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

Abstract

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.