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Mechanical caracterisation of polyester and sunflower natural fiber composite

Rocha, João; Queijo, Luís
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Conferência ou Objeto de Conferência
POR
Relevância na Pesquisa
56.29%
The use of natural fibers as reinforcement in polymer matrix composites is gaining popularity in the development of renewable products. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. This work deals with the characteristics of natural fiber composites that can offer several advantages, like low cost, weight savings and relatively good mechanical properties. It focuses on the effects of sunflower fibers as reinforcement agents in composites. Mechanical testing of Sunflower natural fibers composite was performed to qualify and quantify the reinforcement properties. At same time, Glass fiber composite sample tests have been produced and characterized and both results have been compared. From results comparison we can affirm that the produced polymeric sunflower fiber composite has adequate mechanical properties for lots of industrial applications even, as expected, these are lower than glass fiber composites. Using this natural fiber content this product become a more ecological substitute and environment friendly that the traditional polymeric glass fiber composites. For other way, once stems from sunflower plants are wastes that traditionally are left in the field...

Mechanical caracterisation of polyester and sunflower natural fiber composite

Rocha, João; Queijo, Luís
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.29%
The use of natural fibers as reinforcement in polymer matrix composites is gaining popularity in the development of renewable products. Although glass and other synthetic fiber-reinforced plastics possess high specific strength, their fields of application are very limited because of their inherent higher cost of production. This work deals with the characteristics of natural fiber composites that can offer several advantages, like low cost, weight savings and relatively good mechanical properties. It focuses on the effects of sunflower fibers as reinforcement agents in composites. Mechanical testing of Sunflower natural fibers composite was performed to qualify and quantify the reinforcement properties. At same time, Glass fiber composite sample tests have been produced and characterized and both results have been compared. From results comparison we can affirm that the produced polymeric sunflower fiber composite has adequate mechanical properties for lots of industrial applications even, as expected, these are lower than glass fiber composites. Using this natural fiber content this product become a more ecological substitute and environment friendly that the traditional polymeric glass fiber composites. For other way, once stems from sunflower plants are wastes that traditionally are left in the field...

Fracture and fatigue of natural fiber-reinforced cementitious composites

SAVASTANO JR., H.; SANTOS, S. F.; RADONJIC, M.; SOBOYEJO, W. O.
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.02%
This paper presents the results of an experimental study of resistance-curve behavior and fatigue crack growth in cementitious matrices reinforced with eco-friendly natural fibers obtained from agricultural by-products. The composites include: blast furnace slag cement reinforced with pulped fibers of sisal, banana and bleached eucalyptus pulp, and ordinary Portland cement composites reinforced with bleached eucalyptus pulp. Fracture resistance (R-curve) and fatigue crack growth behavior were studied using single-edge notched bend specimens. The observed stable crack growth behavior was then related to crack/microstructure interactions that were elucidated via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Fracture mechanics models were used to quantify the observed crack-tip shielding due to crack-bridging. The implications of the results are also discussed for the design of natural fiber-reinforced composite materials for affordable housing. (C) 2009 Elsevier Ltd. All rights reserved.; Division of Civil and Mechanical Systems (CMS); Division of Materials Research of the National Science Foundation (NSF)[CMS 0303492]; Division of Materials Research of the National Science Foundation (NSF)[DMR 0231418]; National Council for Scientific and Technological Development (CNPq); Co-ordination for the Improvement of Higher Education Personnel (Capes)

Fracture and resistance-curve behavior in hybrid natural fiber and polypropylene fiber reinforced composites

Tan, T.; Santos, S. F.; Savastano, H., Jr.; Soboyejo, W. O.
Fonte: SPRINGER; NEW YORK Publicador: SPRINGER; NEW YORK
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.15%
This article presents the results of a combined experimental and theoretical study of fracture and resistance-curve behavior of hybrid natural fiber- and synthetic polymer fiber-reinforced composites that are being developed for potential applications in affordable housing. Fracture and resistance-curve behavior are studied using single-edge notched bend specimens. The sisal fibers used were examined using atomic force microscopy for fiber bundle structures. The underlying crack/microstructure interactions and fracture mechanisms are elucidated via in situ optical microscopy and ex-situ environmental scanning microscopy techniques. The observed crack bridging mechanisms are modeled using small and large scale bridging concepts. The implications of the results are then discussed for the design of eco-friendly building materials that are reinforced with natural and polypropylene fibers.; Princeton University; Princeton University; Division of Civil and Mechanical Science Foundation [CMS 0303492]; Division of Civil and Mechanical Science Foundation; Division of Materials Research of the National Science Foundation; Division of Materials Research of the National Science Foundation [DMR 0231418]; Brazilian agency FAPESP; Brazilian agency Fapesp [Fapesp 2010/16524-0]; Brazilian agency CNPq; Brazilian agency CNPq [CNPq. 305792/2009-1]

