The thermal degradation of bisphenol A polycarbonate containing methylphenyl-silicone additive

The thermal degradation of the polycarbonate (PC)-silicone blend in N-2 was studied using thermogravimetry (TG), infrared (IR) and pyrolysisgas chromatography-mass spectrometry (PY-GC-MS). The major decomposition of PC-silicone blends occurred at 430-550 degrees C, which was similar to pure PC. The addition of silicone decreased the mass loss rate of PC in the major degradation step, and the mass loss rate decreased with the increase of silicone content. The degradation residues of the PC-silicone blends at 800 degrees C are higher than that of PC, and the solid residue shifted from 21% to 45% of the initial mass with the increase of silicone content. The phenyl silyl ether and the condensed aromatic compounds were detected in the solid residue of the PC-silicone blend by IR. These results indicated that the silicone could promote cross-linking reactions and char formation. The main volatile decomposition products of the examined blend were phenyl silyl ether derivatives containing Si-O-Ph bond except the common evolved components observed from PC and silicone. It was proposed that the phenyl sityl ether derivatives were produced by Si-O bond scission of polysiloxane from the chain ends to produce silyl radicals, which subsequently reacted with biphenol A or alkyl substituted phenol formed due to the decomposition of PC. (c) 2006 Elsevier B.V All rights reserved.