Sustainable and efficient flame retardant materials for achieving high fire safety for polystyrene composites

Novel porous carbon sheets were developed as green, renewable, cost-effective, and efficient flame retardant material for thermoplastic polymers. Renewable porous graphite sheets were directly obtained from one pot recycling process of agriculture bio-waste sugar beet leaves at low temperature and used as scalable and efficient flame retardant for polystyrene. Thus providing dual benefits to environment for recycling of harmful bio-waste and developing new scalable and efficient flame retardant. The developed renewable flame retardant has specific surface area of 214 m2 g−1 and average pore size of 2.1 nm in addition to natural doping of precious metal residues. The sustainable porous graphite sheets were dispersed well in polymer matrix and their mass loading was altered and optimized giving rise to different polymer composites. Furthermore, different mass loadings of magnesium hydroxide were incorporated with porous graphite sheets in polymer composite. The thermal stability and flammability measurements of developed polymer composites elucidated the significant improvement in fire safety and flame retardancy of developed polystyrene composites. Thus, the reduction in peak heat release rate (PHRR) and total heat release rate (THR) of polymer composites were found to be 62 and 48%, respectively. This is in addition to a significant reduction in rate of burning and improvement in limiting oxygen index (LOI) value achieving reduction and improvement by 84 and 33%, respectively. Additionally, excellent suppression of emission of CO2 and CO gases was recorded (~ 40%). The outstanding flame retardancy and toxic gases suppression effect of developed porous graphite sheets was attributed to its charring capability and porous structure effect in conjunction to natural doping of desirable elemental composition. This study presents a new tool for production of scalable, green, renewable, and cost-effective flame retardant and smoke suppressant materials for thermoplastic polymers.