Tailoring the Biobased Polythiourethane Crosslinking Networks with Flame-Retardancy and Remote Ultrafast Infrared “Welding” Performance

Abstract

The common solution for developing thermosetting polymers with self-healing performance is to introduce covalent adaptive networks into the crosslinked systems. However, most of the self-healing polymers were conducted in “integral big materials”, which means “high energy consumption” and hard to carry out especially for those products with complex structure. In this work, the thermosetting polythiourethane (PTU) dynamic networks with remote ultrafast infrared “welding” performance were designed. At first, the biobased PTUs were synthesized by tailoring the crosslinking networks, which contains the dynamic thiocarbamate bonds. Then, MXene, used as photothermal stimulation, was incorporated into the crosslinked PTU networks. The tensile strength and modulus of the PTU ranged from 23.7 to 64.0 MPa and 17.4 MPa to 1.95 GPa, respectively, while the Tg can be tuned up to 83.4 ℃. Moreover, due to the excellent photothermal conversion behavior of MXene and reversibility of the dynamic thiocarbamate bonds, the PTU/MXene nanocomposites showed interesting remote and ultrafast infrared “welding” performance via the precise photothermal self-healing of the physical damage within 120s. Meanwhile, the crosslinked PTU showed excellent intrinsically flame-retardant properties. This study may provide a novel strategy to facilitate the self-healing process for the thermosetting polymers.