Morphological characteristics and mechanical properties of PP‐EP/EVA blends were studied and compared to those of PP/EVA previously reported. For the PPEP/EVA blends, interfacial interactions in amorphous zones, which were associated with shifts in Tg, were well defined compared to those of PP/EVA blends, although the nature of crystalline zones was similar for both systems. At EVA concentrations up to 20%, the elongation at break and impact strength slightly increased in both systems. However, PP‐EP/EVA displayed higher values of these properties compared with PP/EVA. At high EVA concentrations (above 20%), the indicated properties were enhanced in both polymeric systems, and the same proportional behavior was maintained. The decrease in tensile strength of PP‐EP/EVA was not as marked as in PP/EVA with the addition of EVA, and it remained below PP/EVA at high EVA concentrations. The improvement in properties of PP‐EP/EVA was attributed to favorable interactions between the ethylene groups contained in both copolymers. These interactions rendered a high degree of compatibility between the PP‐EP and EVA components.
Surface modification of copper nanoparticles (CuNPs) was performed in a radiofrequency plasma reactor using acrylic acid, acrylonitrile, and methyl methacrylate monomers. Treated and untreated CuNPs were analyzed by thermogravimetrical analysis, X-ray diffraction (XRD), transmission electronic microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. The oxidation of CuNPs was assessed by XRD as a function of the plasma treatment. The antibacterial properties of plasma treated CuNPs were evaluated using Pseudomonas aeruginosa and Staphylococcus aureus. It was found that the plasma modification did not affect significantly the antibacterial properties of CuNPs, since the plasma films deposited on their surfaces were in the order of few nanometers and copper ions traveled easily through the plasma polymer to interact with the bacteria. Further, the nanocoating deposited by plasma on the CuNPs protects them against the oxidation even in solution dispersions. CuNPs coated with acrylonitrile presented a slightly lower antibacterial activity than pristine CuNPs.
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