PMMA-titania nanocomposites: Properties and thermal degradation behaviour

Titania nanoparticles were prepared using a sol-gel method and calcination at 200 and 600 C in order to obtain anatase and rutile phases, respectively. The obtained powders were used to prepare PMMA-titania nanocomposites by a melt compounding method. The effect of the crystalline phase and the amount of titania, in the range 1-5 wt.%, on the morphology, mechanical properties and thermal degradation kinetics of PMMA was investigated by means of X-ray diffractometry (XRD), transmission electron microscopy (TEM), 13C cross-polarization magic-angle spinning nuclear magnetic resonance spectroscopy (13C1HCP-MAS NMR), including the measurement of proton spin-lattice relaxation time in the rotating frame (T1ρ(H)), in the laboratory frame (T1(H)) and cross polarization times (TCH), and dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), and Fourier-transform infrared (FTIR) spectroscopy. Results showed that both types of titania were well dispersed in the polymeric matrix, whose structure remained amorphous. The two types of nanoparticles influenced the degradation of the polymer in different ways because of their different carbon content, particle size and crystal structures.