On the microstructure and physical properties of untreated raffia textilis fiber

We report on the first measurements of the physico-mechanical properties of the raffia textilis fiber. This fiber is the epidermis of the leaflet and is used to fabricate many ethnographical items. Scanning electron microscopy reveals a layered structure: a top layer with a tile-like structure, and a bottom layer with a honeycomb-like structure. X-ray diffraction and FTIR-ATR show the presence of cellulose I_β with a crystallinity index of 64%. Tensile tests give a Young’s modulus of 30 GPa, a tensile strength of 500 ± 97 MPa, and a total elongation between 2% and 4%. The fiber density is 0.75 ± 0.07, conferring to it the highest known specific mechanical properties among all studied raw vegetable fibers.