Synergistic effect of organic silicon on the flame retardancy and thermal properties of polycarbonate/potassium‐4‐(phenylsulfonyl) benzenesulfonate systems

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‐(β‐aminoethyl)‐γ‐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. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013