Sodium alginate-templated synthesis of g-C3N4/carbon spheres/Cu ternary nanohybrids for fire safety application.

Constructing novel graphic carbon nitride (g-C3N4)-based nanohybrids via a facile method for high-performance polymeric materials which exhibit enhanced fire safety properties are highly desirable. Here, the g-C3N4/carbon sphere/Cu (denoted as CSACS-C) nanohybrid was prepared by metal ions-induced gel reaction using sodium alginate as a green template, and thereafter introduced into thermoplastic polyurethane (TPU) matrix to prepare nanocomposites. Microstructure analyses indicated the successful synthesis of the ternary nanohybrid, where both the g-C3N4 nanosheets and Cu nanoparticles were well-dispersed in the carbon material. Moreover, the ternary nanohybrid showed good distribution in TPU matrices, and exhibited strong interfacial adhesion with the polymeric host. It is worth noting that addition of these nanohybrids led to significantly improved fire safety. Particularly, remarkably reduced pyrolysis gaseous products generation and peak of heat release rate were achieved for TPU/CSACS-C system. This enhanced fire safety was due to the interpretations that the SACS and g-C3N4 nanosheets retarded the heat and mass propagation, while the incorporation of Cu nanoparticles induced earlier thermal decomposition into more char residues and less pyrolysis gaseous products. The work provides a new, simple strategy to prepare nanohybrids for polymeric materials with enhanced fire safety.