Attapulgite Decorated With Amino‐ <scp>PSi</scp> ‐ <scp> NH ₂ </scp> Particles to Obtain Highly Flame‐Retardant and Mechanically Reinforced <scp>PLA</scp> Composites

ABSTRACT Modifying phosphorus‐based flame retardants to balance their flame‐retardant and mechanical properties has become an emerging research trend in the field of polylactic acid (PLA). In this study, an attapulgite‐based phosphorus‐nitrogen‐silicon hybrid flame retardant (ATP@PSi‐NH 2 ) was designed and synthesized by coating a phosphorus‐nitrogen‐silicon hybrid flame retardant (PSi‐NH 2 ) onto the surface of attapulgite (ATP) using the bridging agent KH560. The effects of ATP‐KH560, PSi‐NH 2 , and ATP@PSi‐NH 2 flame retardants on the thermal stability, flame retardancy, and mechanical properties of PLA composites were compared. The incorporation of ATP@PSi‐NH 2 significantly enhanced the balance between flame retardancy and mechanical performance of the PLA composites. The PLA composite containing 7.5 wt.% ATP@PSi‐NH 2 achieved a UL‐94V‐0 rating, with the limiting oxygen index (LOI) increasing to 27.6%. At the same phosphorus content, the total smoke production (TSP) and total smoke release (TSR) of PLA/10ATP@PSi‐NH 2 were reduced by 38.6% and 39.3%, respectively, compared to the PLA/5PSi‐NH 2 composite, demonstrating the smoke‐suppressing effect of ATP. Furthermore, due to the enhanced interfacial compatibility of ATP@PSi‐NH 2 within the PLA matrix and the nail‐pull effect of ATP, the PLA/ATP@PSi‐NH 2 composite exhibited superior mechanical properties. This study successfully combines the benefits of phosphorus‐based and nano‐flame retardants to improve the flame‐retardant performance of PLA, providing an effective approach for the development of multifunctional flame retardants.