Ca2+ crosslinking sodium alginate/graphene oxide composite fiber with enhanced mechanical strength and fire retardancy

Abstract

It is crucial to enhance the mechanical properties to realize the application of sodium alginate (Alg) in engineering materials. Herein, a Ca2+ cross-linked sodium alginate/graphene oxide (CAlg/GO) composite fiber with a secondary reinforcement structure was prepared via wet spinning. The microstructure and physical properties of the fibers were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and mechanical strength testing. The composite fiber’s strength and toughness improved significantly, benefiting from the uniform distribution of GO in the Alg matrix together with the simultaneous cross-linking of Ca2+ to Alg and GO sheets. Accompanying the addition of GO reaching 15%, the strength increased by 184 ± 16%. Meanwhile, the CAlg/GO composite fiber possessed a significant improvement in flame retardancy; the limiting oxygen index increased from 33 to 37 after adding 10% GO sheets to the fiber. In addition, the composite fiber’s reinforcement, toughening, and flame retarding mechanisms were discussed from the point of the interaction between Alg, GO, and Ca2+, as this study will provide data and theoretical reference for the application of high-performance CAlg/GO composite fiber.