Chapter 6: Green Synthesis of Inorganic Fire Retardants

Compared with organic fire retardants, inorganic fire retardant counterparts also show comparable fire retardancy efficiencies in polymers. Though their traditional syntheses normally do not involve the use of organic solvents, this chapter focuses on recent advances in the green synthesis of inorganic fire retardants. Typically, these green synthesis strategies include the synthesis of various (nanostructured) metal oxides, the carbonization of biomass into biochars, and the preparation of derivatives of nano-carbon materials (e.g., C₆₀, carbon nanotubes, and graphene oxides). In addition, there are two other non-traditional fire-retardant strategies for in situ formation of fire retardants during polymer degradation: (i) “catalytic carbonization” of polymer matrices themselves using metal catalysts and (ii) self-crosslinking charring flame-retardant polymers, in particular polyethylene terephthalate (PET) via a “physical–chemical dual-crosslinking” and a “high-temperature rearrangement self-crosslinking” strategy. In brief, this chapter summarizes the recent achievements in terms of green synthesis of promising green fire retardants and fire-retardant technologies in the last few years, which adds new insights into the modern synthesis of inorganic fire retardants for polymers.