Functionalized Si3N4 nanoparticles modified with hydrophobic polymer chains by surface-initiated atom transfer radical polymerization (ATRP)

In order to improve the dispersibility of nanoparticles in polymer matrix , a feasible processing way for grafting high density hydrophobic polymer on the surface of silicon nitride (Si 3 N 4 ) nanoparticles was carried out by an atom transfer radical polymerization (ATRP) method. The ATRP initiators were first immobilized on the surface of Si 3 N 4 nanoparticles by using 3-aminopropyltriethoxysilane coupling agent and 2-bromoisobutyryl bromide, and then the polymerization of methyl methacrylate was initiated and propagated on the surface of Si 3 N 4 nanoparticles by ATRP reaction. The chemical groups, size, morphology, grafting content, and colloidal thermal stability of PMMA–Si 3 N 4 particles were studied by Fourier transform infrared (FTIR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Results indicate that the grafting of polymer on the surface of Si 3 N 4 nanoparticles is successful and the grafting content of PMMA reaches 60.4%. Moreover, the grafted polymer chains have changed the surface properties of Si 3 N 4 nanoparticles and enhanced their dispersibility in organic media.