Effects of triphenyl phosphate on styrene suspension polymerization process and flame retardance properties of polystyrene/triphenyl phosphate nanocomposite

Preparation of polystyrene nanocomposites containing flame retardants is difficult to achieve in one step by suspension polymerization. Styrene suspension polymerization was studied to determine the effects of the flame retardant on the polymerization process and properties of polystyrene beads. Triphenyl phosphate (TPP) was used in this work, which can dissolve completely in styrene monomers. The results showed that TPP were nanosized spherical particles, distributed homogenously and uniformly in a polystyrene (PS) matrix, and the formation mechanism of TPP nanoparticles was also investigated. In addition, the effects of TPP on the styrene polymerization process were investigated. With TPP amount increasing, the polymerization time increased significantly; molecular weight of PS nanocomposites also decreased and molecular weight distribution became wide; the particle size distribution (PSD) of the PS nanocomposites became wider than pure PS slightly as the particle size decreased. PS/TPP nanocomposites obtained good flame retardance because of nanodispersed TPP particles in its matrix. In a word, the suspension polymerization method provides a facile approach to prepare PS/TPP nanocomposites with better properties.