Preparation and characterization of ramie-glass fiber reinforced polymer matrix hybrid composites

Romanzini, Daiane; Ornaghi Junior, Heitor Luiz; Amico, Sandro Campos; Zattera, Ademir José
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
46.19%
The use of ramie fibers as reinforcement in hybrid composites is justified considering their satisfactory mechanical properties if compared with other natural fibers. This study aims to verify changes in chemical composition and thermal stability of the ramie fibers after washing with distilled water. One additional goal is to study glass fiber and washed ramie fiber composites focusing on the effect of varying both the fiber length (25, 35, 45 and 55 mm) and the fiber composition. The overall fiber loading was maintained constant (21 vol.%). Based on the results obtained, the washed ramie fiber may be considered as an alternative for the production of these composites. The higher flexural strength presented being observed for 45 mm fiber length composite, although this difference is not significant for lower glass fiber volume fractions: (0:100) and (25:75). Also, by increasing the relative volume fraction of glass fiber until an upper limit of 75%, higher flexural and impact properties were obtained.

Natural fiber reinforced unsaturated polyester composites - An approach on compression molding

Giacomini, Nestor Pedro; Knothe, Jürgen; Neto, Octavio Pimenta Reis; Leao, Alcides Lopes
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
56.21%
This work has been performed at Tapetes Sao Carlos-Brazil with the cooperation of the DaimlerChrysler Research Center Team in Ulm - Germany. The objective of the present paper is to report the results obtained with natural fiber reinforced unsaturated polyester (UP) composites, concerning surface quality measurements. The fibers that have been chosen for this work were sisal and curaua. The samples were produced by compression molding technique and afterwards submitted to three different tests, namely: a) thermal aging; b) water absorption and c) artificial weathering. The surface parameters measured before and after the tests were gloss, haze, short and long-waviness. The results have shown that after the tests there is a high loss of gloss, a high increase in haze, and a high increase in short and long-waviness as well. Curaua reinforced composites had a slightly better behavior when compared with sisal reinforced composites. The effect of the presence of filler and the addition of thermoplastic polyester (TP) on the material behavior has not been evidently detected. This result shows that the conventional technology/methods applied to UP-Fiberglass systems cannot be transferred to natural fibers without any modification. The fiber-matrix interaction and its response to the presence of additives must be fully understood before a successful processing route can be developed for painted natural fibers reinforced UP. Copyright © 2001 Society of Automotive Engineers...

Biocompósitos poliméricos de poli(butileno adipato-co-tereftalato) : PBAT e fibra natural de Munguba, nativa da Amazônia (Pseudobombax munguba); Polymeric biocomposites of poly(butylene adipate-co-terephthalate) : PBAT and Munguba (Pseudobombax munguba), a natural fiber native from Amazônia

Ivanei Ferreira Pinheiro
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 10/07/2012 PT
Relevância na Pesquisa
56.32%
Neste trabalho estudou-se biocompósitos poliméricos obtidos a partir de um poliéster biodegradável e fibra natural de Munguba (Pseudobombax munguba) nativa da região amazônica. Trata-se de uma fibra de grande abundância encontrada nas regiões alagadiças da floresta, para a qual não existem relatos na literatura de sua utilização em biocompósitos poliméricos. Estudou-se a influência do tamanho da fibra, da concentração, e de tratamentos químicos na superfície da fibra, sobre as propriedades finais dos biocompósitos. As fibras naturais foram moídas e classificadas por tamanho e submetidas a tratamentos químicos. A fim de avaliar as modificações promovidas pelos tratamentos empregados, as propriedades mecânicas, morfologia e propriedades de superfície foram analisadas. A análise por Espectroscopia no Infravermelho (FTIR) mostrou o aparecimento de grupos ésteres confirmando a troca de hidroxila por acetila. Os ensaios mecânicos de tração mostraram que a modificação química proporcionou aumento de 75% no módulo elástico da fibra. Pelas análises de morfologia e de ângulo de contato, foram verificadas alterações superficiais significativas da fibra de munguba, enquanto que a análise termogravimétrica (TGA) mostrou que a modificação química aumentou a estabilidade térmica em comparação com a fibra natural. Os biocompósitos foram preparados por mistura em alto cisalhamento no estado fundido...

