Organoclay structure

Pluta, M. Melt compounding of polylactide/organoclay Structure and properties of nanocomposites. J. Polym. Sci., Part B Polym. Phys. 44, 3392-3405 (2006)... 

P. J. Yoon, D. L. Hunter, and D. R. Paul, Polycarbonate nanocomposites. Part 1. Effect of organoclay structure on morphology and properties. Polymer, 44 (2003), 5323-39. 

In this case we believe that during the melting process, a minimum part of the organoclay structure collapsed and deintercalated part of the organic modifier DEDMEL. It is reasonable to emphasize that the peak at 1.60 nm shows an intensity much lower than that of the pristine organoclay. We are aware that more information is necessary but some authors, in analogous cases, explain the possible intercalated nanocomposite formation with XRD data alone [60, 67, 76-79]. 

The authors [2] considered some aspects of nanofiller (organoclay) structure influence on nanocomposites flame-resistance. Firstly, the nanocomposite with exfoliated organoclay possesses higher flame-resistance, than... 

FIGURE 7.3 Organoclay structures (a) monolayer, (b), bilayer, (c) pseudotrimolecular layer, and (d) and (e) paraffin-type arrangement of the organic molecules within the clay mineral layers. (From Bergaya F. and Lagaly G., 2001, Applied Clay Science 19, 1-3.)... 

Polycarbonate nanocomposites were prepared by melt compounding and the effect of organoclay structure on color formation was examined. Darker colored nanocomposites were obtained for samples containing the organoclay with double bonds in the hydrocarbon tail, compared to those with saturated organic modifiers. The presence of both hydroxy-ethyl groups and tallow tails led to the most important color changes [19]. 

Organoclay materials with higher-order organization can also be prepared by template-directed methods involving self-assembled supramolecular structures. In this approach, preformed organic architectures in the form of tubes, fibers, hollow shells, gyroids, helicoids, and so on are transferred into hybrid materials exhibiting structural hierarchy, complex form and ordered mesoporosity [47-55]. For example,... 

The structural and functional integrity of organoclay-wrapped Mb and Hb molecules was demonstrated by retention of the secondary protein structure as well as distinctive shifts in the absorption spectra associated with oxygen or carbon monoxide binding to the heme metallocenter. The latter indicated that the wrapped... 

Das et al. [89] observed that both sulfur and peroxide vulcanizations of NBR filled with organoclay lead to intercalated-exfoliated structures of the layered silicate. They also reported that the use of excess stearic acid could lead to exfoliation of the clay layers in NBR when cured with sulfur. 

It is observed from this figure that there are a lot of small dark lines preferably oriented in a north-south direction. Here, the organoclay is distributed evenly in the whole rubber matrix. Some small dark clusters are shown enlarged in Fig. 29b. These structures are formed due to the separation of the polar XNBR phase from the nonpolar S-SBR matrix. Furthermore, exfoliated layers of organoclay are visible in the interface between the two polymer phases, which obviously promotes a better compatibility between XNBR and S-SBR phases. Figure 29c displays the ... 

A good state of dispersion of the organoclay has been found in the CR matrix. The exfoliated structure can be directly observed from the of the OMMT-filled CR composite (left-hand image in Fig. 30). It is noticed from this micrograph that all silicate layers are exfoliated and distributed very nicely throughout the whole rubber matrix. It is also observed that some of the exfoliated clay platelets form a house of cards structure (right-hand image in Fig. 30). 

In order to prove the importance of the delaminated layer structure in the direct (melt) intercalation, the intercalation of stearic acid molecules into the clay galleries has been studied by premixing them with organoclay and then successfully incorporating this modified clay into the rubber matrix [59]. A schematic presentation of such modification of clay is given in Fig. 37. 

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