Aluminum film, reflection spectrum

The interaction between these films and bulk epoxy resin was assessed by immersing an aluminum mirror coated with an air-dried primer film in a Petri dish filled with the epoxy resin, heating the dish in an oven at 100°C for 1 h, allowing the dish to cool overnight, and then extracting any unreacted material from the surface of the mirror by MEK extraction. Figure 6A is the reflection spectrum of a relatively thick film (ca. 3 / n) of neat DGEBA resin (cast onto polished aluminum from a 3% solution in toluene), and Fig. 6B shows the RAIR spectrum obtained from the mirror that was primed, heated in resin, and extracted. The... 

Figure 3. Reflection spectrum of an oxidized aluminum film exposed to 0.010M acetic acid in ethanol also shown are the 1ETS peak positions (13)...

Figure 8.17 shows the visible image of the laser-induced grid on the aluminum-metalized PET film (the dark lines indicate the PET) and the corresponding FT-IR/ATR image based on the PET-specific v(C=0) band. Figure 8.18 shows FT-IR/ATR spectra of an exposed (irradiated) PET area (red) and of an aluminum-coated (nonirradiated) area (blue) this spectrum clearly shows the dispersion-shaped features of a reflection spectrum. 

Figure 3. External reflection IR spectrum of an 10-A film of poly (acrylic acid) on native-oxide-covered, evaporated aluminum. The jagged line is the unsmoothed spectrum at 2 cm 1 resolution. The major peak assignments are 1740 cm 1, unionized carboxylic acid, C = O stretch and 1620 cm 1, the carboxylate ion asymmetric stretch 1475 cm 1, CH2 bending. (Reproduced, with permission, from Ref.

Mirabella and Koberstein have previously shown the benefit of DSC/FT-IR for polymer characterization (3,4). In this work, the same epoxy system described above in the uncured state was analyzed by DSC/FT-IR. Thin films of uncured amine-activated epoxies were placed in the sample pan of the FP84 and heated from 25 to 280 °C at 10 C per minute. Changes in the structure of the epoxy as a fimction of temperature were recorded simultaneously by infrared spectroscopy. The sample was relatively transmissive to infirared radiation. The beam transmitted down through the sample, reflected off the aluminum cup, and passed back up through the material. This type of analysis is called reflection/absorption spectroscopy. A "well behaved" absorbance spectrum was generated directly without any need for correction. To produce a sufficient signal on the DSC, the bulk of the sample had to be placed on the reference side. 

The first commercially successful off-line DD-HPLC/FT-IR interface was the LC Transform, made by Lab Connections [41]. With this device, nebulization is initiated ultrasonicaUy and the solvent is evaporated with either a thermospray or a concentric flow nebulizer. The solutes are first deposited on a rotating germanium disk on the underside of which a thick layer of aluminum has been deposited. After the deposition step, the disk is then moved to a specular reflection accessory that is mounted in the sample compartment of a standard FT-IR spectrometer. The developers of the LC Transform recognized that it is more convenient to measure the spectra of the components that had been deposited on the disk by reflection spectrometry than by transmission. However, the deposition of a very thin film of each eluate on a metal substrate would not allow its reflection-absorption spectrum to be measured with adequate efficiency without resorting to grazing incidence measurements, for which the disadvantages were discussed in Section 23.3.3. 

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