Innovative lactic acid biopolymer / wood based composite material elaboration

Noël, Marion (2007). Innovative lactic acid biopolymer / wood based composite material elaboration (Dissertation, Université Henri Poincaré - Nancy I)

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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.

Item Type:	Doctoral Thesis (Dissertation)
Division/Institute:	School of Architecture, Wood and Civil Engineering School of Architecture, Wood and Civil Engineering > Institute for Materials and Wood Technology BFH Centres and strategic thematic fields > BFH Centre for Wood - Resource and Material
Name:	Noël, Marion
Subjects:	Q Science > Q Science (General) T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General)
Submitter:	Sally Haddad
Date Deposited:	22 Apr 2020 14:04
Last Modified:	16 Feb 2022 12:05
Related URLs:	Author
Uncontrolled Keywords:	lactic acid wood bio-polymer grafting softening darkening dimensional stability hardness middle lamella moulding coloration greffage ramollissement composite acide lactique PLA bois bio-polymère imprégnation stabilité dimensionnelle dureté lamelle mitoyenne densification mise en forme
ARBOR DOI:	10.24451/arbor.11446
URI:	https://arbor.bfh.ch/id/eprint/11446