A novel route for the synthesis of poly(2-hydroxyethyl methacrylate) grafted TiO2 nanoparticles via surface thiol-lactam initiated radical polymerization



Hybrid nanocomposites of poly(2-hydroxyethyl methacrylate) (PHEMA) and TiO2 nanoparticles were synthesized via surface thiol-lactam initiated radical polymerization by following the grafting from strategy. Initially, TiO2 nanoparticles were modified by 3-mercaptopropyl trimethoxysilane to prepare thiol functionalized TiO2 nanoparticles (TiO2[BOND]SH). Subsequently, surface initiated polymerization of 2-hydroxyethyl methacrylate was conducted by using TiO2[BOND]SH and butyrolactam as an initiating system. The anchoring of PHEMA onto the surface of TiO2 nanoparticles was investigated by FTIR, 1H-NMR, XPS, TGA, and XRD analyses. The experimental results indicated a strong interaction between PHEMA and TiO2 nanoparticles owing to covalent bonding. The TEM and SEM images of PHEMA-g-TiO2 showed that the agglomeration propensity of TiO2 nanoparticles was significantly reduced upon the PHEMA functionalization. The molecular weight and polydispersity index of the cleaved PHEMA from the surface of TiO2 nanocomposites were estimated by GPC analysis. An improved thermal property of the nanocomposites was observed from TGA analysis. PHEMA-g-TiO2 nanocomposites were found to be highly dispersible in organic solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013