Effect of Antioxidants on Thermo-Oxidative Stability and Aging of Bio-Based PA56T and Fast Characterization of Anti-Oxidation Performance

Bio-based polyamide 56T (PA56T) is a new type of bio-based polyamide regarded as a promising material for sustainable solutions. The stabilization of PA56T compounded with Irganox 1098, Doverphos S9228, or SH3368 was studied by using a rotational rheometer and a circulating air oven at 150 °C. The thermal-oxidative aging resulted in an increase of the yellow color index of the PA56T/GF composites, which due to the carbonyl group as a chromophore group, continuously formatted during the aging process. After 10 days of aging, the mechanical properties and dynamic mechanical properties increase due to the molecular cross-linking and annealing effects. When the aging time is beyond 20 days, the degradation of molecular chain segments dominates, and the mechanical properties of PA56T/GF deteriorate continuously. The addition of antioxidants only slowed this effect and did not change the process of thermal-oxidative aging, which destroys the molecular chain. The results from both methods are consistent after a series of characterizations by FTIR, XRD, and so on. In the case of samples without lubricant, the rotational rheometer has the benefit of being less time-consuming than the accelerated aging experiment.