Synthesis and characterization of CNT/thermoplastic polyurethane composites with a high-toughness

Carbon nanotubes (CNTs) were grafted with acrylic acid-3-(perfluoro-3-methykbutyl)-2-hydroxypropylate by an oxygen plasma-assisted method to increase their dispersion in thermoplastic polyurethane (TPU). The TPU monomers and the grafted CNTs were mixed and polymerized to prepare the CNT/TPU composites. Results show that the grafting procedure has little effect on the structure of the CNTs. The grafted CNTs have a fluorine content of 10.40% and a diameter of about 30 nm, and are uniformly dispersed in the TPU matrix. The tensile strength and elongation at fracture of the composites have maxima of 36.5 MPa and 630%, respectively, at a CNT content of 0.3%, and these are respectively 40.4% and 26.5% higher than those of pure TPU. Moreover, the surface free energy of the composites decreases from 27.3 to 9.9 mN/m with increasing CNT content from 0 to 0.8%.