Micrographs microscopy Transmission electron

Transmission electron microscopy micrographs (Fig. 13.24) also indicate an important characteristic of the supported particles. As in the case of suspensions, they are either aggregated or isolated. Support surface properties may he an important factor governing this aggregation. After deposition on the support, we observed that samples prepared from acidic hydrosols are characterized by the presence of aggregated particles constituting flocculates ranging from 10 to 200 nm, whereas samples prepared via basic hydrosols contain only isolated particles. The opposite was observed when hydrosols were concerned. These final states of the supported particles may be controlled... 

Fig. 6.22 Bright-field transmission electron microscopy micrograph showing the presence of a SiC nanoparticle located in a multigrain pocket (arrow) [57]. With kind permission of John Wiley and Sons...

Fig. 2. (a) Transmission electron microscopy and (b) high resolution transmission electron microscopy micrographs of NTR sample thin foil obtained using FBB. 

Figure 4.14. Transmission electron microscopy micrographs of longitudinally sectioned PET fibers taken before (A) and after (B) isoprene inclusion and staining reveal major differences. The untreated fiber exhibits no structural detail and aggregated particles and holes within the aggregates. After treatment, dense regions of stained isoprene are observed adjacent to the particle aggregates, confirming that these regions were originally holes in the fiber, about lOnm wide.

Figure 4.15. Transmission electron microscopy micrographs of a sectioned microporous membrane show little detail of the structure due to the low electron scattering of the polymer (A). Treatment with an unsaturated surfactant followed by osmium staining results in sections with enhanced contrast, which permits...

Figure 4.19. Transmission electron microscopy micrograph of a chlorosulfonic acid stained linear polyethylene crystallized isothermally from the melt reveals the electron dense interlcimellar surfaces typical of polyethylene.

Figure 4.21. Transmission electron microscopy micrographs of latex particles are shown images taken in a microscope with a cold stage (A) and after both staining with PTA and using the cold stage (B). (From Shaffer [274] unpublished.)...

Figure 4.22. Transmission electron microscopy micrographs of sectioned industrial tire cords are prepared by the ebonite method to enhance the contrast of the various structures and to harden the adhesive and the rubber for sectioning. Fiber cross sections, two adhesive layers (RFL), and the rubber (R) are shown by TEM.

The removal of direct carbon replicas is dependent upon the polymer. Boiling xylene vapor was used to remove drawn PE from replicas [436] in work on drawn polymer morphology. A direct carbon replica method for a PBT impact fracture surface was described by evaporation of platinum at 20° and PBT removal in hexafluoroisopropanol (HFIP) [437], Latex film coalescence in poly(vinyl acrylate) homopolymer and vinyl acrylic copolymer latexes was studied using direct replicas [438]. As the latex films have a low glass transition temperature, they were cooled by liquid nitrogen to about -150°C in the vacuum evaporator and shadowed with Pt/Pd at 45° followed by deposition of a carbon support film at 90° to the specimen surface. The latex films were dissolved in methyl acetate/methanol. Transmission electron microscopy micrographs of the latex films show the difference between films aged for various times (see Section 5.5.2). 

Figure 4.28. Transmission electron microscopy micrographs of replicas from a polycarbonate disk, made by shadowing from opposite directions normal to the grooves to illustrate the asymmetry of the grooves. In the top photo, the shadowing direction is radially inward, whereas for the bottom photo the shadowing direction is radially outward [443]. The inner edge (arrowhead in top photo) was found to have a much steeper slope than the outer edge (arrowhead in bottom photo). (From Baro et al. [443] used with permission.)...

Figure 4.29. Transmission electron microscopy micrograph of a two stage replica made of the surface of an experimental stretched polypropylene film. The replica was shadowed with chromium at an angle of 30°. Slit-like voids are seen that are formed in rows or channels separated by oriented fibrils.

Figure 4.48. Transmission electron microscopy micrographs of freeze dried polystyrene latex (A) used as a control for the experiment shows three dimensional particles with no deformation, whereas an air dried film forming latex (B) shows flat regions that have no shadow. The same latex as in (B) after freeze drying is clearly three dimensional, based on the shadows present (C).

