Biopolymer-Based Flame Retardants and Flame-Retardant Materials

Polymeric materials featuring excellent flame retardancy are essential for applications requiring high levels of fire safety, while those based on biopolymers are highly favored due to their eco-friendly nature, sustainable characteristics, and abundant availability. This review first outlines the pyrolysis behaviors of biopolymers, with particular emphasis on naturally occurring ones derived from non-food sources such as cellulose, chitin/chitosan, alginate, and lignin. Then, the strategies for chemical modifications of biopolymers for flame-retardant purposes through covalent, ionic, and coordination bonds are presented and compared. The emphasis is placed on advanced methods for introducing biopolymer-based flame retardants into polymeric matrices and fabricating biopolymer-based flame-retardant materials. Finally, the challenges for sustaining the current momentum in the utilization of biopolymers for flame-retardant purposes are further discussed.