Modification of silica with PMMA via ultrasonic irradiation and its application for reinforcement of polyacrylates

Polymethyl methacrylate (PMMA) encapsulated silica nanocomposite particles were prepared by ultrasonically induced in situ polymerization of methyl methacrylate (MMA) on the surface of silica sol. The nanoparticles were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetry (TG), scanning electron microscopy (SEM). The results showed that core–shell structure nanocomposite particles with an average size of 36   nm were obtained, and the thickness of polymer encapsulating layer was about 8   nm. The pretreatment of silica sol with tert-butyl hydroperoxide (TBHP) and the addition of γ-methacryloxypropyl trimethoxysilane (MAPTS) significantly enhanced the encapsulation effect. Modified by the polymer layer, the silica particles could be well dispersed in matrices and utilized to improve the mechanical performance of polyacrylates.