Fibras naturais como matéria-prima para a produção de carvão ativado; Natural fibers as raw material for the production of activated carbon

Carla Fabiana Scatolim Rombaldo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/06/2015 PT
Relevância na Pesquisa
46.19%
As fibras obtidas diretamente de fonte animal, mineral e vegetal são definidas como fibras naturais, sendo as mais comuns: a lã, o linho, o rami, o sisal, a juta, entre outras. Essas fibras têm uma importância social muito forte em países tropicais, especialmente na geração de empregos na zona rural e em áreas economicamente deprimidas. As fibras naturais, em sua maioria, são leves, resistentes, não abrasivas, renováveis, biodegradáveis e recicláveis, características que permitem competir com outros materiais artificiais que tenham problemas de disponibilidade ou ambientais. Além dos compósitos desenvolvidos com fibras naturais, existem ainda os carvões ativados que se destacam como um material com elevada porosidade e alta capacidade de adsorção, tanto em fase liquida quanto em fase gasosa. Visando o aproveitamento de recursos naturais disponíveis no território nacional e buscando alternativas que sejam economicamente viáveis para a produção de carvão ativado (CA), o presente trabalho teve como objetivo geral utilizar as fibras de juta e as fibras de sisal como matérias-primas para a produção de CA. Os CAs produzidos foram testados para a remoção de benzeno em solução aquosa. A produção do CA foi baseada na carbonização e na ativação física com CO2 e vapor d¿água. Para avaliar a evolução da estrutura porosa dos CAs obtidos foi utilizada a técnica de adsorção de N2 a 77K. Os resultados indicaram a possibilidade de produzir um material poroso com uma combinação de estrutura micro e mesoporosa...

Experimental study on natural fiber composites for strengthening of masonry

Codispoti, R.; Oliveira, Daniel V.; Fangueiro, Raúl; Olivito, R.; Lourenço, Paulo B.
Fonte: AIAS Publicador: AIAS
Tipo: Conferência ou Objeto de Conferência
Publicado em 21/12/2012 ENG
Relevância na Pesquisa
56.22%
In the present paper the first results obtained from a vast experimental investigation carried out on natural fiber composite materials (flax, hemp, jute, sisal and coir) are reported. Tensile tests on single yarns and fabrics have been carried out according to the current standards. Two types of matrices have been used: polymeric and mortar-based matrices. Therefore, the composites materials NFRP (Natural Fiber Reinforced Polymer) and NFRG (Natural Fiber Reinforced Grout) have been obtained. A new fiber placement technology has been studied, the so-called "braiding technology", in order to increase the mechanical properties of the natural non-impregnated materials. The results obtained, were compared with those of the most common composites systems (CFRP and GFRP).

Experimental behavior of natural fiber-based composites used for strengthening masonry structures

Codispoti, Rosamaria; Oliveira, Daniel V.; Fangueiro, Raúl; Lourenço, Paulo B.; Olivito, Renato S.
Fonte: Hindawi Publicador: Hindawi
Tipo: Artigo de Revista Científica
Publicado em //2013 ENG
Relevância na Pesquisa
56.21%
This paper deals with the experimental characterization of the tensile behavior of fiber-based composites and flexural strength of natural fiber reinforced polymer (NFRP) sheets externally glued on masonry bricks, in terms of load capacity and stress distribution along the bonded length. The bricks adopted for this experimentation are solid clay bricks, typically used in ancient masonry structures. Non-impregnated and impregnated flax, hemp, jute and sisal fibers were examined. Two types of matrices have been used: polymer matrices and mortar- based matrices. Composite materials defined as NFRP (Natural Fiber Reinforced Polymer) and NFRG (Natural Fiber Reinforced Grout) were obtained.

