Nitroxide-Mediated Radical Polymerization of Styrene Initiated from the Surface of Titanium Oxide Nanoparticles

Abstract

Titanium dioxide (TiO 2 ) nanoparticles, with an average size of about 45 nm, were encapsulated by polystyrene using in situ nitroxide mediated radical polymerization in the presence of 3-aminopropyl triethoxy silane as a coupling agent and 2, 2, 6, 6-tetramethylpiperidinyl-1-oxy as a initiator. First, the initiator for nitroxide mediated radical polymerization was covalently bonded onto the surface of Titanium dioxide nanoparticles through our novel method. For this purpose, the surface of TiO 2 nanoparticle was treated with 3-aminopropyl triethoxy silane, a silane coupling agent, and then these functionalized nanoparticles was reacted with ± -chloro phenyl acetyl chloride. The chlorine groups were converted to nitroxide mediated groups by coupling with 1-hydroxy-2, 2, 6, 6-tetramethyl piperidine. These modified TiO 2 nanoparticles were then dispersed in styrene monomers to carry out the in situ free radical polymerization.