Fig. 2: Synthesis and mechanical characterization.

a Modular assembly-like synthesis of crosslinked PTUs, and chemical structures of the designed modules. Note: The darker background colors of the boxes for steric modules and flexibility regulation modules indicate larger steric hindrance, and greater ability of raising macromolecules’ flexibility, respectively. b Comparison of tensile properties of the crosslinked PTUs developed in this work with those of commodity plastics, elastomers and fibers. Note: ABS acrylonitrile butadiene styrene, CR chloroprene rubber, EVA ethylene vinyl acetate copolymer, LDPE low density polyethylene, NR natural rubber, PAN polyacrylonitrile fiber, PB polybutadiene, PC polycarbonate, PE polyethylene fiber, PMMA polymethylmethacrylate, POM polyformaldehyde, PP polypropylene, PS polystyrene, PVC polyvinyl chloride, SBR styrene butadiene rubber, SBS styrenic block copolymers, TPU thermoplastic polyurethane.