Melt blending was used to prepare a series of flame-retardant hybrids based on bisphenol A, polycarbonate (PC), potassium-4-(phenylsulfonyl)benzenesulfonate (KSS), and the organic silicon compounds N-(beta-aminoethyl)-gamma-aminopropylmethyldimethoxysilane (KH-602) and diphenylsilanediol. The flame retardancy and thermal stability of the hybrids were investigated by the limiting oxygen index (LOI) test, the UL-94 vertical burning test, and thermogravimetric analysis. The results show that the flame retardancy of the PC/KSS system and the weight of the residues improved with the addition of the organic silicon. When the content of diphenylsilanediol was 4 wt % and KH-602 was 1 wt %, the LOI value of the PC/KSS system was found to be 47, and Class V-0 of the UL-94 test was achieved. The microstructures observed by scanning electron microscopy indicated that the surface of the char for PC/KSS systems with KH-602 and diphenylsilanediol hold a more cohesive and denser char structure when compared with the pure PC/KSS system. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013