branch. For the methylene rocking bands, the peak at 772.2 cm−1 due to the ethyl branch was clearly observed, but that due to the n-butyl branch was not detected around 745 cm−1, indicating the n-butyl absorption to be located very close to 730 cm−1 rather than 745 cm−1.
TL;DR: In this paper, FT-IR spectra obtained as a function of time revealed many changes in spectral content, providing new information about anomer characteristic bands in aqueous media.
Abstract: FT-IR spectral investigations on carbohydrates were undertaken in aqueous media in order to facilitate the assignments of vibrational bands. For pure anomeric forms of glucose, FT-IR spectra obtained as a function of time revealed many changes in spectral content, providing new information about anomer characteristic bands in aqueous media. It was also found that fructose, which is known to undergo complex mutarotation, exhibits two types of spectral changes, whereas glucose, which undergoes simple mutarotation, shows a single type of spectral change. Thus FT-IR spectral investigations in aqueous carbohydrates should be able to distinguish between simple and complex mutarotation cases. As a vibrational spectroscopic technique, the importance of FT-IR spectroscopy is further emphasized by showing that Raman spectroscopy is not sensitive enough to reveal the structural changes of carbohydrates in aqueous media.
TL;DR: Comparison of the Schiff base regions of the K Raman and FTIR spectra provide additional information on the assignment of its Schiff base vibration and the unexpected similarity between the resonance Raman scattering intensities and the FTIR absorption intensities for BR and K is discussed.
Abstract: —Fourier transform infrared (FTIR) difference spectra of the BRrK transition in bacteriorhodopsin at 77K are compared with analogous resonance Raman difference spectra obtained using a spinning sample cell at 77K. The vibrational frequencies observed in the FTIR spectra of native purple membrane and of purple membrane regenerated with 15-deuterioretinal are in good agreement with the frequencies observed in the Raman spectra, indicating that the lines in the FTIR difference spectra arise predominantly from retinal chromophore vibrations. This agreement confirms that the spinning cell method for obtaining resonance Raman spectra of K minimizes potential contributions from unwanted photoproducts. The unexpected similarity between the resonance Raman scattering intensities and the FTIR absorption intensities for BR and K is discussed in terms of the delocalized electronic structure of the chromophore. Finally, comparison of the Schiff base regions of the K Raman and FTIR spectra provide additional information on the assignment of its Schiff base vibration.
TL;DR: In this article, detailed information about three new singlet gerade states has been obtained, one of which, (3s, 4s)1 Sigma g+, is known to be involved in optically pumped infrared lasing transitions.
Abstract: Ultraviolet lines of krypton-ion and argon-ion lasers have been used to excite infrared fluorescence in Na2 which has been recorded at high resolution by Fourier transform spectroscopy. Detailed information about three new singlet gerade states has been obtained, one of which, (3s, 4s)1 Sigma g+, is known to be involved in optically pumped infrared lasing transitions. Constants for the states are given.
TL;DR: In this article, a cell and optical configuration for measuring diffuse reflectance Fourier transform infrared spectra of adsorbed species at high sensitivity are described, where the cell may be heated to 600 °C and evacuated to 10 −6 torr, permitting activation and treatment of catalysts and adsorbents in situ.
TL;DR: The amide I bands of fibrinogen adsorbed on the metal surfaces shift towards higher frequencies relative to the same band in buffer solution, which indicates that conformational change of the protein occurs upon adsorption on metal surfaces.
TL;DR: In this paper, the authors report FT-IR-VCD recorded under improved conditions of signal-to-noise ratio, resolution, and spectral range (to 800 cm−1).
Abstract: We report FT-IR-VCD recorded under improved conditions of signal-to-noise ratio, resolution, and spectral range (to 800 cm−1). Detailed descriptions are provided in the areas of artifact suppression, phase correction procedures, and comparison of FT-IR to dispersive VCD measurements. Spectral evidence supports the proposition that VCD absorbance artifacts are a surface effect originating at the optical window–solution interface.
TL;DR: Analyse par les deux methodes de Biomer et Avcothane, deux melanges commerciaux biocompatibles et de leurs constituants homopolymer.
Abstract: Analyse par les deux methodes de Biomer et Avcothane, deux melanges commerciaux biocompatibles et de leurs constituants homopolymer
TL;DR: In this article, the onset, progress and decay of strain-induced crystallization in loading-unloading cycles of sulfur-crosslinked natural rubber at 300 K and 343 K were monitored.
Abstract: Rheo-optical FTIR spectroscopy has been applied to monitor the onset, progress and decay of strain-induced crystallization in loading-unloading cycles of sulfur-crosslinked natural rubber at 300 K and 343 K. From the short-time spectroscopic data conclusions were also drawn with respect to the orientation of the average polymer and the polymer chains in the strain-induced crystal phase.
IBM1
TL;DR: In this article, a liquid analyzer was used for infrared spectroscopy of aqueous solutions of penicillin VK, sodium oxacillin and sodium methicillin.
Abstract: Infrared spectra of aqueous antibiotic solutions were obtained using a new Liquid Analyzer accessory in a Fourier transform infrared (FT-IR) spectrometer. Based on a cylindrical internal reflectance element, the Liquid Analyzer accessory provides a sufficiently short (~0.015 mm) effective pathlength for infrared spectroscopy of aqueous solutions from 3200 to 800 cm−1. Spectra of aqueous solutions of penicillin VK, sodium oxacillin and sodium methicillin are shown. By measuring the absorbance of the beta-lactam carbonyl band, FT-IR spectroscopy with the accessory exhibits analytical sensitivity to less than 0.1% concentration by weight of antibiotic both in aqueous solution and in an actual fermentation broth.
TL;DR: In this paper, Fourier transform infrared spectroscopy was applied to the analysis of the strutural changes which occur within the lipid bilayer as the temperature is varied, providing the basis for the interpretation of phase transitions in complex biomembranes.
TL;DR: In this article, the authors measured the infrared emission spectra of thin polymer layers on flat aluminum plate using Fourier transform infrared spectrometry (FT-IR-EMS) and found that the detection limit was comparable with that of FT-IR RAS when an emission ray was collected at a viewing angle of 70°.
Abstract: Infrared emission spectra of thin polymer layers on flat aluminum plate have been measured using Fourier transform infrared spectrometry. The detection limit of Fourier transform infrared emission spectrometry (FT-IR-EMS) was found to be comparable with that of Fourier transform infrared reflection absorption spectrometry (FT-IR-RAS) when an emission ray was collected at a viewing angle of 70°. The merits of FT-IR-EMS over FT-IR-RAS were demonstrated in the measurement of nonflat surfaces. The residual lubricant on steel tire cords could be detected efficiently by the FT-IR-EMS mode. The linear relationship found between the relative emission intensity and the thickness of film represents the possibility for a quantitative analysis of a thin overlayer on metal surface.
TL;DR: Weakly bound BF 3 with CO and with N 2 have been obtained by controlled condensation of a gaseous mixture on a cold CsI window and characterized by FTIR spectroscopy.