Viscoelastic properties and thermal degradation kinetics of silica/PMMA nanocomposites

Abstract PMMA-silica nanocomposites were prepared using a bulk polymerization technique. Three organic silica groups, two modified with methyl groups and the third an octane, made these inorganic silica particles more hydrophobic. These silica/PMMA nanocomposites exhibited higher storage and loss moduli than those of pristine PMMA. The T g of these composites increased with the silica content. The thermal characteristics of these composites were also enhanced by incorporating silica into the PMMA matrix. The degradation temperature at 10% weight loss was approximately 30 °C higher than that of pristine PMMA, depending upon the silica content. The rate of weight loss at 220 °C for 2 h was also markedly reduced in the presence of these modified silicas. The results might be attributed to “trapping effect”. The activation energies for these silica/PMMA nanocomposites were enhanced according to Flynn, Ozawa–Flynn, and Kissinger methods.

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