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International audience; In this work, two copper metal matrix composites (MMCs) reinforced with 20 wt.% of Ti(C,N) or Ti2AlN particles were studied. The reinforcement particles were synthesized by flash sintering under 2 bar nitrogen atmosphere causing an SHS reaction ignited by electrical current. This reaction led to produce TiC0.7N0.3 solid solution for the MMC1 reinforcement and Ti2AlN, TiN, and Ti3Al titanium aluminide for the MMC2 reinforcement. Both MMCs were densified by liquid phase sintering. The structural characterization was performed by XRD analysis while the morphology and chemical element distribution of both MMCs were analyzed by SEM and EDS. The structure of the two MMCs was relatively dense and showed good wettability. The mechanical and tribological behavior of MMCs evaluated by nanoindentation and wear testing reveals that the addition of 20 wt.% of reinforcement considerably improves the properties of copper matrix. Indeed, the MMC1 proved to be 3 times harder and 10 times more wear-resistant than the MMC2 composite.

This study focused on the possibility of recycling Waste Tire Rubber (WTR) to be used as polymer modifier. Thus, WTR was grinded into powder, at ambient temperature, with a disc mill PQ500 and microwave electromagnetic energy was used to devulcanize this powder with the final aim of producing a new composite by its incorporation in a thermoset resin. The influence of the treatment microwave energy on the devulcanization ratio was investigated. FTIR analysis revealed that rupture of Sulfur-Sulfur (SAS) and Carbon-Sulfur (CAS) bonds have occurred during the treatment. Swelling analysis showed that the microwave treatment can lead to a very significant degree of devulcanization. The Ground Tire Rubber (GTR) and the Devulcanized Ground Tire Rubber (DGTR) were then separately used to prepare epoxy based composites. It appeared that epoxy composites filled with DGTR have better mechanical properties than those filled with untreated GTR. This result agrees with scanning electron microscopy observations which highlighted a better interface coherence between DGTR and epoxy. A complementary analysis pointed out a linear relationship between the rubber modulus and the number of crosslink per chain. Fil: Aoudia, Karima. Universite Mouloud Mammeri de Tizi-ouzou; Argelia Fil: Azem, Saïd. Universite Mouloud Mammeri de Tizi-ouzou; Argelia Fil: Aït Hocine, Nourredine. Institut National des Sciences Appliquées; Francia Fil: Gratton, Michel. Institut National des Sciences Appliquées ; Francia Fil: Pettarin, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentina Fil: Seghar, Saïd. Phenix Technolgies; Francia

International audience; In this study, styrene butadiene rubber (SBR) was devulcanized using microwave irradiation. In particular, effectof ionic liquid (IL), pyrrolidinium hydrogen sulfate [Pyrr][HSO4], on the devulcanization performance was studied. It wasobserved that the evolution of the temperature reached by rubber powder exposed to microwave irradiation for differentenergy values was favored by the presence of ionic liquid [Pyrr][HSO4] significantly over the whole range of themicrowave energy values. Beyond the threshold point of 220 Wh/kg, the soluble fraction after devulcanization sharplyincreased with increasing devulcanization microwave energy. For the powder mixed with [Pyrr][HSO4], the increase wasmore significant. Furthermore, the crosslink density was observed to decrease slowly with the microwave energy up to220 Wh/kg, beyond which the crosslink density decreased significantly for the rubber impregnated with IL. For the rubberwith IL, significant and continuous increase in Tg with microwave energy values was observed in comparison with the SBRwhere no change in transition temperature was observed. Mechanical shearing of rubber gums in the two-roll mill favoredthe devulcanization process, which indicated that the combination of mechanical loading with microwave energy and IL isan efficient procedure allowing an optimal devulcanization of rubbers.