Pyrolytic propensity of plastics mixture was estimated in terms of those of individual plastic components. General trends of pyrolysis of plastics mixture could be depicted by simple addition of those of individual components without considering any particular synergistic or inhibition effects. However, pyroly-sis temperatures of individual components in the blend were edtermined by the weights of components corresponding to the whole blend, not by the real weights of individual components in the blend. More important was the weight of the whole sample, rather than the weight of each component, in a sampling pan because all thermoplastics in the pan would melt and agglomerate when heated.