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Desenvolvimento de nanocompósitos poliméricos biodegradáveis a partir de pectina, amido e nanofibras de celulose
(Universidade Federal de São Carlos, 2010-09-16) Moreira, Francys Kley Vieira; Mattoso, Luiz Henrique Capparelli; https://lattes.cnpq.br/5839043594908917; https://lattes.cnpq.br/7156680316782417
The objective of this project was the preparation of biodegradable films from polymer blends of citrus pectin (PEC) and thermoplastic starch (TPS) and the modification of its mechanical properties by formation of nanocomposites with cellulose nanofibers (NCel). The project was conducted in three stages. Firstly, the nanofibers were obtained from bleached sugarcane bagasse fibers (FBC) by hydrolysis with hydrochloric (HCl) and sulfuric (H2SO4) acids. The characterizations revealed nanofibers with needle-like morphology and diameters lower than 20 nm. The thermal stability of NCel obtained with HCl was higher than H2SO4 one. In the second stage, a factionary factorial design was applied to define a suitable processing condition for TPS/PEC blends (100/0, 75/25, 50/50, 25/75 e 0/100) in a mixer Haake, with posterior microstructural and mechanical characterizations of the blends. It was defined the condition of 130ºC, 160 RPM and 4 min to processing TPS/PEC blends, which showed biphasic microstructure and mechanical strength decreased by increase of TPS content. Due to this, NCel were incorporated at concentration of 1, 5, 10 and 15% (w/w) in the processing under different mixture conditions, aiming the improvement of the mechanical performance of the TPS/PEC blend 50/50. The characterization results evidenced that water vapour permeability, tensile strength and elastic modulus of the blend were significantly improved in 48, 150 and 350%, respectively, only with 5% of NCel. The better results were obtained by use of NCel-S and mixture of the nanocomposite formulations into milling ball equipment. The study of this project evidences the great potential of the cellulose nanofibers to the improvement of the properties in biodegradable polymeric systems based in pectin and starch natural polymers.
A ética e seu lugar na natureza segundo S. Freud
(Universidade Federal de São Carlos, 2010-09-16) Piza, Adriana Toledo; Monzani, Luiz Roberto; https://lattes.cnpq.br/2036732603638197; https://lattes.cnpq.br/5987241436359033
The Freudian conception of the unconscious is based on the idea that the human beings and the human actions are essentially determined by the instincts. This notion of instinct , taken from modern biology, refers to the idea that the movements or actions of living beings are designed by fixed patterns of behaviour transmitted genetically. Our research is an attempt to find out how, in such a context, the Freudian theories explain the ethical capacity of human beings, considering such a capacity as the ability of choosing between acting out or not acting out those so-called innate patterns of behaviour. Our analysis of the Freudian texts focuses on the principal shifts of the theories developed by him along his career, trying to point out how his conceptions establish the notion of the human action, as well as how this notion is articulated in the context of the natural sciences.