Sabiia Seb
PortuguêsEspañolEnglish
Embrapa
        Busca avançada

Botão Atualizar


Botão Atualizar

Ordenar por: RelevânciaAutorTítuloAnoImprime registros no formato resumido
Registros recuperados: 17
Primeira ... 1 ... Última
Imagem não selecionada

Imprime registro no formato completo
A multi-scale study of the interface between natural fibres and a biopolymer ArchiMer
Le Duigou, Antoine; Baley, Christophe; Grohens, Yves; Davies, Peter; Cognard, Jean Yves; Creach Cadec, Romain; Sohier, Laurent.
A significant recent development in the composite field is the appearance of biocomposites (biopolymers reinforced by plant fibres) which combine mechanical performance and low environmental impacts. However, to replace conventional composites a significant effort is needed to understand their mechanical behaviour under complex loading (both in-plane and out-of-plane). The interfacial behaviour (fibre/matrix) of these materials also requires particular attention in order to optimize mechanical properties. With this aim modified Arcan, transverse tension and microdroplet debonding tests have been performed on flax reinforced PLLA biocomposites, as very few data of this type are available. The out-of-plane tensile and tensile-shear properties of these...
Tipo: Text Palavras-chave: A natural fibre composites; B interfacial properties; B out-of-plane properties; B microbond test.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00197/30857/29222.pdf
Imagem não selecionada

Imprime registro no formato completo
Comparison of the properties of scutched flax and flax tow for composite material reinforcement ArchiMer
Martin, Nicolas; Davies, Peter; Baley, Christophe.
The industrial production of flax fibers yields two fibrous products: scutched fibers are valuable for their length, fineness and cleanness, while tows are entangled, impure and are low-priced. There is a need for technical data to compare these two kinds of fibers beyond the difference of appearance, and to assess their potential as composite material reinforcements. In this work, we have compared the properties of scutched flax and flax tows from the same batch. The morphology was first assessed by measuring the length, cleanness and fineness of fiber bundles. The tensile properties of single fibers and of unidirectionally reinforced epoxy composites were then measured. The results show that the morphology of flax tows is different from but close to the...
Tipo: Text Palavras-chave: Flax fibers; Scutching; Flax by-products; Composite materials.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00203/31403/41240.pdf
Imagem não selecionada

Imprime registro no formato completo
Effect of recycling on mechanical behaviour of biocompostable flax/poly(L-lactide) composites ArchiMer
Le Duigou, Antoine; Pillin, Isabelle; Bourmaud, Alain; Davies, Peter; Baley, Christophe.
The biocompostability of natural fibre-reinforced biopolymers, also known as biocomposites, makes them an attractive alternative to glass fibre-reinforced petrochemical polymers. The aim of this work is to study the capacity of flax/PLLA (poly(L-lactide)) biocomposite (20% and 30% fibres by weight) to be recycled. Mechanical properties were evaluated initially, and shown to be similar to those of glass/PP and superior to hemp/PP and sisal/PP composites. Then after repeated injection cycles tensile properties were shown to be conserved until the third cycle. Matrix degradation and fibre aspect ratio were followed using molecular weight measurements, thermal and rheological analyses, image analysis of sections and SEM fractography. These techniques revealed...
Tipo: Text Palavras-chave: Mechanical properties; Recycling; Flax fibres; PLLA.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6360.pdf
Imagem não selecionada

Imprime registro no formato completo
Evaluation of the potential of three non-woven flax fiber reinforcements: Spunlaced, needlepunched and paper process mats ArchiMer
Martin, Nicolas; Davies, Peter; Baley, Christophe.
This paper presents results from an experimental study of three types of non-woven preforms (needlepunched, spunlaced and mat manufactured using a paper-making process) intended as composite reinforcement. These are potentially very attractive for transport applications. First, the influence of processing on elementary fiber tensile properties is shown to be limited. Then the preforms are evaluated in polypropylene matrix composites and mechanical properties are determined. The structure of non-woven reinforcements is strongly dependent on the manufacturing route. By varying the fiber content it is shown that the most efficient reinforcement for flax fibers is the mat produced by paper processing. The new spunlaced reinforced composites are shown to have...
Tipo: Text Palavras-chave: Flax fibers; Non-wovens; Composite materials; Polypropylene.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00307/41798/41241.pdf
Imagem não selecionada

