Improved water resistance,thermal stability,and mechanical properties of waterborne polyurethane nanohybrids reinforced by fumed silica via in situ polymerization

Abstract

In this study, a series of waterborne polyurethane/fumed silica (WPU/S) hybrids were prepared by an optimized in situ polymerization through a grafting process. Fourier transform infrared spectrum and X-ray diffraction confirmed the enhanced interfacial interactions between fumed silica particles and polyurethane (PU) segments. Atomic force microscopy demonstrated well dispersion of fumed silica in PU matrix and the rough surface of WPU/S hybrid films, which contributed to improved water resistance. The thermal stability of WPU was also improved by the incorporation of fumed silica, and the glass transition temperature of WPU/S increased compared with pure WPU. Moreover, as the content of fumed silica increased from 0% to 4%, the tensile strength of WPU/S increased from 29.0 MPa to 37.6 MPa without losing high elongation at break.