Study of Ethylene–Vinyl Acetate Copolymer/Magnesium Hydroxide Flame‐Retardant Composites With High Mechanical Properties

ABSTRACT To improve the flame‐retardancy of ethylene–vinyl acetate copolymer (EVM), magnesium hydroxide (MH) is often added to prepare composites. Generally, the addition of a large amount of magnesium hydroxide will reduce the mechanical properties of the composites. To simultaneously improve both mechanical and flame‐retardant properties, we modified MH with flame‐retardant chitosan (CS) to improve its compatibility and dispersion in EVM. Based on the property of CS to dissolve in acidic solutions and precipitate in alkaline solutions, we employed a coprecipitation method to prepare the MH@CS filler . We studied the effects of MH@CS on the flame retardancy and mechanical properties of EVM. The results show that MH@CS imparts better flame retardancy and mechanical properties to EVM. The tensile strength of EVM/MH@CS was 143% of that of EVM/MH, while the elongation at break was 110% of that for EVM/MH. Additionally, the peak heat release rate (PHRR), total smoke production (TSP), and generation of harmful gases were significantly reduced in EVM/MH@CS, and the char layer formed after combustion was denser. At a 40 wt% flame‐retardant content, the limiting oxygen index (LOI) of EVM/MH@CS reached 28.4%. This study presents a feasible method for the development of EVM‐based flame‐retardant materials with high mechanical performance.