Synthesis of a novel organic-inorganic hybrid mesoporous silica and its flame retardancy application in PC/ABS

In this paper, a novel hybrid organic-inorganic mesoporous silica was synthesized through co-condensation of vinyltriethoxysilane (VTES) and tetraethyl orthosilicate (TEOS) in the presence of poly(ethylene glycol)-B-poly(propylene glycol)-B-poly(ethylene glycol) (P123) surfactants, followed by DOPO modification via the reaction between vinyl groups and P-H bond in DOPO. The mesoscopic order and pore structure of the hybrid mesoporous silica was characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2 isothermal sorption. The effect of DOPO-grafted hybrid mesoporous silica (DM) and triphenyl phosphate (TPP) on the fire retardancy in polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) was examined by limiting oxygen index (LOI), UL-94 test, thermalgravity analysis (TGA) and cone calorimeter. Composite PC/ABS with loading of 2 wt% DM and 6 wt% TPP reached LOI value of 28% and V0 rating in UL-94 test. Present high residual weight in TGA and low heat release rate (HRR) in the cone calorimeter. It also indicated that DM is a synergistic agent with TPP, which improved the thermal stability and promoted the system giving dense char layer at high temperature.