Tunable flammability studies of graphene quantum dots-based polystyrene nanocomposites using microscale combustion calorimeter

Polymer composites with improved thermal and flame-retardant performance are imperative for fire-safe materials. Carbon-based nanomaterials have the advantages of low cytotoxicity, chemical inertness, cost-effectiveness, and biocompatibility. Graphene quantum dots (GQDs) as a new member of carbon-based nanomaterials were fabricated by pyrolysis method, and easy to be functionalized to fabricate nanocomposites as efficient flame retardant. Herein, polystyrene (PS) nanocomposites with introduction of modified graphene quantum dots (C-GQDs) were fabricated by the Pickering emulsion polymerization method. The C-GQDs with controllable chemical structure could be used as stabilizer in emulsion polymerization system and introduced to PS directly. Morphological and chemical characterization of PS nanocomposites revealed that the successful introduction of C-GQDs to PS, and C-GQDs were wrapped on the surface of PS microspheres. The flammability behavior of the PS nanocomposites was investigated by using microscale combustion calorimeters (MCC), and the peak heat release rate of PS nanocomposite was reduced 40% when compared with that of neat PS. The improved flame retardancy was mainly attributed to the C-GQDs promoting the formation of physical protective barrier on the surface, which impeded the permeation of heat and the pyrolysis products. Therefore, a facile method for preparing nanocomposite has been developed in this work, and C-GQDs could be used as flame retardants to reduce the flammability of polystyrene nanocomposites system.

Automated summary

This study successfully fabricated polystyrene nanocomposites with improved thermal and flame-retardant performance. The nanocomposites utilized modified graphene quantum dots as flame retardants, which effectively reduced the flammability of polystyrene.