Nanocomposites of poly(methyl methacrylate)/reduced graphene oxide (PMMA/rGO) without and with decorated magnetite nanoparticles with a segregated structure were prepared using emulsifier-free emulsion polymerization. Various characterization techniques were employed to validate the presence of the nanofillers and the formation of the segregated structure within the nanocomposites. The percolation threshold of the nanocomposites was found to be 0.3 vol %, while a maximum electrical conductivity of 91.2 S·m and electromagnetic interference shielding effectiveness (EMI SE) of 63.2 dB (2.9 mm thickness) were achieved for the PMMA/rGO nanocomposites at a loading of 2.6 vol % rGO. It was also observed that decorating rGO with magnetite nanoparticles (hybrid nanocomposites) led to a tremendous increase in EMI SE. For instance, 1.1 vol % PMMA/rGO nanocomposites indicated an EMI SE of 20.7 dB, while adding 0.5 vol % magnetite nanoparticles enhanced EMI SE to 29.3 dB. The excellent electrical properties obtained for these nanocomposites were ascribed to both superiorities of the segregated conductive structure and magnetic properties of the magnetite nanoparticles.

Silver nanowires (AgNWs) were synthesized by AC electrodeposition of Ag into porous aluminum oxide templates. AgNWs were embedded into polystyrene via a solution processing technique to create a nanocomposite. For comparison, carbon nanotube (CNT)/polystyrene nanocomposites were identically generated. TEM and XRD analyses confirmed the synthesis of AgNWs with an average diameter and length of 25 nm and 3.2 mm, respectively. TEM images also revealed that at the molding temperature (240 C) AgNWs transformed into a chain of nanospheres. At low filler loadings, the AgNW/polystyrene nanocomposites presented inferior electrical properties compared to the CNT/polystyrene nanocomposites. This was attributed to a lower aspect ratio, fragmentation phenomenon and poorer conductive network for AgNWs. However, at high filler loadings, the electrical properties of the AgNW/polystyrene nanocomposites significantly increased. It seems that at high filler loadings, the conductive network was well-established for both types of nanocomposites and thus, the higher innate conductivity of AgNWs played a dominant role in presenting superior electrical properties. Fig. 5 EMI SE (overall, reflection and absorption) of AgNW/PS and MWCNT/PS nanocomposites as a function of nanofiller loading.Fig. 6 (a) Imaginary permittivity, and (b) real permittivity as a function of nanofiller loading. 56596 | RSC Adv., 2015, 5, 56590-56598 This journal is

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Nanocomposites were prepared by adding 1-3 vol % multiwalled carbon nanotubes (MWCNTs) to polyamide 6 (PA6), polypropylene (PP), and their co-continuous blends of 60/40 and 50/50 volume compositions. Because of the good interaction and interfacial adhesion to the PA6, nanotubes were disentangled and distributed evenly through nanocomposites containing PA6. In contrast, lack of active interactions between the matrix and the CNTs resulted in poor tube dispersion in PP. These observations were then verified by studying the rheology and electrical conductivity of their respective nanocomposites. Absence of percolated CNT clusters and possible wrapping of the tubes by PA6 resulted in low electrical conductivity of PA6/CNT nanocomposites. On the other hand, despite the weak dispersion of the tubes, electrical conductiv-ities of PP/CNT nanocomposites were much higher than all other counterparts. This could be the result of good threedimensional distribution of the agglomerated bundles and secondary aggregation of tubes in PP. Adding CNTs to blends of PA6/PP (60/40 and 50/50) resulted in almost full localization of carbon nanotubes in PA6, leading to their higher effective concentration. At the same CNT loadings, the blend nanocomposites had three to seven orders of magnitude higher electrical conductivity than pure PA6.