Blending alginate fibers with polyester fibers for flame-retardant filling materials: Thermal decomposition behaviors and fire performance

Abstract Polyester fibers are often applied as filling materials; however, they are flammable and exhibit melt-dripping. In this work, to prepare fibers with high flame retardancy, inherently flame-retardant alginate fibers were blended with polyester fibers, without using any toxic chemicals. The blended fibers with 20 wt.% alginate fibers achieved quick self-extinguishing without any melt-dripping in the vertical flame test and a test according to Pennsylvania Stuffed Toy Regulations. During the cone calorimetry test, the blended materials with 50 wt.% alginate fibers showed a remarkable decrease in heat and smoke release, compared with the blend with 20 wt.% alginate fiber and polyester fibers. Moreover, the alginate fibers could decompose prematurely and then delay the weight loss of polyester components when the natural/synthetic blends were subjected to heating. Also, they exhibited flame-retardant activities both in the vapor phase by the fuel dilution of non-flammable gases and in the condensed phase by forming calcium-enriched residues that were incompatible with polyester melts. Given their ease of preparation and high flame retardancy, the blended fibers have the potential for applications as filling materials of children's toys, furniture, and clothing.