Nanocomposite ordered intercalated

Nevertheless, XRD is a useful tool to study the d-spacing of ordered intercalated polymer nanocomposites, it might not be sufficient for exfoliated nanocomposites with no peak. It is generally accepted that transmission electron microscopy (TEM) is the best direct method to demonstrate the dispersion of nanofillers in a polymer matrix. It has been widely used to investigate the dispersion of day in a PET matrix. Eigure 5.4 shows the TEM study of PET/MMT composites [14]. It can be observed that the dispersion of clay in the composites varies due to different processing procedures. It can be either labeled as nanocomposites or conventional... 

The reduction in the PHRR observed by Camino et al. in a similar DGEBA-anhydride system is considerably higher. They used methyl tetrahydrophthalic anhydride as the curing agent and 10 wt% organoclays. The resulting nanocomposites had an ordered intercalated-exfoliated structure. A reduction of 68 and 38% in the PHRR compared to neat epoxy was observed in a nanocomposite... 

In order to understand the thermodynamic issues associated with the nanocomposite formation, Vaia et al. have applied the mean-field statistical lattice model and found that conclusions based on the mean field theory agreed nicely with the experimental results [12,13]. The entropy loss associated with confinement of a polymer melt is not prohibited to nanocomposite formation because an entropy gain associated with the layer separation balances the entropy loss of polymer intercalation, resulting in a net entropy change near to zero. Thus, from the theoretical model, the outcome of nanocomposite formation via polymer melt intercalation depends on energetic factors, which may be determined from the surface energies of the polymer and OMLF. 

Dispersion The degree of dispersion of the nanoplatelets is determined by the degree of delamination of the clay. The fully delaminated (exfoliated) nanocomposite presents much higher values for the tortuosity factor and the aspect ratio in comparison with the partially delaminated (intercalated) nanocomposite. This means that the clay particles that grow as aggregates or books of sheets must be broken up or exfoliated into individual sheets that have a thickness of the order of 1 nm, with lengths and widths of the order of 500 nm. 

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