• Doineau, Estelle
• Liagre, F.
• Gallard, Benjamin
• Beigbeder, J.
• Dumarcay, S.
• Moigne, Nicolas Le
• Gerardin, Philippe
• Duborper, A.
• Corn, Stéphane
• Rivard, P.
• Rabatel, Julien
• Day, A.

Abstract

Current environmental concerns push towards more sustainable and local practices forbiomass production. In this regard, agroforestry has been highlighted by researchers and policiesas a highly efficient approach for carbon sequestration (between 1.5 and 4 t C/ha/year), and asustainable alternative to deforestation with many agricultural benefits: deeper rooting of trees insoil, enhanced biomass productivity, crop fertilization... Agroforestry implies regular branch cutsthat are processed into wood chips and mostly used as energy wood or soil mulching. Newhigher added-value chains could be considered such as reinforcements or specific molecules forbio-based materials and chemistry.Besides, since 90’s, Wood-Plastic Composites (WPCs) have experienced significantgrowth, particularly in building (decking & siding), and constitute the largest share of bio-basedcomposites developed at an industrial scale. Nevertheless, the quality of WPCs and variability intheir performance are major technological issues for their implementation in industrialapplications. This could be related to the difficulty in tracing the various origin of wood fillers aswell as the different processing steps, from wood drying and defibration process to compositemanufacturing, that are not well controlled. Indeed, numerous interdependent parameters governthe final properties of WPCs, such as biochemical composition, presence of metallic andchemical contaminants (binders, wood treatment residues, varnishes, etc.), (micro)structure,thermal stability, mechanical properties of wood fillers, and the control of theirmilling/granulometry and further processing into composite materials.In this context, the development of quality-controlled agroforestry wood fillers in terms ofgranulometry (size and shape factor), chemical composition and physical (microstructure,mechanical) properties is therefore strategic for their implementation in wood-based products.This work investigates and evidences the influence of wood species (poplar, oak, walnut,chestnut)) and filler size and shape on the microstructure and mechanical properties ofpolypropylene (PP) / wood composites manufactured by extrusion/injection moulded. Moreover,wood from three recovery platforms in Brittany (mix of several species) was also investigated toevaluate the potential of existing agroforestry feedstocks.

Topics

• impedance spectroscopy
• microstructure
• polymer
• Carbon
• extrusion
• composite
• chemical composition
• wood
• drying