Imprime registro no formato completo
Exploring durability of interfaces in flax fibre/epoxy micro-composites ArchiMer
Le Duigou, Antoine; Davies, Peter; Baley, Christophe.
The influence of wet aging on the behaviour of flax/epoxy micro-composites composed of single flax fibres embedded in epoxy micro-droplets has been studied. Interfacial shear strength has been examined by debonding the micro-droplets. The apparent interfacial shear strength decreases with immersion time in water, dropping rapidly during the first 15 min of immersion then stabilizing. Drying samples after short immersion periods allows recovery of properties, indicating a plasticization mechanism. For longer immersion times irreversible degradation is observed. Scanning electron microscopy reveals fibre surface peeling, indicating that an internal interface within the fibre is weaker than the fibre/matrix interface after aging. A simple descriptive model...
Tipo: Text Palavras-chave: Flax fibres; Environmental degradation; Fibre/matrix bond.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00137/24829/23101.pdf
Imagem não selecionada

Imprime registro no formato completo
Flax/PP manufacture by automated fibre placement (AFP) ArchiMer
Baley, Christophe; Kervoelen, Antoine; Lan, Marine; Cartie, Denis; Le Duigou, Antoine; Bourmaud, Alain; Davies, Peter.
Automated fibre placement (AFP) has been used to manufacture flax/polypropylene biocomposites for the first time. This required preparation of tape with a calibrated width from impregnated fibre sheets. The unidirectional tapes showed polymer-rich zones on the surface. During manufacture the polypropylene (PP) is melted locally with a laser. A consolidation step in a hot press is then required to reduce void content. The flax fibres, composed of polysaccharides, have limited thermal resistance so optimization of the thermal cycle is necessary, but subsequent characterization of mechanical behaviour showed no evidence of property loss in spite of an additional melting cycle. AFP appears to be a promising manufacturing method for biocomposites.
Tipo: Text Palavras-chave: Structural composites; AFP; Biocomposites; Flax; PP.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00307/41800/41009.pdf
Imagem não selecionada

Imprime registro no formato completo
Hygroscopic expansion: A key point to describe natural fibre/polymer matrix interface bond strength ArchiMer
Le Duigou, Antoine; Merotte, Justin; Bourmaud, Alain; Davies, Peter; Belhouli, Karim; Baley, Christophe.
The present article aims to investigate the contribution of hygroscopic expansion of flax fibres to interfacial radial stresses and Interfacial Shear Strength (IFSS) of Maleic Anhydride grafted PolyPropylene (MAPP)/Flax biocomposites. During manufacturing of thermoplastic biocomposites and storage at 50% RH, a weight variation is observed, attributed to water content evolution within plant cell-walls. The hygroscopic radial expansion coefficient βr flax of single flax fibres estimated by Environmental Scanning Electron Microscopy (ESEM) observation is many orders of magnitude higher (βf,R = 1.14 ε/Δm) than thermal expansion (αf, R = 78 10−6 ε/°C). Thus, its contribution to the development of residual stresses σrad during processing should be prevalent. A...
Tipo: Text Palavras-chave: Flax fibres; Fibre/matrix bond.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00397/50830/51594.pdf
Imagem não selecionada

Imprime registro no formato completo
Influence of embedded gap and overlap fiber placement defects on the microstructure and shear and compression properties of carbon-epoxy laminates ArchiMer
Lan, Marine; Cartie, Denis; Davies, Peter; Baley, Christophe.
This paper presents results from an experimental study of the influence of embedded defects created during automated fiber tape placement, on the mechanical properties of carbon/epoxy composites. Two stacking sequences have been examined, [(-45°/+45°)3/-45°] and [90°4/0°3/90°4], in which gaps and overlaps have been introduced during fiber placement. These materials have been cured in an autoclave either with or without a caul plate, then analyzed by ultrasonic C-scan. The microstructures were characterized by scanning electron microscopy. In-plane shear tests were performed on the ±45° laminates and showed that the use of a caul plate does not affect mechanical behavior of plies in the embedded defect region. Compression tests were performed on 0/90°...
Tipo: Text Palavras-chave: Structural composites; Defects; Mechanical properties; Mechanical testing.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00302/41337/40523.pdf
Imagem não selecionada

Imprime registro no formato completo
Influence of the degree of retting of flax fibers on the tensile properties of single fibers and short fiber/polypropylene composites ArchiMer
Martin, Nicolas; Mouret, Nicolas; Davies, Peter; Baley, Christophe.
The flax quality required for composite applications is not yet well established. Retting is one of the steps that are not well defined for these applications, and is a critical parameter during flax production. In this study, the influence of the degree of retting of flax on the properties of short flax fiber/polypropylene composites has been assessed. First, the degree of retting of gradually retted flax was measured by both qualitative and quantitative experimental techniques. In addition, water sorption studies were performed. Furthermore, tensile tests were carried out on both single fiber and injected composite materials. The microstructure of the composites was analyzed by scanning electron microscopy and X-ray microtomography. Single fiber and...
Tipo: Text Palavras-chave: Flax fibers; Dew-retting; Composite materials; Polypropylene; Injection molding.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00160/27076/25475.pdf
Imagem não selecionada

