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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

Estudo da viabilidade da reciclagem de biocomp?sitos ? base de polipropileno e fibras de curau?

Bispo, Sistanley Jones Lima 03 June 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T20:53:57Z No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-14T20:57:44Z (GMT) No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) / Made available in DSpace on 2016-10-14T20:57:44Z (GMT). No. of bitstreams: 1 SistanleyJonesLimaBispo_TESE.pdf: 3279866 bytes, checksum: 4e4c98181eb5b9e3145660daab8debff (MD5) Previous issue date: 2016-06-03 / Esta pesquisa apresenta uma abordagem a cerca do processo de reciclagem do polipropileno refor?ado com fibras de curau? reprocessado. Sendo uma proposta alternativa de refor?o aos comp?sitos polim?ricos. Teores de fibras de 0%, 10%, 20% e 30% foram analisados para verifica??o de suas propriedades mec?nicas comparando-as, inclusive com as propriedades do polipropileno (PP). Os biocomp?sitos granulados foram preparados em uma extrusora. Os corpos de prova foram moldados por processo de inje??o e submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s pontos e impacto. Para verifica??o de danos aos corpos de prova utilizou-se da an?lise por microscopia eletr?nica de varredura (MEV). Estes biocomp?sitos tamb?m foram submetidos a ensaios f?sico - qu?micos de ?ndice de fluidez (IF). Observou-se que os biocomp?sitos de polipropileno com 30% de fibras de curau? apresentaram maior m?dulo de elasticidade e menor resist?ncia ao impacto. Para todos os biocomp?sitos, os valores encontrados nos ensaios de tra??o para os limites de escoamento e tens?o de ruptura n?o sofreram altera??es ? medida que se adicionavam as fibras. Outros pontos relevantes foram o aumento da resist?ncia ? flex?o, a redu??o da degrada??o t?rmica das misturas polipropileno e fibras de curau?, e o n?o comprometimento de uma forma em geral, da fabrica??o dos biocomp?sitos, quando analisados por microscopia eletr?nica de varredura. / This research presents an approach about the polypropylene recycling process reinforced with curau? reprocessed fibers. As an alternative proposal reinforcement to polymeric composites. Levels of 10 %, 20 % and 30 % of fibers in the biocomposites were analyzed to check their mechanical properties comparing them, even with the properties of polypropylene (PP). Pellets biocomposites were prepared by the extrusion process, and the specimens were manufactured by injection process and subjected to mechanical tests of uniaxial tensile, three point bending and impact. To check for damage to the specimens was used to analysis by scanning electron microscopy (SEM). These biocomposites were also subjected to testing physical ? chemistry of index of fluidity (IF). It was observed that the polypropylene biocomposites with 30 % curau? fibers showed higher elastic modulus for both traction and to flexion and less resistance to impact. For all biocomposites, the values found in tensile tests to the limits of flow and maximum voltage have approximate values as they were added the curau? fibers. Another important point was increased resistance to bending in biocomposite as promoting the addition of curau? fibers and decrease as they were reprocessed also decreased thermal degradation of the polypropylene blends and curau? fibers, and no impairment of so in general, the production of biocomposites, when analyzed by scanning electron microscopy.
2

Estudo das propriedades mec?nicas de biocomp?sitos de polipropileno refor?ados com fibras naturais

Bispo, Sistanley Jones Lima 20 June 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:07Z (GMT). No. of bitstreams: 1 SistanleyJLB_DISSERT.pdf: 3362424 bytes, checksum: 30d67bc0b13dba47c7002133ab1bb63d (MD5) Previous issue date: 2011-06-20 / This research presents an approach to the addition of curau? fibers and licuri fibers in a polypropylene resin matrix, such as an alternative proposal to reinforce the polymeric composites. Fiber content of 0 %, 5 %, 10 %, and 20% were analyzed for verification of their mechanical properties comparing them, inclusive with the properties of polypropylene. The grainulated biocomposites had been prepared in an extrusora. The test bodies had been molded by injection and submitted to the mechanical essays uniaxial traction, flexion on three points, impact, in addition to thermal tests (HDT). These biocomposites had been also subjected the essay physicist-chemistry index of fluidity (IF). It was observed that the biocomposites of PP with 20% curau?, obtained bigger increase in the modulus of elasticity and a bigger reduction in the resistance to the impact. In the mechanical behavior, for all the biocomposites, these were increases in values of the limit of drainage and tension of rupture, when tested by uniaxial traction, as they added the fibers. Another important point was the increase of the resistance the flexion. It was also noted that the addition of fibers reduced the thermal degradation of the mixture natural fibers / polypropylene. / Esta pesquisa apresenta uma abordagem da adi??o de fibras de licuri e curau? em uma matriz de resina de polipropileno, essa como uma proposta alternativa de refor?o aos comp?sitos polim?ricos. Teores de fibras de 0 %, 5 %, 10 %, e 20 % foram analisados para verifica??o de suas propriedades mec?nicas comparando-as, inclusive com as propriedades do polipropileno. Os biocomp?sitos granulados foram preparados em uma extrusora. Os corpos de prova foram moldados por inje??o e submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s pontos, impacto, al?m de ensaios t?rmicos (HDT). Estes biocomp?sitos tamb?m foram submetidos a ensaio f?sico-qu?mico de ?ndice de fluidez (IF). Observou-se que os biocomp?sitos de PP com 20% curau? obteve maior aumento no m?dulo de elasticidade, e uma maior diminui??o na resist?ncia ao impacto. No comportamento mec?nico, para todos os biocomp?sitos, houve acr?scimos nos valores do limite de escoamento e tens?o de ruptura quando ensaiados por tra??o uniaxial, ? medida que se adicionavam as fibras. Outro ponto importante foi o aumento da resist?ncia ? flex?o. Verificou-se tamb?m que a adi??o de fibras reduziu a degrada??o t?rmica da mistura fibras naturais / polipropileno.

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