Abstract This work focuses on characterizing the role of different triblock copolymers on the dispersion of nanoparticles in an epoxy matrix and in the thermal and mechanical properties of the resulting nanocomposites, using Poly (ethylene glycol) - block-poly (propylene glycol) - block-poly (ethylene glycol) (PEG-b-PPG- b-PEG) with 30% PEG, and poly (propylene glycol) - block-poly (ethylene glycol) - block-poly (propylene glycol) (PPG-b-PEG-b-PPG) with 50% PEG. The nanoparticles employed have different geometries: carbon nanotubes, graphene nanoplatelets and carbon black (spherical). Both copolymers were miscible in epoxy. The results suggest that the copolymers viscosity may be interfering with the dispersion of the nanoparticles in the matrix: the PPG-b- PEG-b-PPG50% copolymer has a higher viscosity than the PEG b-PPG-b-PEG30%, which facilitates their dispersion and an increase in mechanical properties. The PEG fraction was an important factor in the dispersion of nanoparticles in the epoxy matrix. The higher the PEG content in the copolymer block, the greater the synergy shown in the mechanical properties, since the nanoparticles inhibited the plasticizing effect of the block copolymer.

ABSTRACT Success in production of any perennial tree depends on the use of high-quality seedlings. This study aimed to evaluate cultivation benches with reflective material and protected environments for production of rubber tree rootstock seedlings. The experiments were conducted in two types of protected environments: 35% shading aluminized screen and 30% shading black screen. Cultivation benches with and without reflective material were tested inside the protected environments. A completely randomized design with 7 replications and 5 seedlings per plot was adopted for each environment, and the environments were compared by joint analysis. Solar radiation (global and photosynthetically active) was the most influencing micrometeorological factor on plant environment and plant growth differentiation. Regardless of the environment, the use of reflective material in cultivation bench had a positive effect on production of rubber rootstock seedling (clone GT1), providing seedlings with a robust root system and better quality. The use of reflective material also improved rubber tree rootstock seedlings (clone GT1) grown in the black screen environment.

ABSTRACT The Achachairu (Garcinia humilis) is a Bolivian exotic fruit that has been produced and commercialized a few years in Brazil. Information about the production of high quality seedlings is essential for the implementation and the renewal of orchards. The objective was to evaluate protected environments and substrates for Achachairu seedlings. Two protected environments were evaluated, one covered with aluminized thermal reflector screen of 50% of shading and the other with Sombrite® of 50% of shading. Inside the protected environments were tested substrates derived from combinations of various proportions of cattle manure (CM), ravine soil (RS), medium vermiculite (MV), super fine vermiculite (FV) and sand (S). For each protected environment was adopted a completely randomized design with 5 replications of 5 seedlings. Protected environments were compared by analysis of groups of experiments. All substrates studied formed high quality seedlings for the implementation of Garcinia orchards, with low rates of aerial and root phytomasses, low rates between height and stem diameter, providing higher Dickson quality index. The Aluminet® promoted the best seedlings with larger shoot, root and total dry mass.

Anacardium occidentale L. Anacardiaceae, known as cashew, commonly found in northeastern of Brazil, has high levels of secondary metabolites, particularly tannins, used as raw material for herbal medicines. An efficient alternative to decontaminate plant products is the total sterilization or reduction of the initial microbial count, the process of gamma irradiation with 60Co. The objective of this study was to analyze the antimicrobial activity of crude extracts of bark and leaves of A. occidentale, based on the quantification of total phenols and tannins, before and after exposure to gamma radiation from 60Co. The extracts were obtained in the laboratory by cold maceration in ethanol, filtered and dryness. They were divided into non-irradiated control group (0 kGy) and irradiated: groups exposed to gamma radiation at doses of 5, 7.5 and 10 kGy. The total phenols was obtained by the Folin-Ciocalteau method and tannins, by the precipitation of casein. The antimicrobial potential activities of these extracts were also evaluated. The results showed that gamma radiation doses employed in this study did not influence statistically the percentage of total phenols and tannins in the bark extracts, at levels ranging from 5.73±0.14 and 5.20±0.14, respectively. The levels of metabolites in the leaves were statistically (p<0.05) influenced by radiation, observed average total phenols between 3.13±0.04 (0 kGy) and 3.50±0.08 (10 kGy), and tannin between 2.47±0.06 (0 kGy) and 2.93±0.04 (10 kGy). The extracts of bark and leaves were active against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Enterococcus faecalis, Mycobacterium smegmatis, Candida albicans. Gamma radiation caused an increase in antimicrobial activity of extracts against Staphylococcus aureus (Gram positive), with average inhibition zones for shells: 14.33±058 (0 kGy) and 22.33±0.58 (10 kGy), and leaves: 11.33±0.58 (0 kGy) and 19.00±1.00 (10 kGy). Exposure to radiation caused changes in physical and chemical constituents of phenolic extracts of leaves of cashew, increasing levels of tannins.