Synthesis and kinetics of graft polymerization of methy methacrylate from the RAFT coordinated surface of nano-TiO2

Polymer chains of PMMA were grown from nano titania (n-TiO2) by the reversible addition-fragmentation chain transfer polymerization process. The mechanism and kinetics of MMA polymerization from both solution and grafted from n-TiO2 were studied. The RAFT agent, 4-cyano-4-(dodecylsulfanylthiocarbonyl) sulfanyl pentanoic acid, with an available carboxyl group was used to anchor onto the n-TiO2 surface, with the S =C(SC12H25) moiety used for subsequent RAFT polymerization of MMA to form n-TiO2/PMMA nanocomposites. The functionalization of n-TiO2 was determined by FTIR, XPS, partitioning studies, and thermal analysis. The livingness of the polymerization was verified using NMR and GPC, while the dispersion of the inorganic filler in the polymer was studied using electron microscopy, FTIR, and thermal analysis. The monomer conversion and molecular weight kinetics were explored for the living RAFT polymerization, both in solution and grafted from n-TiO2, with first-order kinetics being observed in both cases. Increased graft density on n-TiO2 led to a lower rate of polymerization. (c) 2008 Wiley Periodicals, Inc.