Effect of Loading and Surface Modification of Nanoparticles on the Properties of PMMA/Silica Nanocomposites Prepared via In-Situ Free Radical Polymerization

A number of batch polymerizations were performed to study the effect of pristine nanoparticle loading on the properties of PMMA/silica nanocomposites. In order to improve the dispersion of silica nanoparticles in the PMMA matrix, the silanol groups of the silica are functionalized with methacrylate groups and modified nanoparticles were used to synthesize PMMA/modified silica nanocomposites. Prepared samples were characterized by thermogravimetric analysis (TGA), dynamic light scattering (DLS), dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). According to the results, introduction of modified nanoparticles results in better thermal and mechanical properties than those of pristine nanoparticles. Also, surface modification and increasing silica nanoparticles result in variation of thermal degradation behavior of nanocomposites. The best improvement of the mechanical and thermophysical properties is achieved for nanocomposites containing 7wt.% silica nanoparticles.