Bio‐Inspired Layered Double Hydroxide Analogues: Preparation, Characterization, and Fire‐Safety Enhancement in Silicone Rubber

ABSTRACT

Silicone rubber (SR) is limited by its inherent flammability and heavy smoke generation. Inspired by natural hierarchical structures (e.g., nacre, bone) where organic–inorganic synergies create exceptional properties, this study developed a bio‐inspired organic–inorganic hybrid flame retardant, gum arabic‐modified zinc‐cobalt layered double hydroxide (GAZC), via a one‐step co‐precipitation method. Gum arabic (GA), a natural, renewable polysaccharide rich in hydroxyl and carboxyl groups, was selected to modify zinc‐cobalt layered double hydroxide (ZnCo‐LDH). GA's oxygen‐containing groups enable electrostatic binding and hydrogen bonding with LDH layers, while its polysaccharide backbone serves as an excellent carbon precursor for char formation. With 5 wt% GAZC, the SR composite achieved a limiting oxygen index of 24.6% and a UL‐94 V‐0 rating. Cone calorimetry showed that the peak heat release rate and total smoke production decreased by 16.6% and 41.7%, respectively, compared with neat SR. GAZC also enhanced the thermal stability of SR composites. Residue and thermal degradation analyses indicated that GAZC promotes the formation of a continuous, dense silicon‐carbon char layer during combustion. This work presents a novel strategy for improving the flame retardancy, smoke suppression, and thermal stability of SR, offering valuable insights for designing safer silicone materials.