A layer of a polyethylene-silver nanoparticles composite was deposited on a five layer barrier film structure. Different methods were used for the nanocomposite layer deposition: laminating, casting, and spraying over the multilayer structure. For the casting and spraying methods, the silver nanoparticles were previously dispersed in the polymer solution, with the assistance of ultrasound energy. The effect of silver nanoparticles and deposition method on the barrier, mechanical, and optical properties of the multilayer films was evaluated. The efficiency of silver ion release from the PE-Silver nanocomposite deposited on the multilayer films and their antimicrobial characteristics were investigated and discussed. The silver ion release and biocide effect of the multilayer films was found to be dependant on the silver nanoparticle content and on the deposition method used. The observed results could be helpful in the design of industrial films for packaging.

Summary: The effect of peroxide functionalization of carbon nanofibers (CNF) on the physical and mechanical properties of polystyrene (PS)–CNF nanocomposites prepared via melt mixing was studied. The CNF functionalization was evidenced by Raman spectroscopy, comparing the ratio of peaks at 1 371 and at 1 590 cm−1 (peaks related to the disordered sp3‐hybridized carbon atom and to the graphitic structure of the sp2‐hybridized carbon atoms, respectively). The variation of the storage (E′) and tensile modulus (E) of the PS–CNF composites as a function of the untreated and peroxide treated CNF concentration were evaluated. Three different peroxide concentrations were used for treating the CNF. It was found that both E′ and E increase with CNF concentration and, in addition, increase further with the peroxide treated CNFs. Nonetheless, it was found that the greater the peroxide concentration used in treating the CNF, the greater the PS degradation via free radical attack on the polymer chain, with the corresponding negative effect on the storage and tensile modulus. Dispersion of the CNF was assessed using scanning and optical microscopy, and the positive effect of the peroxide treatment on the dispersion of the CNF is evidenced.Tensile stress‐strain behavior of PS/CNF nanocomposites.magnified imageTensile stress‐strain behavior of PS/CNF nanocomposites.

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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.

The effect of graphene oxide (GO) functionalized with 3‐amino‐propyl‐triethoxy‐silane(APTS), organo‐vermiculite(OVMT), and magnesium hydroxide (MH) combinations on mechanical, thermal, and flame retardant (FR) properties of polypropylene (PP) was studied. GO was obtained via a slight modification of the Hummers method and then chemically surface functionalized with APTS. VMT clay was modified with maleic anhydride (MA) via a chemical reaction with acetic acid to increase its inter‐laminar spacing. The results of Fourier‐transform infrared analysis, X‐ray diffraction, and transmission electron microscopy demonstrated that APTS had been successfully attached to the GO and that VMT was modified with MA. Subsequently, each functionalized filler was incorporated in combination with MH to the flame‐retardant‐polypropylene system. The performance of PP composites with each filler as well as with their combinations, including a reduced “30 wt% of MH” were compared with the reference PP composite with 55 wt% of MH as the only FR additive. PP grafted with MA (PP‐gMA) and PP grafted with amine‐alcohol(PP‐gDMAE) were used as compatibilizer agents between each filler and the polymer matrix. The results obtained confirmed a better mechanical and FR performance when using PP‐gDMAE. Composites with 30 wt% MH combined with very low contents of GO (0.5 and 1.0 wt%) showed improved FR properties, similar to the reference sample, with an evident reduction in peak of the heat release rate (pHRR) and total heat release and increased limiting oxygen index (LOI) values. The combination of MH and GO showed the best FR and mechanical properties: LOI of 22.5% and pHRR of 540 kW/m2 which were very similar to the reference sample. In addition, PP‐gDMAE improved the OVMT exfoliation with a slight increase in the intergallery spacing but OVMT and modified GO combinations did not significantly improve the FR and mechanical properties compared with the effect of MH and modified GO combinations. The combination of MH and modified GO makes it possible to reduce the total MH filler content from 55 to 30 wt% to accomplish the FR requirements and with enhanced mechanical properties. This filler combination promoted the formation of a continuous, intact residual char layer on the PP surface, which acts as an insulating barrier to protect the base material. These filler combinations offer an option to meet the FR properties using halogen‐free FR with better mechanical properties.