Physical Aging of Sustainable Polyester Materials towards High-End Consumer Products

To counter poor impact toughness in especially PET, impact modification with ethylene-butyl acrylate-glycidyl methacrylate was employed.The effect of aging was investigated on impact modified PET to understand the influence, especially in relation to the LEGO function, resulting in a patent application.Incorporation of impact modifier up to 8 wt% did not show any significant effects on physical aging rate measured as enthalpy loss and yield strength increase.Furthermore, impact modification was found to increase stress relaxation and decrease initial stress level, but it did not hamper the effect of accelerated aging (reducing stress relaxation), enabling improved functional durability in LEGO bricks after thermal treatment.