Cette thèse a été réalisée au sein du LERMAB et du CETELOR et se consacre à la mise au point de matériaux composites biosourcés à plus de 98%. Des fibres libériennes de type lin, chanvre, kénaf et jute ont ainsi été sélectionnées, caractérisées chimiquement et physiquement. Les renforts en nontissés sont définis ici comme une superposition de voiles (ou nappes de fibres) cohésifs produits par cardage pneumatique et dont la consolidation est réalisée par aiguilletage. Les voies que nous avons choisies au cours de ce travail nous ont permis d'appréhender et de mettre en évidence l'importance de la qualité des fibres sur les propriétés mécaniques et structurales des matériaux développés. Les renforts réalisés dans un premier temps dans une gamme de poids de 200 à 800 g/m² en simple, double ou triple épaisseurs ont ensuite été optimisés dans le but de préserver les propriétés mécaniques des fibres et de permettre une bonne accessibilité de la résine d'imprégnation. Pour limiter les facteurs de complications, les paramètres process ont été limités pour toutes les fibres et composites. Les fibres ont été mises en oeuvre seules ou en mélanges, et imprégnées de matrice à base de résine naturelle tannin de mimosa et d'hexamine (comme durcisseur) ou de résine synthétique de type époxy. Des biocomposites à taux de fibres en masse de plus de 50% et de densité entre 0,9 et 1,2 ont été obtenus. Les modules d'élasticité atteignent 6 GPa en flexion et en traction. Pour les contraintes, les moyennes atteignent 42 MPa et 75MPa respectivement en traction et en flexion / This thesis was carried out within the LERMAB and the CETELOR and about the development of more than 98% biobased composites materials. Bast fibre type flax, hemp, kenaf and jute were selected, characterized chemically and physically. Nonwovens reinforcements are defined here as a superposition of cohesive webs products by pneumatic carding and consolidation by needling. The process we have chosen during this work allowed us to understand and to highlight the importance of the quality of the fibers on the mechanical and structural properties of the materials developed. Reinforcements made initially in a weight range from 200 to 800 g/m² in single, double or triple thicknesses have then been optimized to preserve the mechanical properties of the fibers and allow good accessibility of the impregnating resin. To limit the factors of complications, the process parameters have been limited for all fibers and composites. Fibers have been used singly or in mixtures, and impregnated by a matrix of natural tannin from mimosa and hexamine (as a hardener) or by synthetic resin of epoxy. Biocomposites with a rate of fibre mass over 50%, and density between 0.9 and 1.2 were obtained. Elasticity Modulus reach 6 GPa flexural and tensile. For strenght, averages reach 42 MPa and 75MPa respectively in tensile and bending

Memento Mitten is a project about seeing human hair from the perspective of sustainability as a viable alternative material. The project also aims to question our reluctance in Western Europe to use it in projects and innovations. It explores the process of transforming hair from waste into a functional piece (a mitten) by using traditional handicraft (hand carding, hand spinning and nålbinding) as a change agent in order to alter our perception of hair. Relating anthropologist Mary Douglas’ theory on dirt to the Freudian definition of ‘Das Unheimliche’ (The Uncanny) the project further examines and dissects the emotional aspects of Uncanniness and the anxiety we perceive when in contact with disembodied hair.  Leaning on Douglas’ theory on dirt I developed a framework for action that could potentially have the transformative ability to, when applied to creative practices, recontextualize hair from uncanny waste into an emotionally safe material. Utilizing auto-ethnographic documentation, physical exploration and participatory elements (through design interventions), four phases were identified: rejection (identifying hair as waste), re-collection (collecting hair), dissolution (taking apart the hair through acts like hand carding) and assimilation (putting the hair into a new context). These phases, which I titled The Altered Phases of Dirt, showed that they had the potential to move our inner margins of comfort beyond Uncanniness through the physical engagement found in handicraft.

This article reports the successful manufacturing of hybrid yarns from virgin staple CF (40 or 60 mm) or recycled staple CF (rCF) by mixing with polyamide 6 (PA 6) fibers of defined length. The hybrid yarns are produced using an optimized process route of carding, drawing, and flyer machine. Furthermore, the influence of CF length, CF type (i.e. virgin or rCF), CF volume content, and twist of the yarn are also investigated regarding the tensile properties of unidirectionally laid (UD) thermoplastic composites. The results show that CF length, yarn twist, and CF content of composites play a big role on the tensile properties of thermoplastic composites. From the comparison of tensile strength of UD composites produced from 40 and 60mm virgin staple CF, it can be seen that the increase of yarn twist decreases the tensile strength. However, the effect of twist on the tensile properties of UD composites manufactured from 40mm virgin staple CF is insignificant. The tensile strength of UD thermoplastic composites manufactured from the hybrid yarn with 40 and 60mm virgin staple CF and rCF is found to be 771 ± 100, 838 ± β1, and 801 ± 53.4 MPa, respectively, in the case of 87 T/m containing 50 volume% CF.

The availability of a considerable amount of waste carbon fiber (CF) and the increased pressure to recycle/reuse materials at the end of their life cycle have put the utilization of recycled CF (rCF) under the spotlight. This article reports the successful manufacturing of hybrid yarns consisting of staple CF cut from virgin CF filament yarn and polyamide 6 fibers of defined lengths (40 and 60 mm). Carding and drawing are performed to prepare slivers with improved fiber orientation and mixing for the manufacturing of hybrid yarns. The slivers are then spun into hybrid yarns on a flyer machine. The investigations reveal the influence of fiber length and mixing ratio on the quality of the card web, slivers and on the strength of the hybrid yarns. The findings based on the results of this research work will help realize value-added products from rCF on an industrial scale in the near future.