Processable Dispersions of Graphitic Carbon Nitride Based Nanohybrids and Application in Polymer Nanocomposites

Graphitic carbon nitride (g-C₃N₄) nanosheets are endowed with extraordinary chemical and thermal stability and good optical and photoelectrochemical properties and are expected to be used in a wide range of fields. The direct dispersion of hydrophobic g-C₃N₄ nanosheets in water or organic solvents without the assistance of dispersing agents is considered to be a great challenge. Here we report novel g-C₃N₄/organic-modified montmorillonite (OMMT) nanohybrids, which were synthesized through electrostatic interaction and then introduced into polystyrene (PS) matrix to fabricate nanocomposites by a simple solvent blending-precipitation method. Hybridizing g-C₃N₄ with OMMT could easily form stable aqueous colloids through electrostatic stabilization. These nanohybrids were evenly dispersed in PS and showed strong interfacial interactions with the polymer matrix. It is noted that the generation of total gaseous products was dramatically inhibited by combining g-C₃N₄ with OMMT. Moreover, flame retardancy was improved upon incorporation of the nanohybrids into PS host. These improvements were due to the strong interactions at interface of ternary systems, synergism between g-C₃N₄ and OMMT, and physical barrier effect of the two components. This work provides a new pathway to manufacture well-dispersed polymeric materials with enhanced fire safety.