Thermal and Morphological Effect of Low-Tenor Alkali Treatment on Flax and Hemp Fibre Scraps: A Parametric Study.
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| Title: | Thermal and Morphological Effect of Low-Tenor Alkali Treatment on Flax and Hemp Fibre Scraps: A Parametric Study. |
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| Authors: | Xhafa, Sonila1 (AUTHOR), Pietracci, Lorenzo1,2 (AUTHOR), Giacomantonio, Roberto1,3 (AUTHOR), Marchetti, Fabio1,4 (AUTHOR) vincenzo.castorani@gmail.com, Castorani, Vincenzo2,5 (AUTHOR), Antonini, Marco3,6 (AUTHOR), Gunnella, Roberto1,4 (AUTHOR), Mattiello, Sara2,5 (AUTHOR), Fragassa, Cristiano3,6 (AUTHOR), Santulli, Carlo4,5 (AUTHOR) carlo.santulli@unicam.it |
| Source: | Materials (1996-1944). Apr2026, Vol. 19 Issue 8, p1573. 23p. |
| Subjects: | Alkalinization, Sodium hydroxide, Surface roughness, Linen, Hemp, Thermal analysis, Composite materials |
| Abstract: | Highlights: What are the main findings? In a low-tenor NaOH treatment on hemp and flax scraps, the temperature of the solution appears to be the most significant factor in modifying fibre characteristics by removing loose and worn-out matter. The effect on fibre roughness of a higher temperature and immersion time is proven on hemp and less so on flax. Calorimetric values on flax indicate a possible modification to the fibre structure at around 250 °C, which might indicate an onset of degradation, which does not appear to be resolved by alkali treatment. What are the implications of the main findings? While treatment stiffens both fibres, its effect on the tensile strength of flax, despite the low tenors used, can be considered seriously damaging. It appears to be easier to recover hemp than flax scraps for potential use in composites, especially due to their lower proneness to preservation of micro-voids after treatment. The possible inclusion of fibre scraps in pellets for thermoplastic processing appears largely conditioned by their different surface characteristics and appears limitedly affected by treatment. 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. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Highlights: What are the main findings? In a low-tenor NaOH treatment on hemp and flax scraps, the temperature of the solution appears to be the most significant factor in modifying fibre characteristics by removing loose and worn-out matter. The effect on fibre roughness of a higher temperature and immersion time is proven on hemp and less so on flax. Calorimetric values on flax indicate a possible modification to the fibre structure at around 250 °C, which might indicate an onset of degradation, which does not appear to be resolved by alkali treatment. What are the implications of the main findings? While treatment stiffens both fibres, its effect on the tensile strength of flax, despite the low tenors used, can be considered seriously damaging. It appears to be easier to recover hemp than flax scraps for potential use in composites, especially due to their lower proneness to preservation of micro-voids after treatment. The possible inclusion of fibre scraps in pellets for thermoplastic processing appears largely conditioned by their different surface characteristics and appears limitedly affected by treatment. 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. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 19961944 |
| DOI: | 10.3390/ma19081573 |
