Light diffusing and flame-retardant polycarbonate modified by highly efficient and multifunctional organosilica microspheres

Abstract

Polycarbonate (PC) is widely used as a matrix in light diffusing material due to its high transparency. To prepare a light diffusing material, PC is blended with microparticles to scatter the incoming light and create haze without suffering much detriment in light transmittance. It also becomes critical to endow light diffusing PC with concurrent flame retardancy to extend its advanced application. A highly efficient and multifunctional potassium sulfonate functionalized organosilica microspheres (OM-SO3K) were synthesized and employed to produce light diffusing and flame-retardant PC. When the addition of OM-SO3K was only 0.4 mass%, the transmittance and haze of the composite were 78.6% and 90.2%, respectively, while the limiting oxygen index was increased significantly to 37.5% and the V-0 rating of UL 94 test was attained. The flame-retardant mechanism was studied by the characterization of pyrolysis gas, TGA, cone calorimeter test and the analysis of charred residue.