Imprime registro no formato completo
Influence of Through-Thickness Pinning on Composite Shear Properties ArchiMer
Maurin, Romain; Baley, Christophe; Cartie, Denis D. R.; Davies, Peter.
This paper describes results from tests to examine the influence of through-thickness pinning on in-plane shear behaviour, measured by tensile loading of +/- 45A degrees specimens. Samples were produced by both aeronautical and marine manufacturing processes. As few previous studies have investigated pinning of marine composites these were also subjected to out-of-plane shear delamination tests. For both carbon/epoxy laminates the pins reduce the apparent in-plane shear modulus and strength. Pins modify the strain field measured by full-field image analysis, and slow damage development. A new damage mechanism, transverse pin cracking, was observed.
Tipo: Text Palavras-chave: Z-pinning; Shear; Mode II; Damage; Acoustic emission.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00113/22390/20186.pdf
Imagem não selecionada

Imprime registro no formato completo
Interfacial bonding of Flax fibre/Poly(L-lactide) bio-composites ArchiMer
Le Duigou, Antoine; Davies, Peter; Baley, Christophe.
The use of glass fibre reinforced polyester composites raises many health and safety and environmental questions. One alternative is the development of high performance bio-based bio-composites with low environmental impact. Improved understanding of interfacial properties is essential to optimise the mechanical properties and durability of these materials, but so far few data are available. The present work describes the interfacial characterization of Flax fibre/Poly(lactic) acid (PLLA) system at the micro-scale using the microbond test. Different thermal treatments have been carried out (cooling rate and annealing) in order to evaluate the influence of matrix and interfacial morphologies as well as residual stress on interfacial properties....
Tipo: Text Palavras-chave: Flax fibre; Biopolymer; Biocomposite; Interfacial properties; Microbond test.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00000/11161/7808.pdf
Imagem não selecionada

Imprime registro no formato completo
Long term immersion in natural seawater of Flax/PLA biocomposite ArchiMer
Le Duigou, Antoine; Bourmaud, Alain; Davies, Peter; Baley, Christophe.
Innovation in sailing yacht design must include current environmental concerns such as resource depletion and waste management. Indeed most of the materials used today are petro-based and cannot offer viable end of life treatment. Fully biodegradable natural fibre reinforced biopolymers are being increasingly studied as they offer high specific stiffness and low environmental footprint. However, their ageing mechanisms are still not well understood. The present article gives information on 2 years natural seawater aging effect on injection-molded Flax/PLA biocomposite. Biocomposites suffer from relatively high moisture absorption which is controlled by the vegetal fibres. Simple rules of mixtures allow the determination of weight gain for flax fibres which...
Tipo: Text Palavras-chave: Natural fibre composites; Seawater ageing; Damage mechanism.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00211/32191/30681.pdf
Imagem não selecionada

Imprime registro no formato completo
Mechanical properties of composites based on low styrene emission polyester resins for marine applications ArchiMer
Baley, Christophe; Perrot, Yves; Davies, Peter; Bourmaud, Alain; Grohens, Yves.
Glass fibre reinforced polyester composites are used extensively for hulls and decks of pleasure boats. Boat-builders must optimise manufacturing technology, not only with respect to mechanical properties but also limiting volatile organic compounds (VOC) emissions. One way to achieve this is through modified polyester resin formulations such as low styrene content, low styrene emission or combinations of these. The resin matrix selection procedure is based on design specification (mechanical behaviour) but also manufacturing requirements and cost considerations. For this application post-cure is rarely used so it is important to optimise curing conditions. In this study the influence of the curing cycle on mechanical properties was examined first for two...
Tipo: Text Palavras-chave: Mat; Unidirectional; Glass fibres; Styrene emission; Mechanical properties; Transverse tensile; Unsaturated polyester; Composite materials.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-2320.pdf
Imagem não selecionada

