Enhanced thermo-oxidative stability of a polybutylene succinate/polylactic acid/salix composite material via combined ternary antioxidant system

Although biodegradable polymers such as polylactic acid (PLA) and polybutylene succinate (PBS) represent promising sustainable alternatives to conventional plastics, their practical adoption in WPCs is critically limited by poor thermo-oxidative aging resistance. To date, effective strategies for bolstering thermo-oxidative stability in such composite systems have yet to be systematically investigated, and the combined use of multiple antioxidant mechanisms remains particularly unexplored. To fill this gap, we developed a PBS/PLA/salix composite incorporating a ternary antioxidant system comprising hindered phenolic antioxidant 1010, phosphite antioxidant 168, and hydroxylamine antioxidant 420 at a mass ratio of 2:2:1. When the total antioxidant dosage was 0.6 wt%, the respective retention rates of the elastic modulus and static bending, tensile, and impact strengths of the composite of 103.00%, 80.30%, 93.08%, and 82.72% were the highest after 128 h of thermo-oxidative aging. The color difference of 2.25 was the smallest. Compared to those of the composite without antioxidants, the elastic modulus and static bending, tensile, and impact strengths were increased by 11.44%, 10.28%, 10.55%, and 9.77%, respectively, and the color difference was reduced by 61.14%. The composite material exhibited the optimal resistance to thermo-oxidative aging. This study provides a novel approach to improving the anti-aging properties of biodegradable WPCs.