A systematic research has been conducted to investigate the matrix properties by introducing nanosize TiO2 (5 nm, 2.0-30% by weight) filler into a poly (methyl methacrylate) (PMMA) resin. A twin screw extraction process was developed to disperse the particles into the PMMA. The thermal, mechanical, and viscoelastic properties of the virgin PMMA and nanoTiO(2)-PMMA composite were measured. The nanofiller infusion improves the thermal, mechanical and viscoelastic properties of the PMMA. Nanocomposite shows increase in storage modulus (60%), rubbery modulus (similar to 210%), glass transition temperature (similar to 27%), crosslink density (similar to 213%), initial decomposition temperature (similar to 83% at 1% wt. loss), and activation energy (similar to 141%). Mechanical performance and thermal stability of the nanoTiO(2)-PMMA composites are depending on the dispersion state of the TiO2 in the PMMA matrix. Scanning electron microscopic study shows that the particles are well dispersed in the PM:MA matrix. They are correlated with loading. Kinetics for thermal degradation analysis was studies. The integral procedural decomposition temperature (IPDT) is enhanced (similar to 117%). The nanocomposites of high activation energy possess high thermal stability. Interrelation of T-g, crosslink density, IPDT, storage modulus, activation energy, and TiO2 weight percent are established. Various reasons for these effects in terms of reinforcing mechanisms have been discussed. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3396-3407, 2010