Copper nanoparticles were synthesized by thermal decomposition using copper chloride, sodium oleate, and phenyl ether as solvent agents. The formation of nanoparticles was evidenced by the X-ray diffraction and transmission electron microscopy. The peaks in the XRD pattern correspond to the standard values of the face centered cubic (fcc) structure of metallic copper and no peaks of other impurity crystalline phases were detected. TEM analysis showed spherical nanoparticles with sizes in the range of 4 to 18 nm. The antibacterial properties of copper nanoparticles were evaluated in vitro against strains of Staphylococcus aureus and Pseudomonas aeruginosa. The antibacterial activity of copper nanoparticles synthesized by thermal decomposition showed significant inhibitory effect against these highly multidrug-resistant bacterial strains.

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In the present work, the effect of distribution of Carbon Black (CB) and rubber viscosity over the conductivity of rubber blend composites was studied. Preferential location of CB predicted by surface tension measurements and calculation of interfacial energy (wetting coefficient) was corroborated by dynamic analysis (DMA) as well as bound rubber experiments. In this respect, the employment of the DMA technique to infer preferential distribution of CB, through the following of changes in the loss tangent (Tan δ), were proposed and successfully assessed in this study. A double percolation effect was evidenced by the appearance of a maximum in conductivity at relatively low EPDM content and CB concentration; however, when blend viscosity increases due to the addition of EPDM (the most viscous rubber), the double percolation effect is suppressed and the conductivity falls due to the prevailing dispersion effect of CB particles. According to these results, the blend viscosity was found to play a major role in the final conductivity of the studied composites.

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