Figure 5.12. A microporous fiber is shown in the SEM and TEM micrographs. The fiber is seen to have voids in the fracture views (A and B), but the voids are not clearly defined. The outer fiber surface (C) also has voids, and particles are observed within some of them. Transmission electron microscopy micrographs of the fiber cross sections (D and E) reveal voids (white regions) that are smaller in size in an outer micrometer sized band than those in the central portion of the fiber.

Figure 5.14. Transmission electron microscopy micrographs of p)olyester fiber cross sections reveal the size of the pigment particles. The optical inset (A) shows fibers with dense particles in greater amounts than seen by TEM due to the difference in section thickness. The dense particle aggregates are titanium dioxide particles. The fiber exhibits no major structural detail. The dense lines are knife marks produced during...

Figure 5.70. A phase contrast optical micrograph (A) of an impact modified nylon shows the fine dispersion of modifier in the matrix. Transmission electron microscopy micrographs of a cryosection, stained with ruthenium tetroxide (B and C), show more detail and finely dispersed subinclusions (arrows) within the elastomeric phase. Scanning transmission electron microscopy (D) of an unstained cryosection shows less dense regions in a darker background due to mass loss of the rubber phase during exposure to the electron beam, resulting in contrast enhancement.

Figure 5.71. Transmission electron microscopy micrographs of ternary blends (A) PA 6/EPR-g-MA/IA and (B) PA 6/SEBS-g-MA/IA. Scale bars are l rni. (From Radovanovic et al. [357], (2004) Elsevier used with permission.)...

Figure 5.109. Transmission electron microscopy micrographs of cryomicrotomed sections of a nylon/clay nanocomposite produced by continuous chaotic blending forms layers of oriented platelets and matrix polymer. (From Zumbrunnen et al. [502, 503] used with permission of the Society of Plastics...

Figure 5.114. Transmission electron microscopy micrographs of several emulsion particle samples show a range of aggregation. An air dried droplet (A) resulted in agglomerated flat particles. More three dimensional particles would still be difficult to measure as they are touching (B). The emulsion particles (C) are well dispersed, and shadowing with chromium clearly shows that they are discrete spheres after freeze drying.

Transmission electron microscopy micrographs are shown as an example of both the replication method and the effect of aging on... 

Figure 5.115. Vinyl acetate latex film coalescence is shown by TEM of platinum-palladium-carbon replicas from aged latex films cast on glass. Transmission electron microscopy micrographs show the particulate nature of a film aged for 8h (A and B) compared with the flat film observed after 15 days aging (C).

Figure 5.144. Transmission electron microscopy micrographs of ultrathin longitudinal sections of an aromatic polyamide fiber show the banded structures in bright field (A) and the crystallites in dark field (B).

Thermotropic aromatic copolyesters have a major advantage over the lyotropes, as the former can be melt processed. Temperature affects the orientation and the mechanical properties, and the copolyesters have been shown to be biphasic by SEM [694-696], optical, and TEM [697-699] techniques. The biphasic structure of X7G has been reported [699] for extruded fibers by optical and EM imaging and microdiffraction. Transmission electron microscopy micrographs of ultrathin longitudinal sections reveal a dense dispersed phase elongated along the fiber axis (Fig. 5.147). Microdiffraction from regions 20-100 nm across show the... 

Figure 5.152. Transmission electron microscopy micrographs of sonicated fibrils, shadowed with metal in order to provide information about the three dimensional structure of (A) Vectran and (B) Kevlar fibers, illustrate the tape-like structure. A range of fibrils are observed that are long and are seen to fibrillate into finer fibrils. Twisting and a cotton-like flat, twisted, or tape-like fibril structure is observed. The aramid fiber (B) is shown to fibrillate into units less than 10 nm wide. (From Sawyer et al. [632] used with permission.)...

Figure 3.3 Typical transmission electron microscopy micrographs (a) 0.5 wt% PtBMA-b-Cso in 0.75 ethyi acetate molar composition (b) 1.0wt% PtBMA-b-Cso in 0.92 ethyl acetate molar composition (c) close up view of a single aggregate of 0.5 wt% PtBMA-fa-Cso In 0.75 ethyl acetate molar...

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