Nanofillers organization structures

Nanofillers have a multiscale organization. The upper level of said organization refers to their distribution and dispersion in the rubber matrix. The lowest level of nanofiller organization refers to the structure of individual particles and of aggregates. In this section, the lowest level of nanofiller organization is discussed, presenting structural features of C, OC, CNT, GE and GNP, in their pristine state. 

On these bases, it is clear that the achievement of the improvements above reported is first based on the ultimate distribution and dispersion of nanofillers. However, also the control of nanofiller particles organization, in aggregates and agglomerates, plays a key role. To pursue advanced properties moving from the nanocomposite structure, the multiscale organization of nanofillers in the polymer matrix has to be assessed. 

The use of organic nanofillers allows the reduction of the filler content required to achieve high thermal conductivity. In particular, multi-walled carbon nanotubes (MWCNTs), with their one-dimensional structure, high aspect ratio and superior thermal conductivity (3000 W/mK for an individual MWCNT and 200 W/mK for bulk MWCNTs at room temperature (Yang et al., 1991)) have recently attracted great attention in the scientific world. The influence of different carbon nanotube types, particle content, interfacial area, surface functionalization and aspect ratio on the electrical and thermal conductivity of epoxy resins has been investigated (Gojny et al., 2006). 

Recentiy, a new class of organic-inorganic hybrid materials based on the ultra incorporation of nano-sized fillers (nanofillers) into a polymer matrix has been investigated. Nanotechnology is the aptitude to work on a scale of about 1-100 nm in order to understand, create, characterize and use material structure, devices, and system with unique properties derived from their base on the nanostructures. Nanocomposites could exhibit exclusive modifications in their properties, compared with conventional composites in terms of physical properties, including gas barrier, flammability resistance, thermal and environmental stability, solvent uptake, and rate of biodegradability of biodegradable (Chivrac et al. 2009). 

From the scientific viewpoint, a number of issues are yet to be solved for improving the quality of the material as well as the fabrication process. An important factor to warrant the properties of composites is the quality of the fillers. They should have a well-defined distribution and will therefore need a precise control over the fabrication process. The dispersion of fillers in the polymer matrix should also be carefully performed and controlled for obtaining reliable expected properties. Future developments of nanotechnology should take into account this aspect to simplify the fabrication process by keeping the same material quality. The concept of nanocomposites may be oriented toward a better organization of the structure with ordered or aligned nanofillers, to allow production of high-quality materials at low cost. 

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