The thermal decomposition of two samples of glass filled Hetron 604 T-20 (brominated aliphatic polyester - Ashland Chemical) was examined by thermal gravimetric analysis (TGA). In the control sample (no Kemgard^®) the onset of thermal decomposition occurs at 311 C. By 470 C, the sample has lost approximately 65% of its weight.

The TGA for the Hetron sample containing 10% Kemgard^® 911C is markedly different. In this case the onset for thermal decomposition occurs at 290 C. This indicates that the Kemgard^® promotes char formation in the Hetron 604T-20 resin. As the temperature is increased, further thermal decomposition is retarded relative to the control. For example at 470C, the sample containing Kemgard^® has lost 36% of its weight compared to 65% for the control.

These results suggest that the char formed in the presence of Kemgard^® offers protection against further thermal decomposition. The protective char serves as a physical barrier for combustible material, retarding flame spread and lowering of smoke generation.