Multi-scale morphological characterisation of flax: From the stem to the fibrils

In this study, investigations were carried out on flax at different levels of observation. Stems, bundles and elementary fibres were studied in order to correctly understand the fibre structure and deformation so that the mechanical behaviour of derived flax fibre-based composite materials could be modelled. New structural information was obtained and correlated to mechanical properties. The main results are that fibres taken near the root are the largest of the stem, that both intra-bundle size variability and inter-fibre size scattering are linked to large intra-fibre size dispersion, that fibre mechanical properties should be calculated on the basis of their diameter near their rupture point rather than their mean diameter, and that a new schema of the fibre internal structure could be drawn from focused ion beam experiments.