Estudo da degradação de geotêxteis em fibra natural; Study of the degradation of natural fiber geotextiles

Costa, José Eduardo Gonçalves
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2013 POR
Relevância na Pesquisa
56.14%
Dissertação de mestrado integrado em Engenharia Civil (área de especialização em Perfil de Construções); A sociedade atual sente cada vez mais a necessidade de procurar soluções eficientes e sustentáveis para os problemas do dia-a-dia. Sendo o setor da construção civil um dos grandes responsáveis pela exploração de recursos e emissão de gases poluentes, fruto da sua atividade, torna-se necessário a alteração de algumas das práticas atuais. Os geotêxteis usados em diversas aplicações, como por exemplo, controlo da erosão de taludes, reforço ou drenagem de solos em obras de engenharia são quase exclusivamente compostos por materiais sintéticos. A consideração de geotêxteis de fibras naturais, especialmente quando o período funcional requerido a um geotêxtil é de apenas alguns meses, torna-se a solução ideal devido ao facto de estes serem biodegradáveis e constituídos por recursos renováveis, sendo ambientalmente mais sustentáveis que os seus semelhantes sintéticos. Esta dissertação pretende contribuir para o aprofundamento do conhecimento sobre a viabilidade da consideração de fibras naturais de origem vegetal como geotêxteis, nomeadamente o seu comportamento mecânico e estrutura fibrosa...

Brazilian natural fiber (jute) as raw material for activated carbon production

ROMBALDO,CARLA F.S.; LISBOA,ANTONIO C.L.; MENDEZ,MANOEL O.A.; COUTINHO,APARECIDO R.
Fonte: Academia Brasileira de Ciências Publicador: Academia Brasileira de Ciências
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 EN
Relevância na Pesquisa
46.12%
Jute fiber is the second most common natural cellulose fiber worldwide, especially in recent years, due to its excellent physical, chemical and structural properties. The objective of this paper was to investigate: the thermal degradation of in natura jute fiber, and the production and characterization of the generated activated carbon. The production consisted of carbonization of the jute fiber and activation with steam. During the activation step the amorphous carbon produced in the initial carbonization step reacted with oxidizing gas, forming new pores and opening closed pores, which enhanced the adsorptive capacity of the activated carbon. N2 gas adsorption at 77K was used in order to evaluate the effect of the carbonization and activation steps. The results of the adsorption indicate the possibility of producing a porous material with a combination of microporous and mesoporous structure, depending on the parameters used in the processes, with resulting specific surface area around 470 m2.g–1. The thermal analysis indicates that above 600°C there is no significant mass loss.

Preparation and characterization of ramie-glass fiber reinforced polymer matrix hybrid composites

Romanzini,Daiane; Ornaghi Junior,Heitor Luiz; Amico,Sandro Campos; Zattera,Ademir José
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2012 EN
Relevância na Pesquisa
46.19%
The use of ramie fibers as reinforcement in hybrid composites is justified considering their satisfactory mechanical properties if compared with other natural fibers. This study aims to verify changes in chemical composition and thermal stability of the ramie fibers after washing with distilled water. One additional goal is to study glass fiber and washed ramie fiber composites focusing on the effect of varying both the fiber length (25, 35, 45 and 55 mm) and the fiber composition. The overall fiber loading was maintained constant (21 vol.%). Based on the results obtained, the washed ramie fiber may be considered as an alternative for the production of these composites. The higher flexural strength presented being observed for 45 mm fiber length composite, although this difference is not significant for lower glass fiber volume fractions: (0:100) and (25:75). Also, by increasing the relative volume fraction of glass fiber until an upper limit of 75%, higher flexural and impact properties were obtained.

Diameter dependence of tensile strength by Weibull analysis: Part III sisal fiber

Inacio,W.P.; Lopes,F.P.D.; Monteiro,S.N.
Fonte: Rede Latino-Americana de Materiais Publicador: Rede Latino-Americana de Materiais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
46.19%
Environmental aspects and economical advantages are motivating the use of natural fiber as reinforcement of polymer composites in substitution for synthetic fiber composites such as fiber glass. In particular, the sisal fiber is one of the most investigated and being used in engineering systems. By contrast to synthetic fibers, natural fibers have the disadvantage of being heterogeneous in their dimensions specially the diameter. In several natural fibers it has been found that the smaller the diameter, the stronger is the fiber. In this work a Weibull analysis of sisal fibers tensile strength was performed to find a correlation with the diameter. The results revealed an inverse dependence of the tensile strength with the diameter. The observation of ruptured fibers by scanning electron microscopy suggested possible mechanisms that justify a hyperbolic correlation.

