Laponite/polyurethane nanocomposites were successfully prepared by following two steps:(1) solvent-exchange approach to efficiently exfoliate Laponite into N

N-dimethyl acetamide (DMAC) solvent; (2) under ultrasound insert Laponite into polyurethane macromolecules.The structure and properties of the resulting nanocomposites were characterized by transmission electron microscopy (TEM)

atomic force microscopy (AFM)

thermogravimeric analysis (TGA)

differential scanning calorimetry (DSC)

thermodynamic mechanical analysis (DMA) and tensile testing.The results of TEM and AFM indicated that the most of Laponite was fully exfoliated into individual layers and uniformly dispersed in the polyurethane matrix.The Laponite platelets preferentially reinforce the hard segments or micro-domains of polyurethane because of the similar characteristic dimensions of Laponite and hard micro-domains and the hydrogen bond interaction

which was also further confirmed by DMA and DSC.The tensile testing results showed that the incorporation of Laponite into PU gave rise to significant improvements in mechanical properties

including tensile modulus

tensile strength and ultimate elongation.The hierarchical order induced by the addition of discotic Laponite platelets creates a percolated network that significantly improves the stiffness and toughness of the nanocomposites without reducing their extensibility.