Effects of modified silica on morphology, mechanical property, and thermostability of injection-molded polycarbonate/silica nanocomposites

Nanocomposites of polycarbonate filled with untreated and modified silica nanoparticles were melt mixed and injection molded with a low melt temperature. The effects of modified silica and low-temperature melting on the morphology, mechanical property, and thermostability of composites were investigated. Scanning electron microscope images showed that uniform dispersion of agglomerates was formed by low-temperature melt blending. A slight reinforcing and toughening effect on tensile behavior of composites was obtained, and the modification of nanoparticles made the effect more remarkable. The storage modulus of composites measured by dynamic mechanical analysis increased observably as a function of silica content, especially for the composites with modified silica, but the T-g value changed little. Thermogravimetric analysis presented that thermostability improved dramatically after adding silica nanoparticles. In addition, the incorporation of modified silica into matrix showed a more significant improvement in thermostability at low loading.