▎ 摘　　要

Graphene nanoplatelets (GNPs) with the char barrier effect were combined with brominated polystyrene (BPS) and antimony trioxide (Sb2O3) to improve the flame retardancy and thermal stability of high-density polyethylene. Thermogravimetric analysis, limited oxygen index (LOI) testing, and vertical burning testing (UL-94) showed that the presence of GNPs led to enhanced thermal oxidation stability and significantly reduced the flammability. The addition of 1 wt % GNPs to polyethylene/BPS-Sb (mass ratio=92/6/2) led to UL-94 grades from NG (first burning time>30 s) to V-2 (total burning time=14 s), and the LOI value increased from 23.4 to 24.1%. The results of the pyrolysis products provided evidence that the GNPs restricted volatilization. The morphology of the chars also proved the formation of the char layer, which could act as a barrier to isolate the material from the flame and retard the vaporization of flammable gases via a tortuous pathway. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40520.