Organic-inorganic hybrid strategy based on ternary copolymerization to prepare flame retardant poly(methyl methacrylate) with high performance

Abstract

It is always a challenge to improve the flame retardancy of poly (methyl methacrylate) (PMMA) without uncompromised mechanical properties, transparency and other properties. In this research, an organic-inorganic hybrid strategy to prepare flame retardant PMMA with satisfying thermal stability, mechanical properties and transparency, is reported. A new reactive phosphorus containing monomer (MDP) is copolymerized with methyl methacrylate to provide flame retardant function, and meanwhile, octa-vinyl polyhedral oligomeric silsesquioxane (V-POSS) serves as a reinforcer, is chemically combined with the copolymer. The organic-inorganic hybrid copolymerized nanocomposite with 10 mol% MDP and 0.5 mol% V-POSS, shows significantly enhanced limiting oxygen index (LOI), decreased heat release rate compared with PMMA. The flame retardant mechanisms are analyzed and discussed in detail. Additionally, its initial decomposition temperature is increased by 42 °C, showing higher thermal stability. The terpolymer also exhibits greatly improved mechanical property due to the introduction of V-POSS, and its tensile strength, young's modulus and impact strength are much higher than those of MMA-MDP copolymer. Finally, it also keeps good optical property comparable to PMMA. As a result, Our research provides an effective way to prepare intrinsic flame retardant PMMA with good comprehensive performance.