Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne

Saint-Sauveur-en-Rue, France

Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne

Saint-Sauveur-en-Rue, France
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Davies P.,French Research Institute for Exploitation of the Sea | Bourmaud A.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Pajot A.,British Petroleum | Baley C.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne
Industrial Crops and Products | Year: 2011

This short communication describes results from a preliminary characterization of the dimensions and mechanical properties of matricaria maritimum fibres. The aim is to develop a complementary industrial application of these plants, which are grown along the coast mainly for pharmaceutical use. The fibres are shown to be of small diameter, 5-10 μm, and tubular in form. Nano-indentation on fibres and tensile tests on fibre bundles provide an indication of the mechanical behaviour of these fibres, which are similar to those of sisal (leaf fibre) and miscanthus (grass fibre), and may be interesting for reinforcement of polymer matrix composites. © 2011 Elsevier B.V.


Baley C.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Le Duigou A.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Bourmaud A.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Davies P.,French Research Institute for Exploitation of the Sea
Composites Part A: Applied Science and Manufacturing | Year: 2012

The microstructure of flax fibres can be considered as a laminate with layers reinforced by cellulose fibrils. During a single fibre tensile test the S2 layer is subjected to shear. At room temperature, natural fibres contain water absorbed in the cell-walls. This paper examines the influence of this water at two scales: on the tensile behaviour of the flax fibres and on unidirectional plies of flax reinforced epoxy. Drying (24 h at 105 °C) is shown to reduce both failure stress and failure strain significantly. Analysis of normal stresses at the accomodation threshold provides an estimation of the shear strength of secondary cell walls as 45 MPa for fibres containing 6.4% by weight of water and only 9 MPa for dried fibres. Results from tensile tests on unidirectional flax/epoxy composites, reinforced by as-received and dried fibres, confirm the influence of drying on strength properties. © 2012 Elsevier Ltd. All rights reserved.


Le Duigou A.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Deux J.M.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Davies P.,French Research Institute for Exploitation of the Sea | Baley C.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne
International Journal of Polymer Science | Year: 2011

Biocomposites are sensitive to water, and previous work on flax reinforced PLLA showed a large drop in mechanical properties after immersion (Le Duigou et al. 2009). Unreinforced PLLA was much less sensitive. This paper presents a strategy to reduce the influence of wet ageing by adding extra layers of PLLA on the biocomposite surface. Weight gain measurements show that a PLLA coating 350 μm thick reduces weight gain by half, and biocomposite stiffness and strength after ageing are improved by 100% compared to uncoated composite behaviour. Thermal analysis and microscopic examination are used to show damage mechanisms with and without protection. Property changes are shown to be quasilinearly related to weight gain. Copyright © 2011 A. Le Duigou et al.


Le Duigou A.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne | Davies P.,French Research Institute for Exploitation of the Sea | Baley C.,Limatb Laboratoire Dingenierie Des Materiaux Of Bretagne
Composites Part A: Applied Science and Manufacturing | Year: 2013

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 has been used to identify diffusion kinetics, with a critical diffusion time corresponding to a change in degradation mechanism.© 2013 Elsevier Ltd. All rights reserved.

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