FTIR-ATR Measurements

Because the conversion of the C=0 group in benzophenone leads to the loss of conjugation between the carbonyl group and the aromatic ring upon UV ex- 

In order to evaluate these two effects on the kinetic profile of UV-crosslink-able acrylic PSA, the relative concentration of C=C in the benzophenone was calculated by integrating the peak area between 1577 and 1604 cm .  

In Fig. 17.4, the influence of the composition of the benzophenone is shown. The relative contents of the C=C in the benzophenone of SH3P2 were lower than those for SH3P1 at a UV dose of 210 mJ cm . This effect may be due to the higher content of benzophenone in PSA, which increased the efficiency of 

UV curing at low UV doses. But at UV doses above 630 mj cm, the relative C=C contents were almost the same. This may be due to the increased cross-linking density, which reduced the mobility in the PSAs. This phenomenon confirmed the result of many previous studies, that the maximum UV-curing rate was shifted to an earlier stage of UV irradiation when the photoinitiator content was increased. After this point, however, the increased crosslinking density reduced the molecular mobility and so the curing rate decreased [15-17]. 

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The aim of this report is to present the results of the experimental work done recently in our laboratories to study both the surface and the bulk mebrane processes to demonstrate the importance of one over the other in the potential response function. The short time behaviour of model membranes was studied by response time measurements, while the transport processes within the membranes were followed under in situ conditions by means of FTIR-ATR-spectrometry and ion-chromatography. In situ conditions means that the membranes remained in contact with aqueous K" "-containing solutions throughout the FTIR-ATR-measurements simulating normal operating conditions of the electrode membranes. Prior to... 

FTIR-ATR measurement was performed on nanofiber mats of pure PVAc and its nanocomposites. The spectra were collected from all nanofiber samples that were compared to PVAc. 

Another label-free optical detection method—FTIR-ATR—has been applied for detection of thrombin by means of DNA aptamers [73], The antithrombin DNA aptamer previously developed by Tasset et al. [17] was immobilized covalently onto Si surface using UV irradiation method. As a quantitative measure, the area of N-H and CH2 bands was used. This method allowed to detect thrombin with a sensitivity around 10 nmol/L. The specificity of binding of protein to aptamer was also investigated using DNA with no binding site for thrombin. It has been noted that for effective binding study by FTIR-ATR method, the concentration of protein should be kept lower than 100 nmol/L. 

S. Banerjee, R.P. Semwal and S. Agarwal, Measurement of diffusivities of sulfur mustard (SM) and its analog oxygen mustard (OM) in cured butyl, nitrile, and natural-rubber sheets by weight-gain and FTIR-ATR methods, J. Appl. Polym. Sci., 57, 1483-1490 (1995). 

A report is presented on the fluorination of the inner surface of blood circulating tubes made from PVC using APG discharge treatment in order to enhance biocompatibility and suppress the bleeding of plasticisers from the PVC. A hydrophobic surface was produced on the inner surface of the tube by polymerising hexafluoropropylene or tetrafluoroethylene and the treated surfaces analysed by X-ray photoelectron spectroscopy, FTIR-ATR spectroscopy and contact angle measurements. 17 refs. 

To date, there have been no published studies using ATR-FTIR to measure the spectra of just the protein in (bulk) solution. We have found that such solution spectra can be obtained by subtracting the contribution of denatured material irreversibly bound to the IRE surface from that of bulk and adsorbed protein. The strong interactions between polypeptides and IRE materials that immobilize proteins on IRE surfaces have a deleterious effect on the structure of these molecules. The characteristics of the adsorption process and its affects on protein structure will be discussed elsewhere (10). 

In the case of PVC/PHMA system, the graded structures of the samples could not be examined by FTIR-ATR and DSC methods, because PHMA was very soft at r.t. and that DSC curve did not indicate clear change around Tg. Thus, the graded structure was measured by SEM-EDX method(Fig. 5). The chlorine content in the sample increased gradually towards the petri glass side, and then it is considered to have wide graded structure. 

