Microscopy techniques listed

It is necessary to use a combination of microscopy techniques to cover the relevant length scales of a heterogeneous structured product. A number of microscopy techniques are listed in Table 5.2. Even if the focus is on the micro- and nanoscales, it is wise to start a structure characterization on... 

Jaffe melted and isothermally recrystallized fibers spun under different stress levels. The bulk crystallization kinetics was measured with both DSC and optical microscopy techniques. Table 3.30 lists the samples studied. The film samples were included to ensure the absence of spurious DSC effects due to fiber packing. The samples were heated from 50°C to the melt temperature at 80°C/min. The melt temperatures ranged from 170 to 230°C. The samples were held in the melt for a specified time and then cooled to the 130°C crystallization temperature at 40°C/min. 

The physical and chemical techniques listed in Table 8-2 provide detailed structural information that can help understand some aspects related to the polymerization and crystallization of polysaccharides. They are complementary and it is actually not possible to have a complete structural characterization of a given polymer by using only one of these techniques. Other methods based on transmission electron microscopy examinations and involving cellulases coupled... 

The various general microscopy techniques are listed and compared in Tables 7.6 and 7.7. Table 7.6 compares optical, electron and scanning probe microscope techniques, with the magnification, resolution, field of view and imaging... 

In comparison with other microscopy techniques such as optical microscopy or scanning electron microscopy, SPM offers a number of advantages in terms of resolution and magnification. However, due to image acquisition by raster scanning, the measurement is slower and the maximum image size is generally smaller as well. Table 1 list some of the more common applications for SPMs. 

Before presenting the main microscopy techniques employed to determine membrane morphology, it is worth listing and briefly describing the membrane morphological parameters normally measured. 

The first step in the selection of a microscopy technique is to know the size of the polymer structures to be characterized. In fundamental studies, the answer might be that all of the structures present must be understood, whereas in more routine studies, a specific structure must be evaluated as part of the problem solving process. An example of a specific structure that is often evaluated is the spherulite. Spherulite sizes in semicrystalline polymers often determine the properties of the material. Monitoring this structure can be important in structure-property determinations. A listing of the most common polymer structure types, described in Chapter 1, and their characteristic sizes are shown in Table 7.2. Clearly, different microscopy techniques must be used to characterize these different structures. 

There are a lot of specific techniques that provide valuable information related to polymeric adhesives characterization. The more commonly used microscopy techniques are listed in O Table 43.2, including some figures about size ranges and magnifications. Every microstruc-tural characteristic is related to the overall mechanical behavior of the adhesive, and the use of all or some of these techniques can help in the postfracture analysis of the joints. 

Table 2.7 lists techniques used to characterise carbon-blacks. Analysis of CB in rubber vulcanisates requires recovery of CB by digestion of the matrix followed by filtration, or by nonoxidative pyrolysis. Dispersion of CB within rubber products is usually assessed by the Cabot dispersion test, or by means of TEM. Kruse [46] has reviewed rubber microscopy, including the determination of the microstructure of CB in rubber compounds and vulcanisates and their qualitative and quantitative determination. Analysis of free CB features measurements of (i) particulate and aggregate size (SEM, TEM, XRD, AFM, STM) (ii) total surface area according to the BET method (ISO 4652), iodine adsorption (ISO 1304) or cetyltrimethylammonium bromide (CTAB) adsorption (ASTM D 3765) and (iii) external surface area, according to the dibutylphthalate (DBP) test (ASTM D 2414). TGA is an excellent technique for the quantification of CB in rubbers. However, it is very limited in being able to distinguish the different types of... 

This chapter reviews the various methods used to identify and characterize iron oxides. Most of these are non-destructive, i. e. the oxide remains unaltered while being examined. These methods involve spectroscopy, diffractometry, magnetometry and microscopy. Other methods, such as dissolution and thermal analysis destroy the sample being examined. Only the principle of each method is given here. The main weight is put on the information about Fe oxides which can be extracted from the analytical results obtained by the different techniques together with references to relevant studies. A detailed description of each technique can be found in the appropriate texts listed in each section. 

Once the sample preparation is complete, the analysis is carried out by an instrument of choice. A variety of instruments are used for different types of analysis, depending on the information to be acquired for example, chromatography for organic analysis, atomic spectroscopy for metal analysis, capillary electrophoresis for DNA sequencing, and electron microscopy for small structures. Common analytical instrumentation and the sample preparation associated with them are listed in Table 1.1. The sample preparation depends on the analytical techniques to be employed and their capabilities. For instance, only a few microliters can be injected into a gas chromatograph. So in the example of the analysis of pesticides in fish liver, the ultimate product is a solution of a few microliters that can be injected into a gas chromatograph. Sampling, sample preservation, and sample preparation are... 

One objective of a kinetic analysis is to identify which, if any, of the rate equations (in an appropriate form) from Table 3.3. provides the most acceptable description of the experimental a, tor a, T data. In deciding what constitutes an "acceptable description", there are at least two main aspects to be considered (i) the purely mathematical "fit" of the experimental data to the relationship between a and t, (da/dt) and t or (da/d/) and a, required by the models listed in Table 3.3., together with the range of a across which this expression satisfactorily represents the data (whether the fit varies with temperature is also important) and (ii) the evidence in support of a kinetic model obtained by complementary techniques such as optical and electron microscopy, spectroscopy etc. (see Chapter 6). 

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