In Situ Generating CaCO₃ Nanoparticles Reinforced Nonflammable Calcium Alginate Biocomposite Fiber

Petroleum-based synthetic flame-proof fiber releases toxic volatile organic compounds in thermal decomposition process and has other problems, like tickling feeling and high density. A natural polysaccharide, calcium alginate, is an intrinsic fire-resistant biodegradable material, but its limited mechanical performance prevents it from being a practical flame-retardant fabric. To address this problem, Na₂CO₃ was doped into alginate spinning solution to obtain in situ generating CaCO₃ nanoparticle-reinforced alginate fiber by microfluidic spinning technique. Comparative analysis illustrated that incorporation of 0.50% Na₂CO₃ into the fiber greatly improved its mechanical performance; meanwhile, in situ generated CaCO₃ nanoparticles also throttled oxygen and heat flow in burning, endowing the fiber with excellent flame retardancy. The prepared composite fiber released less heat, smoke, and toxic volatile organic compounds in burning, which reduced the fire hazard. The formed residue char and pyrolysis products functioned as the physical barrier and displayed a synergistic effect to inhibit oxygen and heat transmission and impede the further combustion. All of the results demonstrate that the obtained fiber exhibits a good mechanical and flame-retardant performance, making it an ideal candidate as a fire-protection textile.