The oxidation of cycloalkanes or alkylarenes with molecular oxygen and acetaldehyde as a co-reductant takes place efficiently in scC02 under mild conditions. No catalyst is required and high-pressure ATR-FTIR online measurements showed that a radical reaction pathway was heterogeneously initiated by the stainless steel of the reactor walls (Equation 4.34) [67]. 

Zeolite membranes are commonly characterized by SEM, XRD. TEM, EPMA, SEM-EDX, TEM-EOS, and Nitrogen adsorption are also used to study the morphology, microstructure and composition of zeolite membranes. Usually single gas permeation, mixed gas separation, pervaporation and vapor permeation are performed to evaluate the properties of zeolite membranes. Recently, some novel characterization techniques have been applied. Infrared reflectance measurement was used to characterize membrane thickness [19]. Fluorescence confocal optical microscopy was used to image the grain boundary structure of zeolite membranes [20]. FTIR-ATR method was used to characterize the T-O vibration of zeolite membranes [21],... 

The construction of a cell permitting both FTIR measurements and electrochemical impedance measurements at buried polymer/metal interfaces has been described [266]. Ingress of water and electrolyte, oxidation (corrosion) of the aluminum metal layer, swelling of the polymer and delamination of the polymer were observed. A cell suitable for ATR measurements up to 80°C has been described [267]. The combination of a cell for ATR measurements with DBMS (see Sect. 5.8.1) has been developed [268]. It permits simultaneous detection of stable adsorbed species and relatively stable adsorbed reaction intermediates (via FTIR spectroscopy), quantitative determination of volatile species with DBMS and elucidation of overall reaction kinetics. An arrangement with a gas-fed electrode attached to the ATR element and operated at T = 60°C has been reported [269]. In this study, the establishment of mixed potentials at an oxygen consuming direct methanol fuel cell in the presence of methanol at the cathode was investigated. With infrared spec-... 

The experimental set-up used in connection with FTIR-ATR-spectrometry enabled us to follow the dilfusion of the components of interest through the membrane under realistic conditions for ISFETs. One side of the membrane is in contact with a solid state electrode the other side with the aqueous solution containing the ion to be determined. This means that the membrane being analysed remains in contact with the solution throughout the whole measurement rather than being separated and dried. This set-up allows an investigation of the diffusion process in model membranes and a direct comparison of the results with the electrochemically measured time dependent parameters of the corresponding electrodes. 

Thick Membranes (1 pm< d <10 pm). The thick film case (according to Fig.lb) is markedly different from the case of thin film because the transport of SCN -ions with the K-crown-ether complex can clearly be observed by the FTIR-ATR-technique. The increase of the intensity of the zz-SCN band within 30 min after the first contact between the 0.5 mol/1 solution of KSCN and the membrane can be measured from Fig.3 and is displayed in Fig.4 (crown ether curve). A comparison of the analogous curve with the dummy membrane shows that even a low content of crown ether in the membrane (2 %) significantly increases the SCN-amount extracted into the membrane. When the concentration of KSCN in the bathing solution was increased a further increase in the amount extracted was observed by... 

FTIR-ATR spectroscopic measurements were performed on PVAc and its nanocomposites. The spectra collected from nanofiber samples were almost identical to that of PVAc and not much changes observed. 

The chemical polymerization of Py by CAN in PU solutions leads to the formation of PU/PPy composites. The composites were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR], dynamic mechanical analysis (DMA], thermal gravimetric analysis (TGA], differential scanning calorimetry (DSC], X-ray photoelectron spectroscopy (XPS], and SEM measurements. The absorbances of the disordered H-bonded urethane carbonyl decrease with increasing Py concentration. The fraction of the hydrogen-bonded carbonyls is increased and the melting point increases with the increase of PPy content. These indicate the incorporation of PPy into PU may cause the complex due to the intermolecular interaction between the PPy and PU. SEM images of composite nanofibers show good distribution of the second component and the composite solution is proper to form conductive composite nanofibers. 

New York City, 2nd-6th May 1999, p.2502-6. 012 MEASURING THE DIFFUSIVITY OF ADDITIVES IN POLYMER FILMS USING IN SITU FTIR-ATR SPECTROSCOPY Gaghardi C A. Muire L B Hirt D E Clemson,University (SPE)... 

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