Abstract: A series of inorganic/organic nanocomposites was prepared by blending cage-like MMA-modified polyhedral oligomeric silsesquioxane (MMA-POSS) with PMMA in THF solvent. FT-IR and 29Si NMR were employed to characterize the structures of the nanocomposites. SEM micrographs showed that the as-prepared films were smooth with no aggregation of MMA-POSS observed. TG and DSC were used to investigate the thermal property, and tensile tests were carried out to determine the mechanical properties. It was found that a small amount of nano-sized MMA-POSS enhanced the thermal stability and mechanical properties of PMMA. When 1.0 wt % of MMA-POSS was incorporated, the Tg and Td increased by 16.9 oC and 21.0 oC, respectively.

Key words: nanocomposites, thermal properties, mechanical properties, poly(methyl methacrylate), polyformaldehyde