Scanning electron microscopy curing

The shape of the dispersed phase droplets was investigated experimentally by Lissant and coworker by scanning electron microscopy (SEM) on cured HIPEs of water in a styrene-based resin [5], At high internal phase volumes, droplets were indeed polyhedral, and appeared to be relatively monodisperse in size. 

Fig. 2 Scanning electron microscopy images (A) pure LDPE (B) silane grafted and cured in hot water and (C) electron beam irradiated.

Figure 9.12 Fast-freeze cryogenic scanning electron microscopy for visualizing structure development In drying or curing coatings...

Scanning electron microscopy (SEM) Pig. 10, revealed an increase in the surface concentration of copper domains following additional cure. An increase in the thickness of the copper oxide layer from approximately 700 A to 1300 k was also noted by transmission electron microscopy. Post-processing was considered by the authors to be analogous to sintering wherein, small particles fuse to become a large solid mass. 

Not only new techniques deserve attention, but also any new developments in old techniques, such as scanning electron microscopy (28). Scanning electron microscopy, for example, can now enhance the examination of the adhesive interface in greater detail. Two other old techniques have also found new applications in adhesive chemistry. One is dynamic mechanical analysis (29,30), which has been accepted for the study of pressure-sensitive adhesives and the curing mechanism of epoxy resins (31,32). The other is the use of a fluorescence probe to examine the curing mechanism (33). 

In this framework, in the specially designed mortars consisting of binders of either lime and metakaolin or natural hydraulic lime and fine aggregates of carbonate nature, nano-titania of anatase (90 per cent) and rutile (10 per cent) form has been added (4.5-6% w/w of binder). The aim was to study the effect of nano-titania in the hydration and carbonation of the above binders and to compare the physico-chemical properties of the nano-titania mortars with those mortars without nano-titania, used as reference. Thermal analysis (DTA-TG), infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed to investigate the evolution of carbonation, hydration and hydraulic compound formation during a six-month curing period. Furthermore, the stone-mortar interfaces, the adhesion resistance to external mechanical stress, relative to the physicochemical characteristics of the stone-mortar system and the role of the nano-titania as additive, were reported and are discussed in this chapter. 

Surface analysis such as dynamic contact angle and surface tension are used to ensure proper wetting of epoxy and the substrate. Microscopic techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), are widely used to study morphology, fracture, and adhesion issues of cured epoxy systems. Chemical analysis techniques, such as micro-IR, X-ray photoelectron spectrometry (XPS), and secondary ion mass... 

The mechanical properties were measured in accordance with ISO 37. The tensile tests were carried out using a Zwick 1435 Universal Testing Maschine with the cross-head 500 mm/min. The samples had the standard dumbbell shape. The micro structure of the vulcanizates surface was observed by scanning electron microscopy (SEM) LEO 1530 Zeiss. The samples of cured sheets were fixed on the sample holder, then gold-coated and secondary electron images were recorded. 

Vulcanization kinetic was studied. Mechanical properties of cured composites before and after various regimes of ceramization were investigated. Ceramic phase obtained after heat treatment was characterized by porosimetry and scanning electron microscopy. Morphology and mechanical properties of composites before and after ceramization depend on the type of mineral filler applied, whereas the kinetic of vulcanization is different only for composite containing surface modified montmorillonite. 

No two surfaces are absolutely identical and there will be some contact electrification. The electrostatic theory considers the two surfaces to be bonded as the two plates of an electrostatic condenser, and is due to Deryaguin [30]. According to this theory adhesion occurs due to the electrostatic forces formed by interaction between the substrates. This theory explains the pressure dependence of tack/autohesion very well but it does not explain why raw and compounded rubbers lose most tack/autohesion as they are cured and brought into molecular contact under pressure. Further this theory is also not successful in explaining the time and temperature dependence of the tack/autohesion. By using potential contrast scanning electron microscopy the existence of an electric double layer at the polymer interface has been demonstrated [31]. 

The paper presented by J. P. Wightman e aT, examines metal surface before and after bonding with polyimide resins. Again, as in the previous paper, the critical nature of the boundary layer between the adhesive and the metal surface becomes evident. By use of scanning electron microscopy, electron spectroscopy for chemical analyses, and reflectance infrared spectroscopy, the actual surface and boundary layers are examined. This paper develops experimental and theoretical criteria for evaluating new cured adhesives. 

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