The exploitation in new materials of even the smallest scraps of textiles would contribute to their success in fields, such as the automotive industry. In this work, alkaline treatment with low tenors of sodium hydroxide (NaOH) was applied on flax and hemp fabric textile residues, trying to recover the most suitable process conditions as the function of the quality of treated fibres. Several parameters have been considered, the temperature and the concentration of the alkaline solution, the immersion time in it, and finally the immersion time in distilled water during the neutralization phase. Drying tests were carried out at a controlled temperature to verify the effects of the various treatment parameters. The effect of the various procedures was elucidated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) so to measure crystallinity, atomic force microscopy (AFM) to elucidate the variation of roughness, and nitrogen absorption/desorption cycles to how microporosities develop with treatment. It is suggested that only the 1.5 wt./vol.% treatment did produce some worthwhile modification of the fibres to prepare them for their use in composites, more evidently in flax than in hemp, though care needs to be taken about fibre embrittlement and potential permeability to water.

The exploitation into new materials of even the smallest scraps of textiles would contribute to their possible success in sectors such as the automotive industry. In this work, alkaline treatment with low sodium hydroxide (NaOH) concentrations was applied to flax and hemp textile residues, aiming to determine the most suitable process conditions as a function of the quality of the treated fibres. Several parameters were considered: the temperature and the concentration of the alkaline solution and the immersion time in the alkaline solution and, eventually, in distilled water during the neutralization phase. Drying tests were carried out under controlled temperature conditions to assess the effects of the various treatment parameters. The effects of the various procedures were elucidated by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) to assess crystallinity, atomic force microscopy (AFM) to characterize surface roughness, and nitrogen absorption/desorption cycles to determine how microporosity develops with treatment. It is suggested that only the 1.5 wt./vol.% treatment produced some worthwhile modifications of the fibres to prepare them for their use in composites, more evidently in flax than in hemp, though care needs to be taken about fibre embrittlement and potential water permeability.