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Previous issue date: 2006-02-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Sisal is a renewable agricultural resource adapted to the hostile climatic and soil conditions particularly encountered in the semi-arid areas of the state of Rio Grande do Norte. Consequently, sisal has played a strategic role in the economy of the region, as one of few options of income available in the semi-arid. Find new options and adding value to products manufactured from sisal are goals that contribute not only to the scientific and technological development of the Northeastern region, but also to the increase of the family income for people that live in the semi-arid areas where sisal is grown. Lignocellulosic fibers are extracted from sisal and commonly used to produce both handcrafted and industrial goods including ropes, mats and carpets. Alternatively, addedvalue products can be made using sisal to produce alumina fibers (Al2O3) by biotemplating, which consists in the reproduction of the natural fiber-like structure of the starting material. The objective of this study was to evaluate the conditions necessary to convert sisal into alumina fibers by biotemplating. Alumina fibers were obtaining after pretreating sisal fibers and infiltrating them with a Al2Cl6 saturated solution, alumina sol from aluminum isopropoxide or aluminum gas. Heat-treating temperatures varied from 1200 ?C to 1650 ?C. The resulting fibers were then characterized by X-ray diffraction and scanning electronic microscopy. Fibers obtained by liquid infiltration revealed conversion only of the surface of the fiber into α-Al2O3, which yielded limited resistance to handling. Gas infiltration resulted in stronger fibers with better reproduction of the inner structure of the original fiber. All converted fibers consisted of 100% α-Al2O3 suggesting a wide range of technological applications especially those that require thermal isolation / O sisal ? um recurso estrat?gico para a regi?o Nordeste e, particularmente, para o estado do Rio Grande do Norte, por ser uma cultura renov?vel e adaptada ?s condi??es do semi-?rido. Em virtude das condi??es adversas de clima e solo, o sisal ?, em algumas regi?es, o ?nico produto agr?cola rent?vel pass?vel de plantio. Agregar valor aos produtos manufaturados a partir do sisal contribui n?o s? para o desenvolvimento cient?fico e tecnol?gico da regi?o, como tamb?m para a gera??o de renda das popula??es dos munic?pios potiguares produtores de sisal. Da planta, obtem-se fibras ligninocelul?sicas utilizadas na produ??o artesanal de cordas e industrial de mantas e tapetes. Uma alternativa ? o aproveitamento da estrutura da fibra para a produ??o de fibras de alumina (Al2O3) pelo processo de biomodelagem, que consiste na reprodu??o da estrutura natural do material de partida e convers?o qu?mica de sua composi??o. Os objetivos deste projeto foram avaliar o potencial de convers?o do sisal em alumina por biomodelagem. Os m?todos utilizados foram infiltra??es com solu??o de cloreto de alum?nio, solu??o sol-gel de alumina utilizando como precursor isoprop?xido de alum?nio e infiltra??o de alum?nio gasoso, para obten??o final das fibras de alumina. As temperaturas de sinteriza??es variaram de 1200 ?C a 1650 ?C. As caracteriza??es das fibras de alumina foram realizadas atrav?s de difra??o de raios X e microscopia eletr?nica de varredura. Para as fibras obtidas por infiltra??o liquida, os resultados mostraram a convers?o completa apenas da superf?cie da fibra de sisal em α-Al2O3, resultando em baixa resist?ncia ao manuseio. O m?todo de infiltra??o de alum?nio gasoso resultou em fibras com melhor reprodu??o da estrutura interna do sisal. O potencial tecnol?gico de aplica??o das fibras e mantas estende-se a aplica??es que requerem propriedades t?rmicas, especificamente isolamento t?rmico, j? que a composi??o qu?mica final das fibras foi 100% α-Al2O3
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/12810 |
| Date | 21 February 2006 |
| Creators | Andrade J?nior, Tarc?sio El?i de |
| Contributors | CPF:15724520800, http://lattes.cnpq.br/0022988322449627, Rambo, Carlos Renato, CPF:13474819828, http://lattes.cnpq.br/3603011798628583, Santos, I?da Maria Garcia dos, CPF:50548220115, http://lattes.cnpq.br/7060067415685353, Nascimento, Rubens Maribondo do, CPF:80732810400, http://lattes.cnpq.br/8671649752936793, Melo, Marcus Ant?nio de Freitas, CPF:04514998320, http://lattes.cnpq.br/5840621182000517, Melo, Dulce Maria de Ara?jo, Martinelli, Ant?nio Eduardo |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncia e Engenharia de Materiais, UFRN, BR, Processamento de Materiais a partir do P?; Pol?meros e Comp?sitos; Processamento de Materiais a part |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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