Abstract This study investigates the development of eco-friendly flame retardant wool/polyamide fabrics by applying calcium alginate coatings containing boron compounds (zinc borate, colemanite, ulexite and borax pentahydrate) at different concentrations (1%, 3% and 5%). The coating solution was prepared using sodium alginate as the film-forming matrix and applied to fabrics by a dip coating process. The coated samples were characterised through alambeta, permetest, air permeability, LOI, DSC, TGA, SEM, FTIR and tensile strength analyses. The results revealed that the alginate boron coatings enhanced the thermal stability, tensile strength and flame retardancy of fabrics, while slightly reducing air and water vapour permeability due to increased surface coverage and fabric thickness. SEM and FTIR analyses confirmed uniform coating formation and the successful integration of boron based functional groups on the fabrics surface. Thermal analyses (TGA and DSC) demonstrated increased char residue and glass transition temperature, particularly for ulexite and colemanite modified samples, confirming improved heat resistance. LOI values increased by up to 142% compared to untreated sample, classifying the coated fabrics as highly flame retardant materials. Mass, elemental (EDX) and thermal (TGA) analyses carried out after five wash cycles; whilst demonstrating that coatings containing colemanite and zinc borate are largely preserved on the fabric surface, have revealed that detergent residues, even those incorporated into the fibre structure during the washing process, lead to characteristic changes in the material’s thermal decomposition stages and elemental composition. Overall, the findings highlight that alginate-based coatings incorporating boron compounds offer a sustainable, halogen-free alternative for enhancing the functional performance of textile materials, making them suitable for protective and technical textiles.
Kilinc et al. (Mon,) studied this question.