Morphology, mechanical properties and thermal degradation kinetics of Zirconia-PMMA composites prepared by melt compounding

摘要

Zirconia nanoparticles were synthesized by means of a sol-gel method and embedded in poly(methyl methacrylate)\ud(PMMA) by melt compounding. The zirconia was well dispersed in the PMMA matrix, with only a few clusters, especially\udfor the highest investigated zirconia content. NMR results showed heteronuclear dipolar interactions involving the\udcarbons and the surrounding hydrogen nuclei. The effect of the amount of zirconia, in the range of 1–5!wt%, on the thermomechanical\udproperties and thermal degradation kinetics of PMMA was also investigated by means of dynamic mechanical\udanalysis (DMA), thermogravimetric analyses (TGA), and Fourier-transform infrared spectroscopy (FTIR). The presence of\udzirconia showed a decrease in the storage and loss moduli at lower temperatures, probably due to a plasticization effect. The\udpresence of zirconia in PMMA slightly increased its thermal stability, but the activation energies of thermal degradation for\udthe nanocomposites were significantly lower, at degrees of conversion higher than 0.3, than those of pure PMMA.