Simultaneous reinforcement and toughening of polyurethane composites with carbon nanotube/halloysite nanotube hybrids

In this work, three-dimensional (3D) hybrid nanofillers, composed of acid-treated multi-walled carbon nanotubes (a-CNTs) and silane-treated halloysite nanotubes (s-HNTs), have been successfully prepared through covalent bonding. By using simple solution-casting method, polyurethane (PU) elastomers reinforced with these s-HNT/a-CNT (HC) hybrid nanofillers have been fabricated. The morphology and mechanical properties of the resultant hybrid and PU composites are characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and tensile tests. Tensile test data show that the tensile strength, Young’s modulus and elongation at break of the resultant PU composite with merely 1 wt% HC hybrids are significantly improved by 140%, 35% and 68% respectively. This clearly demonstrates the synergistic reinforcement of one-dimensional CNTs and HNTs within the hybrid in improving the strength and toughness of PU composite. Therefore, the s-HNT/a-CNT hybrid thus prepared is an ideal agent for simultaneous reinforcement and toughening of PU elastomers.