Effect of electron beam irradiation on mechanical properties of gelatin/Brazil nut shell fiber composites

Inamura,Patrícia Y.; Shimazaki,Kleber; Colombo,Maria Aparecida; Rosa,Ricardo de; Moura,Esperidiana Augusta Barretos de; Mastro,Nelida L. del
Fonte: Rede Latino-Americana de Materiais Publicador: Rede Latino-Americana de Materiais
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
56.1%
The use of natural fiber as polymeric matrix reinforcement has attracted interest, as fibers are renewable, of low cost, biodegradable and possesses non-toxic properties. In the present paper, Brazil nuts (Bertholletia excelsa) shell fiber (10% w/w) were mixed with gelatin (25% w/w), glycerin as plasticizer and acrylamide as copolymer to investigate the resultant mechanical properties effects upon ionizing radiation. The samples were irradiated at 40 kGy using a Dynamitron electron beam accelerator, at room temperature in the presence of air. The results showed that samples of gelatin with 10% of Brazil nuts shell fiber and irradiated at 40 kGy presented promising results for mechanical performance.

Exquisite wild mushrooms as a source of dietary fiber: analysis in electron-beam irradiated samples

Fernandes, Ângela; Barreira, João C.M.; Antonio, Amilcar L.; Morales, Patricia; Férnandez-Ruiz, Virginia; Martins, Anabela; Oliveira, M.B.P.P.; Ferreira, Isabel C.F.R.
Fonte: Instituto Politécnico de Bragança Publicador: Instituto Politécnico de Bragança
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.09%
In the present study, electron-beam irradiation was applied to dried samples of Boletus edulis and Macrolepiota procera to evaluate the effects on their fiber composition. Both species presented an important percentage of dietary fiber, soluble and insoluble in different ratios. These high fiber levels are an interesting feature, allowing considering mushrooms as an alternative source of dietary fibers in the highly competitive market of fiber-enriched food products. In B. edulis samples, insoluble fiber and total fiber amounts were significantly lower in samples irradiated with 10 kGy, but soluble fiber had no significant changes for any of the assayed doses, while total available carbohydrates were significantly lower in unirradiated samples. M. procera samples irradiated with 6 kGy presented less total fiber, insoluble fiber and carbohydrates, but the same dose allowed the highest contents in soluble dietary fiber. In general, the irradiated samples, especially for higher doses, gave some significant changes in the total available carbohydrates and dietary fibers content. Nevertheless, the resulting differences still allow considering these species as good natural fiber sources, maintaining their potential health effects, while promoting a clean way to disinfest and decontaminate these highly perishable products.; Authors are grateful to the Foundation for Science and Technology (FCT...

THE EFFECTS OF FIRE RETARDANT ADDITIVES ON THE PROPERTIES OF FLAX FIBER BIO-RESIN COMPOSITES AT ROOM AND ELEVATED TEMPERATURES

Budd, Ryan
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
56.15%
Today, throughout the engineering world, there is a large emphasis being placed on the environment which requires the development of new greener materials. This is no different in the realm of composite materials with natural fibers and new bio-based resins being investigated to replace their synthetic alternatives. However, a large obstacle has prevented a more wide spread use of green Natural Fiber Reinforced Polymer (NFRP) materials, and that is their poor elevated temperature (ET) and fire performance. One common method for increasing the fire performance of a material is the incorporation of fire retardant (FR) additives. The purpose of this research was to investigate, and try to maximize, the ET properties of new NFRP composites. Specifically, this included evaluating the mechanical properties of NFRP composites at room temperature (RT) and ET, as well as assessing the effect of FR additives on these properties. A secondary goal of this research included comparing a synthetic epoxy resin, Biresin, with a bio-based epoxy resin, Super Sap. This was accomplished using one type of natural fiber (flax), two resins (one synthetic, one bio-based) and three FR additives. In all, four different testing methods were employed. The first was Differential Scanning Calorimetry (DSC) analysis of all composite materials. The second type of testing evaluated the resin plus additive combinations without any fibers. The final two types of testing evaluated the mechanical properties of the fabricated NFRP at RT and ET. Several important conclusions were reached with regards to this research. One of these noted the percentage loadings used in this research did not negatively affect the NFRP samples enough to be considered a major hindrance against their use in NFRP fabrication. It was also determined Super Sap composites could be used as an appropriate replacement for Biresin FRP composites in high temperature applications. Finally...

