Carbon nanotubes grafted by polyurethane chains with dopamine-mediation to enhance the mechanical and damping properties of polyurethane elastomer

A novel strategy of combining mussel inspired dopamine chemistry and polycondensation reactions to construct unique functionalized carbon nanotubes (CNTs) with polyurethane (PU) chains was demonstrated. The polydopamine (PDA) was firstly functionalized to the surface of carbon nanotubes, then polydopamine acted as a bridge and covalently reacted with polyurethane chains to form a network structure named CNTs-PDA-PU, which improved the ability of polyurethane chains grafted onto carbon nanotubes. The functionalized carbon nanotubes significantly enhanced the mechanical and damping properties of nanocomposites. It was found that the highest mechanical properties were achieved at 0.1% loading of CNTs-PDA-PU, leading to the tensile strength and elongation at break increased by 97% and 25%, respectively, compared with matrix. More interestingly, the functionalized carbon nanotubes could form multiple physical and chemical interface interactions with matrix, thus alter the microphase separation structure of nanocomposites. This novel carbon nanotubes functionalization and elastomer synthesis method can provide ideas for the application of nanocomposites.