Effects of Hindered Phenolic Antioxidants With Different Bridging Structures on Thermal and Oxygen Aging Behavior of Nylon 66

ABSTRACT Nylon 66 (PA66) is widely used, but it often faces aging issues in service. Antioxidants are commonly used to inhibit the aging of PA66 and extend its service life. However, hindered phenol antioxidants with low molecular weight have poor migration resistance and thermal stability, leading to difficulty in maintaining continuous and stable effectiveness during service. Here, a novel macromolecular hindered phenolic antioxidant with an ester bridging structure, 2‐((3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl)propanoyl)oxy)ethyl acrylate‐N‐phenylmaleimide copolymer (POE), was synthesized. The POE exhibits better free radical scavenging capacity than 3‐(3,5‐di‐tert‐butyl‐4‐hydroxyphenyl) propionic acid 2‐acrylamidoethyl‐N‐phenylmaleimide copolymer (PAN), which possesses an amide bridging structure. As a result, the tensile strength of PA66/POE remains at its original level (82.14 MPa), while the retention of impact strength is 65.4%, decreasing from 6.24 to 4.08 kJ/m 2 , following 12 days of thermal‐oxidative aging at 150°C. In contrast, the retention of tensile strength and impact strength of PA66/PAN was 48.6% (decreasing from 76.60 to 37.23 MPa) and 49.8% (decreasing from 6.15 to 3.06 kJ/m 2 ), respectively. In addition, POE and PAN have superior antimigration properties in PA66. This work serves as a reference for the development of macromolecular antioxidants.