Effects of modified nano-silica on the microstructure of PVDF and its microporous membranes

In this study, effects of modified silica on the microstructure of polyvinylidene fluoride and its microporous membranes were investigated. The silica was modified by 3-Methacryloxypropyltrimethoxysilane to improve its compatibility with the polyvinylidene fluoride matrix. The relaxation time of polyvinylidene fluoride was markedly improved by modified nano-silica, especially at the loading of 0.1 wt‰. Effects of the modified silica on the nanocomposite microstructure, such as crystallization and orientation behavior, were studied in the manuscript. Furthermore, adding 3-Methacryloxypropyltrimethoxysilane modified silica could effectively handicap the relaxation of orientation structure in polyvinylidene fluoride and facilitate the formation of uniform lamellar structures which could be described by two-dimensional small-angle X-ray scattering testing. Finally, casting films with more uniform lamellar structure was also in favor of fabricating polyvinylidene fluoride microporous membranes by melt-stretching method.