Direct grafting poly(methyl methacrylate) from TiO 2 nanoparticles via Cu 2+ ‐amine redox‐initiated radical polymerization: An advantage of monocenter initiation

Cu 2+ can oxidize amines to generate radicals to initiate radical polymerization of electron‐deficient monomers under mild conditions. Here, CuSO 4 ‐catalyzed redox‐initiated radical polymerizations of methyl methacrylate from amino‐functionalized TiO 2 nanoparticles (TiO 2 ‐NH 2 nanoparticles) was performed to prepare TiO 2 nanoparticles grafted with poly(methyl methacrylate) (TiO 2 ‐ g ‐PMMA hybrid nanoparticles) in dimethylsulfoxide or N,N ‐dimethylformamide at 90°C. Infrared spectroscopy, thermogravimetric analysis, and X‐ray photoelectron spectroscopy confirmed the presence of the grafted PMMA and the grafting yield was about 50 wt%. Microscopy and particle‐size analysis indicated that TiO 2 ‐ g ‐PMMA nanoparticles had a good affinity to organic media. Because only aminyl radical (NH•) on TiO 2 nanoparticles formed in Cu 2+ ‐amine redox‐initiation step, there was no free PMMA chains formed during polymerization. Thus, our protocol provides a facile strategy to prepare inorganic/organic hybrid nanoparticles via one‐pot Cu 2+ ‐amine redox‐initiated free radical polymerization. POLYM. ENG. SCI., 55:735–744, 2015. © 2014 Society of Plastics Engineers