Incorporation of functional nanofillers can unlock the potential of polymers as advanced materials. Herein, single-layered and three-dimensional reduced graphene oxide (rGO)/Ti3C2Tx (B-rGO@Ti3C2Tx) nanohybrids were constructed using bis(2-hydroxyethyl) terephthalate (BHET) as a coupling agent between rGO and Ti3C2Tx through covalent and hydrogen bonds. It is found that BHET can not only resist the weak oxidization of Ti3C2Tx to some degree but also prevent the self-stacking of Ti3C2Tx and rGO sheets. Then, B-rGO@Ti3C2Tx was used as a functional nanofiller and three-dimensional chain extender for preparing the waterborne polyurethane (WPU) nanocomposite through in situ polymerization. Compared with WPU nanocomposites with an equivalent amount of Ti3C2Tx/rGO@Ti3C2Tx, although containing an equivalent amount of BHET, WPU/B-rGO@Ti3C2Tx nanocomposites show significantly improved performance. For example, 5.66 wt % of B-rGO@Ti3C2Tx endows WPU with a high tensile strength of 36.0 MPa (improved by 380%), thermal conductivity of 0.697 W·m-1·K-1, electrical conductivity of 1.69 × 10-2 S/m (enhanced by 39 times), good strain-sensing behavior, electromagnetic interference (EMI)-shielding performance of 49.5 dB in the X-band, and excellent thermal stability. Therefore, the construction of rGO@Ti3C2Tx nanohybrids with the aid of chain extenders may unlock new possibilities of polyurethane as smart materials.
Keywords: MXene; bis(2-hydroxyethyl) terephthalate; composites; conductivity; in situ polymerization.