Doped CNC-Na2CO3 reinforcing alginate bio-based fiber as fire-safety composite applied in the household textile

We adopted a straightforward yet efficient method to improve mechanical property of alginate fiber by doping cellulose nanocrystal and Na2CO3 in the spinning solution to fabricate CaCO3-cellulose nanocrystal reinforced alginate fiber. Comparative analysis demonstrated that this composite fiber containing 0.30% cellulose nanocrystal and 0.40% Na2CO3 achieved a maximum breaking strength of 1.42 ± 0.32 cN/dtex, three times more than the pristine alginate fiber. Doped Na2CO3 triggered in situ generating CaCO3 particle during formation of the fiber and deposited extra NaCl particle, which can endow the composite fiber with remarkable fire resistant performance. Also, the composite fiber released limited heat, smoke and toxic gaseous compounds, assisting to reduce fire hazard. Finally, the flame-retardant mechanism of fuel-dilution cooperating with a physical barrier of residue char was proposed. It has a synergistic effect with nonflammable emissions on the inhibition of inflammable emission, generated heat and incoming oxygen transmission, which impeded further combustion. The prepared composite fiber has robust mechanical performance and excellent fire-proofing ability, making it an ideal candidate as flame resistant household textile.