Mechanical Properties and Flame Retardancy of SEBS-based Composites Filled with Magnesium Hydroxide

The flame-retardancy and mechanical properties of styrene-ethylene/butylene-styrene block copolymer (SEBS) based composites, containing SEBS blended with a paraffinic hydrocarbon extender oil, copolymer polypropylene (PP), and magnesium hydroxide (MH) or silane coupling agent surface-treated magnesium hydroxide (m-MH) were investigated. A maleic anhydride-grafted SEBS (MA-SEBS) was used as a polymer modifier for some composites. As the amount of MH or m-MH increased, the flame-retardancy of composites improved, while the tensile strength and elongation at break decreased, and the melt property of the composites became worse as well. When the oil-filled SEBS (O-SEBS) was partially replaced by MA-SEBS, the tensile strength of the composites increased, and elongation at break decreased. Furthermore replacing O-SEBS with MA-SEBS and treating MH with silane coupling agent (simultaneously) improved the tensile strength of the composites by a large margin. The phase structure of the composites was characterised using scanning electron microscopy (SEM) and this revealed that the particle-matrix interfacial bonding was improved through the addition of MA-SEBS. The stability of the composites was investigated by thermogravimetric analysis (TGA).