Effects of Nanofillers on Material Properties

FIGURE 2.3 Relevant parameters needed to describe the morphology of a polymer/ layered-silicate nanocomposite. Layer parameters layer thickness (H), lateral contour size 2R ), and corresponding projected lateral size (2R). Layer stack parameters distribution of layer-layer distances within a stack (dooL di, d2, d ), distortion in d (Ad), and mean number of layers per stack (N). Distribution of stacks parameters mean particle-particle distance between center of mass of stacks (/), relative particle-particle orientation [(t (ni,nic)], and fraction of layer stacks consisting only of individual layCTs (x)-(Adapted from Ref. 68.) 

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Interfacial structure is known to be different from bulk structure, and in polymers filled with nanofillers possessing extremely high specific surface areas, most of the polymers is present near the interface, in spite of the small weight fraction of filler. This is one of the reasons why the nature of the reinforcement is different in nanocomposites and is manifested even at very low filler loadings (<10 wt%). Crucial parameters in determining the effect of fillers on the properties of composites are filler size, shape, aspect ratio, and filler-matrix interactions [2-5]. In the case of nanocomposites, the properties of the material are more tied to the interface. Thus, the control and manipulation of microstructural evolution is essential for the growth of a strong polymer-filler interface in such nanocomposites. 

Nanodiamond powder technology began to be rapidly developed in the mid-1980s. UDD is close to this class of materials by its characteristics. A large body of information on the positive effect of nanofillers on the mechanical properties of various composite materials, polymer composites included, appeared in the patent and technical literature. Still, in spite of UDD evidently being technically... 

In this chapter, the study carried out on nanofillers reinforced natural/synthetic rubber has been discussed. After a description on the NR rubber and CaCOs as filler, the development of synthetic composites with the incorporation of micro and nano-CaC03 as a filler material has also been discussed for comparative study. In particular, the role of fillers on the property modification of rubber properties, such as surface properties, mechanical strength, thermal conductivity, and permittivity has been mentioned. The effectiveness of this coating was demonstrated. The importance of well-dispersed nanoparticles on the improvement of the mechanical and electrical properties of polymers is also emphasized. However, one of the problems encountered is that the nanoparticles agglomerate easily because of their high surface energy. 

Graphene-polymer nanocomposites share with other nanocomposites the characteristic of remarkable improvements in properties and percolation thresholds at very low filler contents. Although the majority of research has focused on polymer nanocomposites based on layered materials of natural origin, such as an MMT type of layered silicate compounds or synthetic clay (layered double hydroxide), the electrical and thermal conductivity of clay minerals are quite poor [177]. To overcome these shortcomings, carbon-based nanofillers, such as CB, carbon nanotubes, carbon nanofibers, and graphite have been introduced to the preparation of polymer nanocomposites. Among these, carbon nanotubes have proven to be very effective as conductive fillers. An important drawback of them as nanofillers is their high production costs, which... 

As it is known [13, 14], the scale effects are often found at the study of different materials mechanical properties. The dependence of failure stress on grain size for metals (Holl-Petsch formula) [15] or of effective filling degree on filler particles size in case of polymer composites [16] are examples of such effect. The strong dependence of elasticity modulus on nanofiller particles diameter is observed for particulate-filled elastomeric nanocomposites [5], Therefore, it is necessary to elucidate the physical grounds of nano- and micromechanical behavior scale effect for polymer nanocomposites. 

This book focuses on the synthesis and characterization of natural rubber composites and nanocomposites, the interaction between reinforcing agents and the rubber matrix and their effect on different properties. The reinforcing effect of traditional fillers in micro range and the effectiveness of these nanofillers are discussed. This book on natural rubber and nano composites comprises of the most recent research activities that will, unquestionably, be a vital reference book for scientists in both the academic and industrial sectors, as well as for individuals who are interested in natural rubber materials. 

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