Micromorphology and mechanism of polyurethane/polyacrylate membranes modified with epoxide group

Polyurethane/polyacrylate (PUA) composite emulsions were synthesized based on the presence of preformed polyurethane chains. Glycidyl methacrylate (GMA), an acrylate monomer, was introduced into the system. Surface tension measurements assured the surface activities of the polyurethane emulsion. Dynamic light scattering (DLS) result showed that the average diameters and polydispersity were increased with the increment of GMA content. X-ray photoelectron spectroscopy (XPS) result indicated that the upper surface was rich in PU phase. The peak deconvolution results of XPS also confirmed the formation of PUA. The crosslinking degree and tensile strength were both enhanced due to the reaction between the carboxyl groups and the epoxide groups. Thermo gravimetric analysis (TGA) of the membranes showed that the thermal stability enhanced and the decomposition temperature was much higher than the pure PU membrane. X-ray diffraction (XRD) analysis, together with differential scanning calorimetry (DSC) results, demonstrated the amorphous nature of the PU matrix. Atomic force microscopy (AFM) observation performed the extremely flat membrane.