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Registros recuperados: 10
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Impact of hydrolytic degradation on mechanical properties of PET - Towards an understanding of microplastics formation ArchiMer
Arhant, Mael; Le Gall, Maelenn; Le Gac, Pierre Yves; Davies, Peter.
Ocean pollution by microplastics, i.e. small pieces of plastic of less than 5 mm, is one of the major concerns for the future of our planet. Secondary microplastics formation is due to fragmentation of macroplastic waste. This fragmentation can be attributed to environmental loadings such as waves, winds and tides, coupled with a change in mechanical properties of polymers induced by UV and seawater ageing. This study aims to characterize and understand changes in the mechanical behaviour of Polyethylene Terephthalate (PET) induced by hydrolysis, especially for high degradation levels. Thin films (200 microns) of PET were aged in water at temperatures from 110 °C to 80 °C for up to 150 days. Embrittlement occurs with chain scission during hydrolysis when...
Tipo: Text Palavras-chave: Hydrolysis; Polyethylene terephthalate; Mechanical properties; Molar mass; Embrittlement; Microplastics.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00476/58794/61331.pdf
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Modelling the non Fickian water absorption in polyamide 6 ArchiMer
Arhant, Mael; Le Gac, Pierre-yves; Le Gall, Maelenn; Burtin, Christian; Briancon, Christophe; Davies, Peter.
This paper investigates the water absorption of polyamide 6. The high amount of absorbed water in the polymer and the large resulting decrease in the glass transition temperature (Tg) leads to a non Fickian water diffusion when samples are immersed, which is a significant difficulty when trying to model the water profile in thick specimens. The aim of this study is to be able to model this particular behaviour based on physical considerations. First, it is shown that the non Fickian water diffusion is caused by an increase in the diffusivity during water absorption. Two cases are then identified; one below Tg where the diffusivity is described using an Arrhenius law and one above Tg based on the free volume theory. Then, these two laws are implemented in a...
Tipo: Text Palavras-chave: Water absorption; Free volume; Polyamide 6; Sea water; Modelling.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00350/46158/45856.pdf
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Main criteria of sustainable natural fibre for efficient unidirectional biocomposites ArchiMer
Bourmaud, Alain; Mérotte, Justin; Siniscalco, David; Le Gall, Maelenn; Gager, Victor; Le Duigou, Antoine; Pierre, Floran; Behlouli, Karim; Arnould, Olivier; Beaugrand, Johnny; Baley, Christophe.
This paper investigates biochemical, morphological and mechanical properties of a large range of plant fibres explored with the same methods. Biochemical results clearly exhibit strong differences between gelatinous, i.e. flax and hemp, and xylan type, i.e. jute and kenaf, cell walls. These differences into parietal composition have an impact on cell wall stiffness, highlighted through nanoindentation and atomic force microscopy measurements, but also on fibre individualisation, due to variations into fibre bundles cohesion. In addition, the morphology and particularly the lumen size induces apparent density differences. Moreover, the influence of fibre morphology and properties is demonstrated on UD materials. Finally, longitudinal Young’s modulus of each...
Tipo: Text Palavras-chave: Natural fibers; Biocomposite; Microstructures; Mechanical properties.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00505/61621/65646.pdf
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Novel mechanical characterization method for deep sea buoyancy material under hydrostatic pressure ArchiMer
Le Gall, Maelenn; Choqueuse, Dominique; Le Gac, Pierre-yves; Davies, Peter; Perreux, Dominique.
Syntactic foams, used in submersibles and in pipelines for deep sea oil wells, must be resistant to the severe conditions of the deep sea environment. As these foams will be in service for at least 20 years, their qualification testing is crucial. However, their mechanical characterization under real conditions of use is a challenge. In deep sea, the main loading is hydrostatic compression, however there is no standard procedure for testing material under pure hydrostatic pressure. The aim of this paper is to present a new characterization technique based on buoyancy loss measurement under hydrostatic pressure. To validate the method, two different syntactic foams (one brittle and one ductile) have been tested. Their behaviours under hydrostatic pressure...
