Felipe Silva Bellucci

In recent decades, an increasing effort has been made not only to foster cost-effective, competitive and innovative industries but also to create smart materials. In this work, we present the morphological, magnetic and mechanical characterizations, as well as the effect of a magnetic field on the mechanical properties of magnetic nanocomposites type magnetorheological elastomers (MRE), based on carbonyl iron particles, embedded in a silicone elastomer (SR/IRON). These MREs were prepared by the curing process at room temperature of the silicone rubber and different concentrations of iron particles, 18%, 33% and 48% in volume. From mechanical tests assisted by a magnetic field: (i) a strong dependence on the mechanical response with the application of a magnetic field on the samples and (ii) a variation between 34% and 61% on the mechanical properties of the MRE related to the particle concentration in the samples. These results point to the possibility of using these nanocomposites based on silicon rubber and iron as smart materials type MRE and in vibration absorption systems, once they exhibit acceptable values of mechanical dependence with the applied external magnetic field.

In this study the composites which are commonly called NR/CB/Leather were developed in order to apply them as antistatic flooring and coating. They were developed using vulcanized natural rubber, carbon black to add an electric conduction property and industrial leather waste. The leather industrial waste was micronized and added to the rubber matrix in proportions of 60 and 80 phr using an opened mixing cylinder according to ASTM D 3182 standard. The composites were exposed to the sanitizing agents, (i) bleach and (ii) disinfectant, aiming to simulate a real cleaning context, and to meet the health standards of the Brazilian Ministry of health. Physical‐chemical and microbiological evaluations were carried out to determine the structural and chemical stabilities of the composites. After this, low water absorption level (2016, 133, 43618.

Nanocomposites are multiphase materials of which, at least one of the phases, has a dimension smaller than 100 nm. These materials have attracted technological and scientific interest due to their multifunctional characteristics and potential, which allow them to combine unique properties which are not found in traditional commercial materials, such as natural rubber alone. The objective of this work is to analyse the toxicity of nanoparticles and nanocomposites when applied to mammal cells in order to obtain bioactive agents, as well as to evaluate the potential to be applied in biological systems. Ferroelectric ceramic nanoparticles of KSr2Nb5O15 (KSN) and paramagnetic ceramic nanoparticles Ni0.5Zn0.5Fe2O4 (NZF) were prepared and utilized to produce functional and multifunctional nanocomposites based on vulcanized natural rubber (NR/KSN and NR/NZF) with different nanoparticle concentrations. For both kinds of nanoparticles and both classes of nanocomposites, independently of the nanoparticle concentration, it is not possible to observe any reduction of the cellular viability until the incubation time is finished. In this way, these results point to the possibility of using these nanoparticles and nanocomposites, from the toxicity point of view, as bioactivity agents in biological systems based on mammalian cells.