Biomimetic construction peanut-leaf structure on ammonium polyphosphate surface: Improving its compatibility with poly(lactic acid) and flame-retardant efficiency simultaneously

To suppress the fire hazards caused by polymer materials and at the same time keep or improve the properties of polymer materials, the exploration of high-efficiency flame retardants with property enhancement function is quite urgent. Inspired by the high adhesion result from the hierarchical micro-nanostructures of peanut leaves, herein, a bionic peanut-leaf structure is constructed on the surface of widely used flame retardant , ammonium polyphosphate (APP) to improve the compatibility with polymers. To test the validity of this modification method, poly(lactic acid) (PLA) with poor toughness and high fire risk is selected as a model polymer and blended with modified APP (MAPP). The high interfacial adhesion caused by the hierarchical micro-nanostructures of MAPP enhance the compatibility with PLA resulting in the toughness enhancement of materials. Owing to unique microstructure, 5 wt% addition of MAPP not only endow material with good flame retardancy but also enhance the elongation at break and notched Izod impact strength to 21 and 3 times of pure PLA. The biomimetic strategy outlined here can be extended to other flame retardant and may provide us a new method to balance the flame retardancy and mechanical properties.