Elaboration d'un matériau composite innovant à base de bois et de bio-polymère d'acide lactique

Abstract : Composites from petroleum based polymers and synthetical or mineral fibers can be advantageously replaced by biomaterials from biopolymers and vegetal fibrous reinforcements, allowing recycling and /or biodegradation at the end of their lifecycle. In this purpose, we prepared a wood / lactic acid biopolymer based bio composite. Wood vacuum / pressure impregnation by lactic acid oligomers containing chemical catalyst or not, was followed by a heating process in a drying kiln. The aim of this study was to induce oligomers polymerization into the wood cells, and a potential grafting on the free hydroxyls wood groups, in order to improve wood properties. We showed an effective in-situ polymerization, and a strong interaction between wood and biopolymers chains, however not grafted. The biopolymer impact on the lignocellulosic structure is shown by a significant softening of wood, occurring at an intermediate level of the heating process, probably due to a reaction between lactic acid oligomers and the lignin mainly contained into the middle lamella. The material darkening suggests a probable reaction between chemical catalysts and cellulose. Once the heating process has been completed, the composite gets stiff. The treatment imparts an excellent dimensional stability to the wood composite : an anti swelling efficiency approaching 70%. A good antifungal resistance is also noticed. As for mechanical properties, bending and compression resistances are slightly influenced, while hardness is significantly improved, and shearing resistance altered, due to the middle lamella degradation. Therefore, high density and hardness, plus a good material stability could be valorized by industrial uses such as flooring. In the intermediate state, moulding applications are also conceivable.
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http://docnum.univ-lorraine.fr/prive/SCD_T_2007_0061_NOEL.pdf
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Submitted on : Thursday, March 29, 2018 - 4:48:12 PM
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  • HAL Id : tel-01753753, version 1

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Marion Noël. Elaboration d'un matériau composite innovant à base de bois et de bio-polymère d'acide lactique. Autre. Université Henri Poincaré - Nancy 1, 2007. Français. ⟨NNT : 2007NAN10061⟩. ⟨tel-01753753⟩

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