Mechanical Reinforcement in Thermoplastic Polyurethane Nanocomposite Incorporated with Polydopamine Functionalized Graphene Nanoplatelet

Thermoplastic polyurethane (TPU) nanocomposites incorporated with polydopamine functionalized graphene nanoplatelet (PDA-GNP) were prepared by in situ polymerization. Fourier transform infrared spectroscopy results indicated that the addition of PDA-GNP could promote the formation of hydrogen bonding and microphase separation. The microstructure obtained from small-angle neutron scattering indicated that the addition of PDA-GNP increased the number while significantly it decreased the size of hard microdomains. Scanning electron microscopy demonstrated that PDA-GNP exhibited strong interfacial interactions with TPU matrix. In particular, the tensile strength, strain at break, and toughness of TPU/PDA-GNP with as low as 0.5 wt % PDA-GNP increased by 313, 16, and 279%, respectively. This individualized phenomenon was attributed to the abundant covalent bonding between PDA-GNP and TPU resulting in strong interfacial interactions and good compatibility specifically associated with the changes of TPU microstructure.