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International Journal of Polymer Science
Volume 2011, Article ID 235805, 8 pages
http://dx.doi.org/10.1155/2011/235805
Research Article

Protection of Flax/PLLA Biocomposites from Seawater Ageing by External Layers of PLLA

1LIMATB Laboratoire d'Ingénierie des Matériaux de Bretagne, Equipe Polymères et Composites, rue de Saint Maudé BP 92116, 56321 Lorient Cedex, France
2IFREMER Centre de Brest, Materials and Structures Group, BP70, 29280 Plouzané, France

Received 14 March 2011; Revised 7 June 2011; Accepted 16 June 2011

Academic Editor: Vincent Verney

Copyright © 2011 A. Le Duigou et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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  𝜇 m 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.