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Staining methods osmium tetroxide method

Fig. 3. Bpoxy heterogeneities as a function of amine curing agent content determined by two different methods. The upper series were microtomed samples stained with osmium tetroxide and the lower series were plasma treated fracture surfaces. Both methods gave size and distribution values for the heterogeneities which agreed qualitatively... Fig. 3. Bpoxy heterogeneities as a function of amine curing agent content determined by two different methods. The upper series were microtomed samples stained with osmium tetroxide and the lower series were plasma treated fracture surfaces. Both methods gave size and distribution values for the heterogeneities which agreed qualitatively...
Methods. Thin films of block copolymers were cast from their cyclohexane solutions at 20°C, and the films were observed under a polarizing microscope. Ultra thin films (50-500 nm) were cast from the same solutions onto sheet meshes at 20 °C and stained by osmium tetroxide vapor they were then observed under a Hitachi HU-11 electron microscope. [Pg.285]

A powerful method of examining the morphology of many multicomponent polymer materials utilizes transmission electron microscopy [Woodward, 1989]. If the two phases are nearly equal in electron density, staining with osmium tetroxide or other agents can be used. For more detailed discussion on the methods of morphology characterization, see Chapter 8. [Pg.422]

A new photoconversion method for TEM immunolabeling promises, at least in certain cases, to reduce these problems of penetration and local accessibility. This method is based on the generation of free radicals by excitation of the fluorochrome the oxidation of diaminobenzidine (DAB) by these free radicals generates precipitates that are converted to an electron-dense stain by osmium tetroxide (Deerinck et al., 1994). The ultimate resolution of this method should be determined by the diffusion of the free radicals prior to reaction with DAB and the size of the precipitate initial results indicate resolution comparable to immunogold methods (Deerinck et ai, 1994 Huang et al., 1994), although a detailed comparison of the sensitivity of the photoconversion method has not yet been done. [Pg.108]

The simplest method of polyblending involves equipment such as rolls or extruders, which can effect the mechanical blending of the two polymeric components in the molten state (Matsuo, 1968). High-impact polystyrene (HiPS) is an important example of a polyblend made by this technique. Such materials commonly contain 5-20 % of rubber, usually polybutadiene, dispersed in a polystyrene matrix. As shown in Figure 3.1, electron microscopy studies on specimens stained with osmium tetroxide reveal well-defined, irregular rubber particles (1-10 fim in diameter) dispersed in the polystyrene matrix. The elastomer domains appear dark because the osmium tetroxide stains the elastomer preferentially (see Section 2.4). [Pg.78]

Many of the studies of multiphase polymers are conducted on unsaturated rubbers which are adequately stained by osmium tetroxide, which reveals the nature of the dispersed phase domains. Polymers with activated aromatic groups have been selectively stained by reaction with mercuric trifluoroacetate (Section 4.4.8). Hobbs [262] has successfully used this technique to provide contrast in blends of poIy(2,6-dimethyl-l,4-phenylene oxide) and Kraton G (SBS block copolymer). Although this stain is effective in enhancing contrast, a drawback of the method is that the material is not hardened or fixed by the stain. [Pg.239]

A TEM study of poly(vinyl chloride)/chlori-nated polyethylene (PVC/CPE) assessed the dispersed phase morphology for correlation with impact properties [342]. Microtomed sections of the blend were stained by a two stage osmium tetroxide method to reveal the CPE phase [343] as the concentration increased, the discrete two phase morphology changed to a continuous network resulting in a transition from brittle to ductile impact fracture (shown... [Pg.328]

The Smith technique consisted of fixing the smear in osmium tetroxide vapor, immersion in HCI, mordanting in dilute formaldehyde, and staining with aqueous basic fuchsin. The method was said to possess certain advantages over the procedure of Robinow. [Pg.93]

This produces a brown end product which is highly insoluble in alcohol and other organic solvents. Oxidation of DAB also causes polymerization, resulting in the ability to react with osmium tetroxide, and thus increasing its staining intensity and electron density. Of the several metals and methods used to intensify the optical density of polymerized DAB, gold chloride in combination with silver sulfide appears to be the most successful (6). DAB has been classified as a potential carcinogen and therefore should be handled and disposed of with appropriate care. [Pg.17]

Several methods of studies have been developed. Osmium-staining technique, pioneered by Kato [1967], is one of the most successful methods for observing crazing in rubber toughened plastics. It depends upon a reaction between osmium tetroxide, OsO, and double bonds in PBD and other unsaturated polymers. However, it is not suitable for saturated rubbers. [Pg.885]

The staining technique for TEM uses a material that absorbs electrons and preferentially attaches itself to or reacts with certain regions of the polymer rather than other regions. Materials frequently used are uranyl acetate and osmium tetroxide. For polyethylene the technique of chloro-sulphonation can be used. In this method, which involves immersing the sample in chlorosulphonic acid, the electron-absorbing material becomes attached to lamellar surfaces, so that lamellae (see section 3.4.2) with their planes parallel to the direction of the electron beam become outlined in black in the micrographs. [Pg.59]

Electron Microscopy The sample preparation was based on Kato s (10) osmium tetroxide staining technique and a two-step sectioning method. The specimens were exposed to O5O4 vapor and cut with a LKB ultratome III to get a 0.1 y slice. The electron micrographs were taken with an AEI 6B and a Phillips 300 transmitting electron microscope with a magnification of 95,000. [Pg.187]


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See also in sourсe #XX -- [ Pg.95 , Pg.96 , Pg.97 , Pg.98 , Pg.99 ]




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