Abstract:

A series of ternary antioxidant composite systems based on Irganox^?1010 and 1076 as main antioxidants， Irgafos^?168 as an auxiliary antioxidant， and Revonox^?501 as a carbon radical capture agent. These antioxidant composite systems were applied for the modification of coal?based homopolypropylene （homo?PP） to enhance its thermo?oxidative aging performance. The resultant modified homo?PP samples were evaluated using polarizing optical microscopy， DSC， TGA， SEM and oxidation induction time， and their lifespan was predicted using the parameters obtained from TGA thermal analysis. The results indicated that the ternary antioxidant composite system had a much better enhancement effect on the thermo?oxidative aging performance of the coal?based homo?PP than the binary one， thus resulting in a much grea?ter OIT value. The incorporation of antioxidant composite system slightly enhanced the crystallinity of the coal?based homo?PP because the scission of PP molecular chains could be effectively prevented during the melting process. A synergistic effect derived from the ternary antioxidant composite system could improve the thermal stability of the coal?based homo?PP and prolong its lifespan at various ambient temperatures. A lifespan prediction demonstrated that the coal?based homo?PP modified with an optimal formulation of antioxidant composite system achieved a lifetime of 4.55×10⁵ h at an ambient temperature of 50 ℃.

Key words: coal?based homopolypropylene, ternary composite antioxidant system, thermo?oxidative stability, synerg?istic effect, lifespan prediction