Nanoporous carbon doped with metal oxide microsphere as renewable flame retardant for integrating high flame retardancy and antibacterial properties of thermoplastic polymer composites

Abstract

Innovative, renewable and cost-effective porous composites were developed for integrating high fire safety and antibacterial properties for thermoplastic polymers. Sustainable porous carbon sheets were developed from plum stones as fruits-by-products via single carbonization step affording dual environmental and economic benefits. The as-developed porous carbon own specific surface area of 165 m2 g−1 which is characteristic of mesoporous feature of an average mesopore size of 2.1 nm, in addition to naturally doped nitrogen species. The obtained porous carbons sheets were dispersed in different mass loadings in to polystyrene matrix-producing polymer composites. Interestingly, SnO2 microsphere of an average size of 2 µm was synthesized on the surface of developed porous carbon sheets producing new porous composites. The new composites were elucidated using XRD, FT-IR and SEM–EDS. Then, the developed composites were dispersed in polystyrene. The mass loadings were altered and studied. The progress in fire safety, thermal stability and antibacterial properties for developed polymer composites was studied. The flame retardancy of the new composites was significantly improved achieving rate of burning of 20.5 mm min−1 compared to 46.5 mm min−1 for blank polymer. This superior flame retardancy was corroborated by recording LOI value of 24.5% compared to 18% for virgin polymer. This attained flame retardancy was ascribed to the synergistic effect between porous carbon sheets contained nitrogen and SnO2 microsphere. The new composites afford promising inhibition for bacterial growth achieving clear antibacterial inhibition zone of 11 mm compared to zero for blank sample. The flame retardancy action was studied and elucidated.