Microspectroscopy mapping techniqu

The so-called microspectroscopy mapping technique has been developed by attaching a microscope equipped with special reflecting-type optics and focal plane array detectors to FTIR spectrophotometers. 

FTIR microspectroscopy, coupled with mapping techniques, is an effective method for evaluating dimensionally-dependent changes. The method is based on the specificity of the IR spectrum and the dimensional resolution of the microscope. The keys to the successful use of FTIR microscopy are experience in sample preparation, an understanding of light microscopy, and ingenuity in defining solutions. 

Garcia et al [478 80] have used FTIR microspectroscopy and mapping techniques for outdoor photodegradation of PVC siding capstock formulations as a function of exposure time and Ti02 level. In this case advantage was taken of the complexity and specificity of the IR spectrum and the dimensional resolution of the microscope. CaCOs and acrylic impact modifier profiles for co-extruded... 

Infrared spectroscopy is well established, and infrared spectra are considered to be definitive for identity testing in the pharmaceutical industry. FTIR microspectroscopy, equipped with an automated stage, is a nondestructive technique that can be utilized to analyze small samples and to chemically map locations by identifying components within the sample. When unidentified crystalline particles were found growing on tablets during a stability study, FTIR microspectroscopy with a spectral resolution of about 5 pm was used to chemically analyze and identify the minute particles. 

FTIR microspectroscopy is a microanalytical technique, which interfaces an FTIR spectrometer to an optical microscope. Regions of interest in the sample are spatially isolated using the microscope s apertures. It enables the IR spectrum of sampling regions down to about 10 pm resolution to be taken. Consequently, FTIR microscopy is ideal for compositional mapping and analysis of heterogeneous samples whose domain sizes are in the tens of micrometre range. 

On-line/in-line technology for monitoring extrusion processes, including FTIR microscopy, near-IR spectroscopy and optical microscopy was reviewed [500]. Several reviews describe uFTIR applications to polymers [458,501]. Line map applications of /U.FTIR have been discussed [491]. A recent review [502] refers to a large number of FTIR mi-crospectroscopic studies as an important source of structural and spatial information for polymer-based articles. A monograph describes applications of FTIR microspectroscopy to polymers [393]. ASTM E 334 (1990) describes the general techniques of infrared microanalysis. 

A more recent development in this area is FTIR imaging. This technique is a powerful tool that can be used to study a range of polymer systems, including multilayer polymer films, composite materials, fibers, and blends [212]. By selecting the characteristic bands of a chemical species, its spatial distribution can be mapped. Conventional infrared microspectroscopy uses apertures to limit the examined area... 

Recently, IR microspectroscopy has been used to develop two-dimensional functional group images of polymer samples. A two-dimensional computer-restored step-scan was performed on the sample in order to obtain a compositional map. A 250 X 250 p.m aperture was used in 250-p.m steps in the x and y directions with the aid of a computer-controlled moving stage. Although the technique is powerful, it has two major disadvantages. The resolution is 3 to 10 times less than with Raman and fluorescence microbeam methods, and the time required for data collection and reduction can be as long as 24 h. 

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