Jiachun Feng

Developing effective compatibilizers is essential for improving the performance of immiscible polymer blends and enabling the upcycling of mixed plastic waste. In this work, a dynamically modified polyolefin elastomer (POE) compatibilizer was prepared, and its compatibilization effect was evaluated in polyethylene (PE)/polystyrene (PS) blends. Through dynamic melt-mixing POE with 2 phr benzoyl peroxide (BPO) at 160 °C for 30 min, a modified POE compatibilizer (designated as POEBPO) with a grafting level of 2.9 benzoate groups per 1000 carbon atoms was successfully obtained. Upon incorporating 10 wt % POEBPO into a PE/PS blend (80/20, w/w), the dispersed-domain size was decreased from 4.08 ± 1.8 μm to 3.24 ± 0.9 μm, while the elongation at break and notched impact strength were significantly improved compared to those of the blend containing 10 wt % unmodified POE. Spectroscopic analyses revealed increased gauche conformations of PS chains in the presence of POEBPO, which, together with other characterization results, indicate the existence of enhanced intermolecular interactions, likely involving π–π interactions between the grafted benzoate groups and the aromatic rings of PS. Together with the intrinsic structural similarity between the POE backbone and the PE matrix, the long-chain branched architecture of POEBPO and the possible π–π interactions synergistically contribute to the enhanced compatibilization efficiency for PE/PS blends. These findings demonstrate that dynamic modification of POE offers a practical strategy for preparing efficient compatibilizers for immiscible polymer blends, thereby providing a viable route toward the upcycling of mixed plastic waste.

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.