Abstract:
Polyetheramine modified montmorillonite (PEA-MMT) was prepared by inserting polyetheramine (PEA) into the montmorillonite layers through the way of ion exchange. The chemical structure of PEA-MMT was characterized by Fourier transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) analysis showed that the basal spacing of PEA-MMT was larger than that of unmodified MMT. The waterborne polyurethane (WPU)/polyetheramine modified montmorillonite (WPU/PEA-MMT) nanocomposite dispersions were prepared by incorporation of the functionalized montmorillonite during the emulsification process of the polyurethane prepolymer. The influence of the addition of PEA-MMT on the WPU properties including micromorphology, mechanical properties, water absorption and oxygen permeability were studied. Scanning electron microscopy (SEM) analysis confirmed that PEA-MMT was homogeneously dispersed in the waterborne polyurethane film. XRD demonstrated that the WPU segment was embedded in the middle of the PAE-MMT sheet, indicating the intercalation structure. Compared with pure WPU, when the mass fraction of PEA-MMT was controlled to be 3%, the tensile strength and Young's modulus were increased from 35 MPa and 13 MPa to 55 MPa and 44 MPa, respectively. Water resistance and oxygen barrier of composite were greatly improved by a synergistic effect of the lamellar structure of montmorillonite and the excellent interfacial interactions between PEA-MMTA nanosheets and WPU. When
m(PEA-MMT)∶
m (WPU)≥ 3%, the water absorption and oxygen permeability of the nanocomposite films and coatings were reduced by 83% and 24%, respectively.