Desenvolvimento e caracterização de um composito hibrido de polipropileno homopolimero e micro fibra de silica amorfa e fibra de madeira, utilizando agente de acoplagem; Development and characterization of a hybrid composites polypropylene homopolymer and micro fiber amorphous silica and powder´s wood using coupling agents

Alex Kazuo Sato
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 03/12/2008 PT
Relevância na Pesquisa
46.12%
Um dos grandes desafios que enfrentamos neste novo século de avanços tecnológicos é o desenvolvimento de novos materiais que atendam as necessidades pré-requeridas no que diz respeito às propriedades mecânicas e térmicas das peças e seu custo, reunindo assim uma excelente relação de custo beneficio. Este trabalho visou o estudo de um compósito híbrido termoplástico, usando polipropileno como matriz polimérica associado a uma micro fibra de sílica amorfa (MFSA) e uma fibra natural originada da madeira, para se testar a viabilidade de sua utilização na área dos materiais de engenharia. Foram testadas várias formulações com diferentes proporções de MFSA e de fibra de madeira, bem como compósitos com e sem agentes de acoplamento, funcionalizados com anidrido maleico. A eficiência desses agentes e as propriedades térmicas, mecânicas e morfológicas das diferentes formulações foram avaliadas por meio de testes de resistência à tração, impacto Izod, dureza Shore D, HDT, Vicat e por calorimetria e microscopia eletrônica de varredura dos compósitos obtidos. Os resultados mostraram que o compósito híbrido de homo polipropileno carregado como micro fibra de sílica amorfa e fibra de madeira, auxiliada com o agente de acoplagem estudado...

Durabilidade de fibrocimento reforçado com polpa de sisal após 10 anos de envelhecimento natural

Farrapo, Camila Laís
Fonte: Universidade Federal de Lavras; Programa de Pós-Graduação em Engenharia de Biomateriais; UFLA; brasil; Departamento de Ciências Florestais Publicador: Universidade Federal de Lavras; Programa de Pós-Graduação em Engenharia de Biomateriais; UFLA; brasil; Departamento de Ciências Florestais
Tipo: Dissertação
Publicado em 04/12/2015 POR
Relevância na Pesquisa
46.24%
Cementitious materials are typically characterized by their brittle trait. Thus, the insertion of fibers as reinforcement improves the composite’s energy absorption. The conventional material used as reinforcement for fiber cement is asbestos. However, global tendency is to review the use of this mineral fiber. The use of natural fibers as reinforcement in fiber cement generates high expectations, but the durability of this type of composite is still a challenge. Thus, this work aimed at assessing the effect of several techniques (addition of synthetic fibers, carbonation and autoclaving) to increase the durability of reinforced roofing tiles with sisal pulp. The roofing tiles were produced by means of vacuum-pressure process, used to evaluate the percentage of sisal pulp in association or not with polypropylene fibers, as well as the effect of carbonation and autoclaving over the durability of cement composites. The natural aging of the roofing tiles was done over a 10-year period, in the municipality of Pirassununga, São Paulo, Brazil. We evaluated physical, mechanical and microstructural properties after such period...

Determination of optimal alkaline treatment conditions for fique fiber bundles as reinforcement of composites materials

Castro,Cristina; Palencia,Ana; Gutiérrez,Iván; Vargas,Gustavo; Gañán,Piedad
Fonte: Facultad de Ingeniería, Universidad del Zulia Publicador: Facultad de Ingeniería, Universidad del Zulia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2007 EN
Relevância na Pesquisa
46.18%
For the last decades, natural fibers have been used as reinforcement of friendly environmental polymeric composites, due to their technical, economical and environmental advantages that include: moderate mechanical and thermal properties. However, the OH groups in some of their chemical structures like cellulose, reduce the compatibility with hydrophobic polymeric matrices such as polyolefines. Natural fiber, usually are exposed to chemical and physical treatment to reduce their hydrophilic tendency and to enhance fiber/matrix adhesion. Alkalinization, alkali treatment or mercerization, is one of the most common procedures applied on natural fibers. This process introduces important changes on its mechanical properties, physical and morphological characteristics, and chemical composition. In spite of other studies, it is necessary define surface treatment conditions in accordance with industrial processing and environmental considerations. In this study, the influence of different alkali treatment conditions on the fique fiber tensile behavior has been evaluated. Treatment parameters as solution concentration, exposure time and dry conditions have been analyzed. Fourier transformation infrared spectrophotometry (FTIR) analysis, atomic force (AFM) and optical microscopies have been used to evaluate alteration on chemical and morphological characteristics. Treatment conditions that include low solution concentration bring a good enough quality in the mechanical behavior required by fique fiber bundles as polymeric reinforcement