Nanocomposites fluorohectorite

Figure 16.24 shows the schematic representation of dispersed clay particles in a polymer matrix. Conventionally dispersed clay has aggregated layers in face-to-face form. Intercalated clay composites have one or more layers of polymer inserted into the clay host gallery. Exfoliated polymer/clay nanocomposites have low clay content (lower than intercalated clay composites which have clay content -50%). It was found that 1 wt% exfoliated clay such as hectorite, montmorillonite, or fluorohectorite increases the tensile modulus of epoxy resin by 50-65%. ... 

FIGURE 12.7 Temperature dependence of o-Ps (a) lifetime and (b) intensity for organically modified fluorohectorite (o), polystyrene ( ), and 25 wt%/75 wt% polystyrene/organicaUy modified fluorohectorite nanocomposite ( ). The solid line in (a) indicates the weight-average sum of the o-Ps lifetime values of the fluorohectorite and the polystyrene. (Adapted from Olson et al. [1997].)... 

Since the initial absorption (i.e. color) of the nanocomposite increases with montmorillonite addition, future investigations should focus on examining synthetic aluminosilicates that do not contain isomorphic substitution from transition metals such as Fe. Alternative types of inorganic fillers include laponite, fluorohectorite or synthetic silicic acids (31). Note that the UV exposure is not only an on-orbit concern, but will drastically affect life-cycle and long-term environment stability and performance of nanocomposites used in external terrestrial environments. 

Ganter et al. [62], utUized a synthetic layered fluorohec-torite silicate and organomontmorillonite to evaluate the role of functional rubber exchanged onto the synthetic clay in the preparation of styrene-butadiene rubber nanocomposites. The functional rubber that was exchanged onto the fluorohectorite was amino-terminated polybutadiene. The styrene-butadiene was dispersed in solvent and then dis-... 

In some types of nanocomposites the nature and aspect ratios of the assembled silicate structures may affect their ability to resume a reasonably coherent structure during char formation. Such structures would be less effective in reducing movement of volatiles and new fuel and so have a reduced flame retardaney eapability. This latter phenomenon was found in some polystyrene nanocomposites that utilised fluorohectorite. PS composites using MMT did show a decrease in flammability. 

Fig. 11. Powder XRD patterns of s-caprolactone-fluorohectorite nanocomposite before (solid line) and after (dashed line) polymerization. Insets are schematic illustrations (not drawn to scale) corresponding to the intercalated monomer (left) and intercalated macromolecule (right). Reprinted with permission from Ref. 84. Copyright (1993) American Chemical Society.

M. Zanetti, G. Camino, and R. Mulhaupt, Combustion behaviour of EVA/ fluorohectorite nanocomposites. Polymer Degradation and Stability, 74 (2001), 413-... 

Fig. 10 Route for the preparation of PE/organically modified fluorohectorite nanocomposite using Brookhart s single-component palladium complex. Reproduced with kind permission from Bergman et al. [101]...

Zanetti, M. Camino, G. Miilhaupt, R. Combustion behaviour of EVA/fluorohectorite nanocomposites. Polym. Degrad. Stab. 2001, 74, 413-417. 

Figure 9.7 adapted from Macromolecular Rapid Communications, Vol. 27,2006, Authors Siengchin S and Karger-Kocsis J, Title Creep behavior of polystyrene/fluorohectorite micro- and nanocomposites, pp. 2090-2094, Copyright (2008) with permission from Wiley-VCH Verlag GmbH Co. 

The next example is a nanocomposite of NBR with a fluorohectorite. In this composite the transmission electron microscopy (TEM) and... 

Figure 3. TEM photographs of a non-layered clay (a) and sodium fluorohectorite-filled NR-based nanocomposite (b) produced by latex compounding. Silicate content of 10 phr.

Figure 4. XRD spectra of layered silicate (sodium fluorohectorite) reinforced nanocomposites of various compositions.

Table 1. Mechanical properties of the rubber nanocomposites before and after aging. LS (sodium fluorohectorite) content 10 parts per hundred rubber (phr) in all samples.

Figure 2. XRD spectra of the pristine layered silicate (LS Na-fluorohectorite) and cast TPU nanocomposite containing 10 parts per hundred resin (phr) LS...

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