Convenient blending of alginate fibers with polyamide fibers for flame-retardant non-woven fabrics

Blending has been applied to combine the advantages of individual fibers, but the flame retardancy of a blended fiber depends on the interaction of the components. In this work, polyamide (PA) fibers were blended with alginate fibers to obtain a blended non-woven fabric and the flame retardancy of the natural/synthetic blended fabric was highlighted. Inspiringly, the two fibers mixed uniformly by the easy-to-handle blending, and the blend's components did not affect each other's thermal decomposition. With the addition of 50 wt% alginate fibers, the blended fabrics achieved self-extinguishing without any melt dripping in the vertical flame test, because the melted PA was limited in the area of the charred alginate fibers in the shape of films and bladders; besides, they showed strong decreases in peak heat release rate (56%), total heat release (59%), and total smoke release (66%) compared with PA fibers in the cone calorimeter test. Alginate fibers exhibited both vapor- and condensed-phase flame-retardant activities in the blended system, which was further confirmed by thermogravimetric analysis and thermogravimetry/infrared spectrometry.