Tipo: Text Palavras-chave: Hydrostatic compression; Syntactic foam; Deep sea; Mechanical characterization.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00201/31191/29590.pdf
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Effect of sea water and humidity on the tensile and compressive properties of carbon-polyamide 6 laminates ArchiMer
Arhant, Mael; Le Gac, Pierre-yves; Le Gall, Maelenn; Burtin, Christian; Briancon, Christophe; Davies, Peter.
Thermoplastic matrix carbon fibre composites offer considerable potential for underwater applications. Various material options exist but there are questions concerning the tension/compressive behaviour and water sensitivity of the less expensive polymers (e.g. polyamides) for these applications. The aim of the current work is to model water diffusion and its effect on the mechanical properties of thick carbon fibre reinforced polyamide-6 composite cylinders immersed in sea water for deep sea applications. To provide the data for such a model, thin specimens (2 mm thick) have been aged under different humidity conditions and tested in tension and compression. As water enters the composite, a significant reduction in the laminate properties is observed. An...
Tipo: Text Palavras-chave: Thermoplastic; Carbon fibres; Environmental degradation; Mechanical testing.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00368/47937/47971.pdf
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Potential solution for marine litter ? Assessment of the degradability and ecotoxicity of biobased composites ArchiMer
Niu, Zhiyue; Catarino, Ana Isabel; Davies, Peter; Le Gall, Maelenn; Curto, Marco; Jiang, Chulin; Dotcheva, Mariana; Vancoillie, Gertjan; Dhakal, Hom; Vandegehuchte, Michiel; Everaert, Gert.
Tipo: Text
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00620/73194/72389.pdf
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Yield stress changes induced by water in polyamide 6: Characterization and modeling ArchiMer
Le Gac, Pierre-yves; Arhant, Mael; Le Gall, Maelenn; Davies, Peter.
This paper considers the effect of water content on mechanical properties of polyamide 6 when used in a humid environment. First an experimental section presents the tensile behavior of polyamide with different amounts of water, with and without a through-thickness water gradient. Water profiles are introduced by immersion in sea water at 25 °C. The effect of testing temperature is also investigated in order to consider the influence of macromolecular chain mobility on the mechanical behavior. Then, in a second section, modelling of yield stress is proposed based on physical considerations. This can be used for life time prediction of PA6 in humid environment when plasticization is the main degradation mechanism.
Tipo: Text Palavras-chave: Yield stress; Water; Polyamide; Plasticization; Prediction.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00371/48208/48321.pdf
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Influence of Sea Water Aging on the Mechanical Behaviour of Acrylic Matrix Composites ArchiMer
Davies, Peter; Le Gac, Pierre-yves; Le Gall, Maelenn.
A new matrix resin was recently introduced for composite materials, based on acrylic resin chemistry allowing standard room temperature infusion techniques to be used to produce recyclable thermoplastic composites. This is a significant advance, particularly for more environmentally-friendly production of large marine structures such as boats. However, for such applications it is essential to demonstrate that composites produced with these resins resist sea water exposure in service. This paper presents results from a wet aging study of unreinforced acrylic and glass and carbon fibre reinforced acrylic composites. It is shown that the acrylic matrix resin is very stable in seawater, showing lower property losses after seawater aging than those of a...
Tipo: Text Palavras-chave: Acrylic; Thermoplastic; Infusion; Seawater; Immersion.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00347/45815/45541.pdf
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Comportement Mécanique de Composites Renforcés de Lamelles de Bambou, Influence du Vieillissement dans l’Eau de Mer ArchiMer
Davies, Peter; Arhant, Mael; Le Gac, Pierre Yves; Le Gall, Maelenn; Kemlin, Guillaume.
There are more than a thousand species of bamboo and some of these contain large amounts of fibres with attractive properties. However, the extraction of the fibres without damaging them is difficult, requiring energy and special equipment. One solution is to use the bamboo in the form of thin strips taken from fibre-rich regions of the plant, as done by the Cobratex company in an innovative process. These contain the fibres but they are protected from damage and keep their alignment. This paper presents the results from a study of bamboo strips, alone and in an infused composite. The influence of seawater immersion is investigated. The composite weight gain is high, around 25 %, but most of the water is in the natural canals of the wood. The influence of...
Tipo: Text Palavras-chave: Bamboo; Density; Mechanical properties; Wet aging.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00593/70534/68681.pdf
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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
Registros recuperados: 10
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