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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

INNER FORM - OUTER HONESTY

WEST, CARL 14 July 2005 (has links)
No description available.
2

PreparaÃÃo de novos compÃsitos suportados em matriz de fibra vegetal/natural. / Preparation of new composites of phenolic resin (matriz) in natural/vegetal fibers

Milena Alencar Esmeraldo 10 March 2006 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Nos Ãltimos anos, houve um acelerado desenvolvimento na Ãrea de compÃsitos reforÃados por fibras naturais, como (juta, sisal, coco, linho etc.) Fibras naturais sÃo uma importante alternativa, pois apresentam as seguintes vantagens: abundÃncia, biodegrabilidade, baixo peso, regenerabilidade, nÃo sÃo tÃxicas, apresentam baixo custo de aplicaÃÃo comparado com as fibras sintÃticas e podem ser modificadas por tratamento quÃmico. O presente trabalho teve por objetivo a preparaÃÃo e caracterizaÃÃo de compÃsitos suportados, em matriz fenÃlica derivadas do LCC, reforÃados por fibras naturais de coco e juta. Foram conduzidas modificaÃÃes superficiais nas fibras atravÃs de tratamento alcalino (mercerizaÃÃo) NaOH nas concentraÃÃes 5% e 10% (75 0C) e branqueamento com hipoclorito de sÃdio (NaClO/H20 1:1) (60 0C). Os compÃsitos foram preparados por moldagem aberta com fibras de coco e juta para todos os tratamentos. As propriedades mecÃnicas, tÃrmicas, dielÃtricas bem como as investigaÃÃes superficiais das fibras antes e apÃs o tratamento quÃmico e interface dos compÃsitos foram investigados pelas tÃcnicas de ensaios de traÃÃo (elongaÃÃo à ruptura, mÃdulo elÃstico, resistÃncia à ruptura); TG/DTG (Termogravimetria/Derivada); DSC (Calorimetria ExploratÃria Diferencial); DRX (Difratograma de Raios X); propriedades dielÃtricas, (Perda DielÃtrica, Condutividade DielÃtrica) e MEV (Microscopia de Varredura EletrÃnica). Fibras de coco, juta e compÃsitos apresentaram um aumento global das propriedades mecÃnicas apÃs o tratamento quÃmico com NaOH 5% e 10% .Os melhores resultados foram aqueles observados para os compÃsitos de juta apÃs tratamento com NaOH 5% onde se observou um aumento de 28% na resistÃncia à ruptura, jà para os compÃsitos de coco os melhores resultados foram os apÃs tratamento com NaOH 10% com aumento de 48%. Os resultados de anÃlise termogravimÃtrica em atmosfera inerte mostraram processos de estabilidade tÃrmica para as fibras e compÃsitos apÃs o II tratamento quÃmico com NaOH 5% e 10 % respectivamente. Para as fibras de juta observou-se um aumento de (218-228 0C) para as de coco o aumento foi de (259- 276 0C). Os compÃsitos de juta e coco tambÃm apresentaram um aumento na estabilidade tÃrmica apÃs o tratamento quÃmico, onde os melhores resultados obtidos foram: compÃsitos de juta (302-3060C) apÃs tratamento com NaOH 5%, e os de coco (288-310 0C) apÃs tratamento com NaOH 10%. Esses resultados comprovaram que o tratamento alcalino de fato proporcionou uma melhora da estabilidade tÃrmica dos compÃsitos. As anÃlises de investigaÃÃo superficial das fibras de juta e coco apresentaram claramente modificaÃÃes estruturais como conseqÃÃncia da remoÃÃo parcial de constituintes apÃs o tratamento quÃmico. Para os compÃsitos dessas fibras, foi observado que apÃs o tratamento quÃmico, com a remoÃÃo de componentes nÃo celulÃsicos, ocorreu de fato uma melhor adesÃo, ou seja, interface agente de reforÃo/matriz fenÃlica. / In recent years there was a rapid development in the field of composites reinforced by natural fibers like (jute, sisal, coir, hemp etc). Natural fibers are an important alternative, offering several advantages such their abundant, biodegrability, light weight, renewability, are not toxic, presents low cost application compared with synthetic fibers and may be easily modified by chemical treatment. The present work aimed the study, preparation and characterization of composites of phenolic resin (matriz) based on CNSL, reinforced by natural fibers of coir and jute. Superficial modification on the fibers were carried out through alkali treatment (mercerization) NaOH 5% and NaOH 10% (75 0C) and bleaching with sodium hipoclorite (NaClO/H20 1:1) (60 0C). All the fibers composites were prepared by open mold. The composites and fibers were characterized by analysis techniques such mechanical tensile strength (elongation at break, youngâs modulus, resistant at break); TG/DTG (Thermogravimetry); DSC (Differential Scanning Calorimetric); DRX (Difractrogram X - Ray); dielectric properties (Dielectric Conductivity, Dielectric Loss) and SEM (Scanning Electron Microscopy) investigation on the surface modification in fibers and composites after chemical treatment. The results to coir and jute fibers composites showed an increase of mechanical properties. The best mechanical performance was generally obtained for composites of jute and coir after NaOH 5% and NaOH 10% showing an enhancement of mechanical properties resistant at break (28%) and (48%) respectively. IV The thermal degradation behavior of composites and coir - jute fibers under a nitrogen atmosphere showed an increase of thermal stability after alkaline treatment NaOH 5% e 10 % compared with untreated fibers. To jute fibers it was observed an improvement of (218-228 0C) to coir fibers this increased it was (259- 276 0C). The same thermal stability was evaluated to composites of theses fibers after alkaline treatment NaOH 5% and NaOH 10%. To jute fibers composites the best results were (302-3060C) while coir composites were (288-310 0C). From the results obtained, it is possible to conclude that alkaline treatment contribute to significant improvement of thermal behaviour of the composites The SEM investigation showed significant improvement on surfaces of jute and coir fibers after chemical treatment. The alkali treatment, removed non-celluloic components from fibers surface, expoding their internal fibrillar structure. As a consequence the treatment promoted an increase on interfacial adhesion between coir and jute fibers reinforced phenolic resin composite.
3

INCORPORATION OF BIO BASED FLAX FIBER REINFORCED POLYMER SKINS FOR PACKAGING ENHANCEMENTS

Sufia Suleman Sukhyani (11679325) 20 December 2021 (has links)
This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.
4

Incorporation of Bio Based Flax Fiber Reinforced Polymer Skins for Packaging Enhancements

Sukhyani, Sufia 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.

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