Imprime registro no formato completo
Microstructure and tensile properties of carbon-epoxy laminates produced by automated fibre placement: Influence of a caul plate on the effects of gap and overlap embedded defects ArchiMer
Lan, Marine; Cartie, Denis; Davies, Peter; Baley, Christophe.
Automated fibre placement (AFP) enables the trajectory of unidirectional composite tape to be optimized, but laying down complex shapes with this technology can result in the introduction of defects. The aim of this experimental study is to investigate the influence of gaps and overlaps on the microstructure and tensile properties of carbon-epoxy laminates. First, a comparison between a hand-layup and AFP layup, draped and cured under the same conditions, shows equivalent microstructures and tensile properties. This provides the reference values for the study. Then, gap and overlap embedded defects (more or less severe) are introduced during manufacturing, on two cross-ply layups [(0°/(90°)5/0°] and [(90°/0°)2/90°]. Autoclave cure without a caul plate...
Tipo: Text Palavras-chave: Carbon fibre; Defects; Mechanical properties; Automated fibre placement (AR).
Ano: 2015 URL: http://archimer.ifremer.fr/doc/00275/38609/37138.pdf
Imagem não selecionada

Imprime registro no formato completo
Recommended flax fibre density values for composite property predictions ArchiMer
Le Gall, Maelenn; Davies, Peter; Martin, Nicolas; Baley, Christophe.
Density is one of the fundamental properties of fibres which reinforce polymer matrix composites, and is used both to estimate composite weight and to evaluate fibre content for property predictions. For traditional composites, reinforced by glass or carbon fibres, unique density values are well known for a particular fibre grade and provide reliable fibre content estimations and composite property predictions. However, this is not the case for natural fibres. This paper first reviews published density values for flax (Linum usitatissimum L.) fibres and describes the limitations of techniques used to measure fibre density. Significant variations in published densities are found, which can be related to the measurement method. New data quantify the...
Tipo: Text Palavras-chave: Density; Flax; Archimedes; Pycnometer; Volume fraction; Tensile modulus.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00427/53875/55082.pdf
Imagem não selecionada

Imprime registro no formato completo
Seawater ageing of low styrene emission resins for marine composites: Mechanical behaviour and nano-indentation studies ArchiMer
Maurin, Romain; Perrot, Yves; Bourmaud, Alain; Davies, Peter; Baley, Christophe.
Polyester resins are widely employed for pleasure boat construction. In order to satisfy new environmental legislation on styrene emissions resin suppliers have proposed modified formulations, but these show lower failure strains under tensile loading. This paper examines the influence of wet ageing on mechanical properties of low styrene polyester, together with standard polyester and vinyl ester resins, and their glass reinforced composites. Results are presented from accelerated ageing in natural sea water for nine months, at temperatures of 20, 40 and 60 degrees C. Nano-indentation was used to study local changes in the resin after ageing. The diffusion kinetics of the low styrene emission resins and their composites are similar to those for standard...
Tipo: Text Palavras-chave: Polymer matrix composites (PMCs); Environmental degradation; Mechanical testing.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/00000/11104/7856.pdf
Imagem não selecionada

Imprime registro no formato completo
Specific features of flax fibres used to manufacture composite materials ArchiMer
Baley, Christophe; Gomina, Moussa; Breard, Joel; Bourmaud, Alain; Drapier, Sylvain; Ferreira, Manuela; Le Duigou, Antoine; Liotier, Pierre Jacques; Ouagne, Pierre; Soulat, Damien; Davies, Peter.
The use of composite materials reinforced by flax fibres has been increasing steadily over the last 20 years. These fibres show attractive mechanical properties but also some particularities (naturally limited length, presence of a lumen, fibres grouped in bundles in the plant, complex surface properties and composition). An analysis of the available literature indicates that the quality of the composite materials studied is not always optimal (high porosity, incomplete impregnation, heterogeneous microstructure, variable fibre orientation). This paper reviews published data on the specific nature of flax fibres with respect to manufacturing of biocomposites (defined here as polymers reinforced by natural fibres). All the important steps in the process...
Tipo: Text Palavras-chave: Composite materials; Biocomposite; Flax fibre; Polymer; Processing.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00473/58429/61027.pdf
Registros recuperados: 17
Primeira ... 1 ... Última
 

Empresa Brasileira de Pesquisa Agropecuária - Embrapa
Todos os direitos reservados, conforme Lei n° 9.610
Política de Privacidade
Área restrita

Embrapa
Parque Estação Biológica - PqEB s/n°
Brasília, DF - Brasil - CEP 70770-901
Fone: (61) 3448-4433 - Fax: (61) 3448-4890 / 3448-4891 SAC: https://www.embrapa.br/fale-conosco

Valid HTML 4.01 Transitional