Use of lignocellulosic materials and 3D printing for the elaboration of conductive carbon strutures

Utilisation de matériaux lignocellulosiques et d'impression 3D pour élaborer des structures contuctrices

Ying Shao (1)

1 LGP2 - Laboratoire Génie des procédés papetiers

In the present work, electrically conductive and mechanically resistant carbon structures were elaborated by 3D printing and subsequent pyrolysis using microfibrillated cellulose/lignosulfonate/cellulose powder (labeled as MFC/LS/CP) blends. The processability of MFC/LS/CP slurries by 3D printing was examined by rheological tests in both steady flow and thixotropic modes. The printed MFC/LS/CP pastes were self-standing, provided a high printing definition and were proved to be morphologically stable to air drying and the subsequent pyrolysis. Pyrolysis at a slow rate (0.2°C/min) to a final temperature in the range of 400-1200°C was used to manufacture MFC/LS/CP carbons. The TGA/DTG was applied to monitor the thermal degradation of MFC/LS/CP materials in blends as well as in a separated form. The resulting carbons were further characterized in terms of morphology, microstructure and physical properties (such as density, electrical conductivity and mechanical strength). At 900°C, MFC/LS/CP carbons displayed a high electrical conductivity of 47.8 S/cm together with a low density of 0.74 g/cm3 as well as an important porosity of 0.58. They also achieved an elastic modulus maximum of 6.62 GPa. Such interesting electrical and mechanical properties would lead to a promising application of MFC/LS/CP- derived biocarbons in energy storage devices as electrode materials in close future.

Cette thèse a pour l’objectif d’élaborer, à partir de technologie additive 3D (extrusion de gel), des structures conductrices (électriquement) et résistantes (mécaniquement) en utilisant exclusivement des matériaux lignocellulosiques. Les matériaux sélectionnés sont des microfibrilles de cellulose (MFC), du lignosulfonate de sodium (LS ou NaLS) et de la cellulose en poudre (CP). Ces trois constituants peuvent être utilisés pour élaborer des hydrogels aqueux compatibles avec l’impression 3D (extrusion). De plus, ce procédé d’impression permet la mise en forme avec une excellente définition de structures à base de précurseurs de carbone dont les géométries peuvent être adaptées aux différentes techniques de caractérisation selectionnées.

Mots clés: Mfc/ls; Rheology; 3D printing; Pyrolysis; Kinetic analysis; Characterization of hard carbons

Mots clés: Mfc/ls; Rhéologie; Impression 3D; Pyrolyse; Analyse cinétique; Caractérisation de carbone dure

Domaines: Matériaux et structures en mécanique [physics.class-ph]

Ying Shao. Use of lignocellulosic materials and 3D printing for the elaboration of conductive carbon strutures. Materials and structures in mechanics [physics.class-ph]. Université Grenoble Alpes, 2017. English. ⟨NNT : 2017GREAI106⟩. ⟨tel-01737416⟩