A double-edged sword of ferrocene in polyurethanes against thermal-oxidative stress

Remedied during processing and service life, and then controlled ecologically, are ideal behaviors for polymers. Antioxidants and prooxidants always play their respective roles during the programming of their actions, and the oxygen-containing groups are non-controllable during oxidative stress. This work demonstrates an eco-friendly remedial strategy for polyester-based thermoplastic polyurethanes (TPUs). Upon the thermal-oxidative stressing, Fe(III) ions were released from the 2,2-bisferrocenylpropane doped in TPUs, polyester chains underwent β-scission, and iron-catalyzed oxidation directed new end groups to carboxylates. Ferroxane was progressively constructed by interaction between Fex3+Oy (2x > 3y) and external carboxylates. Consequently, the metallo-supramolecular networks were constructed to mitigate the mechanical degradation. Compared to virgin TPU, the sample containing only 1.0 wt% 2,2-bisferrocenylpropane, with 10-day thermal-oxidative stressing showed distinctly outperforming tensile strength (42.7 ± 1.9 MPa), breaking elongation (984 ± 61%), and Young's modulus (32.0 ± 1.6 MPa). The study would be interesting for preventing failure, lessening waste, and diminishing toxicity of the polymer, which is consistent with sustainable development.