Reinforcement of PLA With a Novel One‐Dimensional Magnesium‐Based Hybrid Filler: Achieving Superior Mechanical and Flame Retardant Properties

ABSTRACT Polylactic acid (PLA) exhibits excellent biocompatibility and degradability but suffers from brittleness, low toughness, and flammability. In this study, a novel one‐dimensional magnesium‐based inorganic/organic hybrid flame retardant filler was synthesized by grafting 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) onto magnesium sulfate (MOS) whiskers modified with vinyltrimethoxysilane (VTMS), which can be melt‐blended into PLA to enhance its flame retardancy and mechanical properties. This article uses x‐ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), x‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis‐derivative thermogravimetry (TG‐DTG), and mechanical analysis. The flame retardancy of PLA significantly improves with the increase of DOPO‐MOS/PLA filler content, and its combustion grade increases from FH‐3 to FH‐1, while the melt dripping decreases. Carbon layer analysis indicates that the flame retardant effect is attributed to condensation and gas‐phase suppression. At a lower addition level, specifically when the amount is 2 parts per hundred resin weight (phr), the optimal impact strength reaches 8.22 kJ/m 2 , and the optimal bending strength reaches 10.91 MPa. Furthermore, the whiskers increased the crystallinity of PLA, reaching a maximum relative crystallinity of 35.23%. This article provides a reference for exploring new organic/inorganic flame retardant additives.