25 - Polymer-graphene composites as flame and fire retardant materials

Abstract

Graphene, a 2-D carbon crystal structure with repeating resemblance of a honeycomb in a hexagonal lattice possesses the ability to work as a multifunctional additive to improve mechanical, electrical, and thermal properties. One of the key properties that opens up several areas of application for graphene use is flame retardancy. Out of many facets, this wonder material possesses the ability to impart flame retardancy to a polymer upon its incorporation in percentages as low as 5% with or without the action of a synergist by improving properties such as peak heat release rate and temperature, total heat release, total smoke produced, time to ignition, char residue mass%, Limiting Oxygen Index and UL-94 flame rating which determine the flame retardancy of the polymer. The effect of flame retardance is due to a physical barrier restricting heat and mass transfer from the inside and outside, thereby breaking the fire triangle to extinguish fire. However, the challenge is its dispersion in the polymer matrix for which there are chemical modifications carried out before its incorporation in the polymer. The effect of graphene in flame retardance is tested for a few polymers and the scope to test it for other polymers makes it interesting to learn about the methods and mechanism.