Bio-based coating for wool fabrics prepared from sodium alginate and Eobania Vermiculata  snail shell waste to improve flammability properties ​

This study investigates the development of a new sustainable bio-based coating to improve flammability properties of wool fabrics. The treatment contains a hybrid formula composed of Eobania Vermiculata (EV) snail shell microparticles rich in non-combustible calcium carbonate (CaCO ₃ ) and mineral content and sodium alginate (SA) used as a bio thickener. The direct coating method is used for the application. Vertical flammability tests demonstrated that coated fabric burning ceased before the ignition source was removed (12s). The char length decreased from 27.53 ± 4.27 cm in the untreated wool fabric (Wool-NT) to 5.4 ± 0.03 cm in the fabric treated with SA and EV snail shell microparticles (Wool-SA-EV). SEM images show a relatively smooth fiber surface due to SA thickener and distributed snail shell microparticles with different microparticle forms and sizes (< 90 µm). FTIR results confirmed, through the characteristic bands, the deposition of the treatment on the fabric surface through physical modifications. The increase in the tensile strength of Wool-SA-EV samples compared to the non-treated samples is of about (16.6%) with a significant increase in elastic strain and in elongation at maximum force (85.4%). Results highlight the feasibility of using an agrowaste to create an eco-friendly and bio-based coating for wool fabrics.