Título:	Análise ambiental e técnica para a obtenção de nanocristais de celulose de bagaço da cana-de-açúcar aplicados em nanocompósitos
Autor(es):	Leão, Rosineide Miranda
Orientador(es):	Luz, Sandra Maria da
Assunto:	Avaliação de Ciclo de Vida (ACV) Nanocompósitos Cana-de-açúcar - biotecnologia agrícola Nanocristais de celulose
Data de publicação:	10-Jan-2017
Data de defesa:	22-Ago-2016
Referência:	LEÃO, Rosineide Miranda. Análise ambiental e técnica para a obtenção de nanocristais de celulose de bagaço da cana-de-açúcar aplicados em nanocompósitos. 2016. xviii, 176 f., il. Tese (Doutorado em Ciências Mecânicas)—Universidade de Brasília, Brasília, 2016.
Abstract:	The sugarcane sector in Brazil has been growing since the beginning of the 2000s, obtaining a annual production of about 654 million tonnes in 2015, making sugarcane an important agricultural residue, may generate many applications. This fact carries the use of exceeding bagasse as a source to obtain cellulose nanocrystals. Therefore, the present study aims to obtain cellulose nanocrystals technical and environmental that can be used in nanocomposites. Nanocrystals cellulose can be extracted by various methods, so the Life Cycle Assessment (LCA) is presented as the most appropriate methodology to investigate what the most viable forms of obtainment. For that, inventory of the systems involved the sugarcane and nanocrystals production. Inputs, energy and auxiliary processes such as transportation and fuel use also were quantified. The functional unit used was 1 kg of cellulose nanocrystals. Initially, were used twelve scenarios for extraction of cellulose nanocrystals that involved experimental conditions of the literature including pre-treatment and hydrolysis. These conditions allowed isolation of cellulose nanocrystals, as well as, the chemical composition of the bagasse and of each treatment phase. The fibers and cellulose nanocrystals were characterized by a range of technical (scanning electron microscopy SEM, transmission electron microscopy TEM, atomic force microscopy AFM; infrared spectroscopy Fourier transform FTIR, X-ray diffraction and thermal analysis). After obtaining of the cellulose nanocrystals, nanocomposites of acrylonitrile butadiene styrene (ABS) reinforced with 0.5, 1.0 and 1.5% cellulose nanocrystals were obtained by extrusion. Furthermore, the influence of cellulose nanocrystals content in the nanocomposites was studied by (X-ray diffraction, TGA-thermogravimetric analysis, DSC-differential scanning calorimetry and DMA-dynamic mechanical analysis), mechanical testing, SEM and rheology. The results showed that in all scenarios in the pre-treatment phase and nanocrystals production was there was a great contribution to that contributed to environmental impacts due amounts chemicals used, and especially the high consumption of water and energy. The chemical composition of the bagasse mass was 39% of cellulose, 21% of hemicellulose and 27% of lignin. However, the SEM characterization showed that the treatment changed the morphology of the fibers, as well as, increased surface roughness. The TEM characterization showed lenght around 44-300 nm and a diameter of 10-30 nm. The AFM characterization showed the morphology of the crystallites and agglomerates. The FTIR spectra analysis clearly identified, band in 890-1364 cm-1 characteristic of cellulose I. And, finally X-ray diffraction analysis showed that the crystallinity increased with successive treatments, resulting in nanocrystals with crystallinity, about 67%. X-rays show decreased angle for nanocomposites, showing the load dispersion in the matrix. The TGA curves showed that the insertion of the nanocrystal caused a intermediate in thermal stability for the nanocomposite, and the DSC curves for nanocomposites showed thermal events similar to the ABS. The DMA curves showed increased storage modulus of the nanocomposites. The addition of the cellulose nanocrystals to ABS occurs alteration in polymer properties, statistically confirmed. Thus, depending on the application, each material will have a performance tensile higher; flexural; impact, stability; viscosity or environmental.
Unidade Acadêmica:	Faculdade de Tecnologia (FT) Departamento de Engenharia Mecânica (FT ENM)
Informações adicionais:	Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2016.
Programa de pós-graduação:	Programa de Pós-Graduação em Ciências Mecânicas
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
DOI:	http://dx.doi.org/10.26512/2016.08.T.22149
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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