Synergistic Effect of Natural Vitamin E and Antioxidant 1010 Combinations on the Stabilization of Polypropylene

ABSTRACT With increasing safety concerns of synthetic antioxidants, completely or partially substituting these compounds with natural ones is a potentially feasible approach. However, the stabilization effectiveness of natural antioxidants alone was usually limited. In this work, it was found that the combination of vitamin E (VE), a natural antioxidant, with the synthetic hindered phenol antioxidant 1010 significantly enhanced the thermal‐oxidative stability of polypropylene (PP). The samples with 0.2% VE and 1010 alone had an oxidation induction time (OIT) of 6.3 and 20.5 min, respectively, while samples with the same total addition amount (0.1% antioxidant 1010 and 0.1% VE) markedly prolonged the OIT to 55.5 min. The results of melt flow rate and yellowing index alterations following processing‐induced aging and carbonyl index changes after oven aging indicated that the combination of VE and antioxidant 1010 exhibited a pronounced synergistic effect. Mechanistic research suggested that the enhanced antioxidant effect was attributable to the synergistic regeneration of VE by antioxidant 1010. This mechanism was further demonstrated by the thermal‐oxidative stability of a combination of VE and another 2,6‐di‐ tert ‐butyl‐hindered phenol, antioxidant 1076. Our findings provided an important foundation for developing efficient and safe polymer products by reducing the use of synthetic antioxidants.