Study on morphology and mechanical properties of PMMA-based nanocomposites containing POSS molecules or functionalized SiO2 particles

Abstract

Nanocomposites of octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) and functionalized SiO2 were investigated in order to determine the effect of particles on the morphology and mechanical properties of PMMA. The outcome of the study suggested that functionalized SiO2 and octavinylPOSS molecule had different morphology. As proved by X-ray diffraction and transmission electron microscopy analysis, the crystal structure of OVPOSS molecule was significantly different from amorphous aggregates of functionalized SiO2. With the additional particles in the nanocomposites, the sizes of octavinylPOSS and functionalized SiO2 began to reduce. This illustrated that the separation of aggregates led to the formation of irregular POSS molecules and amorphous SiO2 particles varied. Differential scanning calorimetry analysis indicated that PMMA-POSS nanocomposites had a homogeneous system. However, there was a significant phase separation at 3 wt.% SiO2. PMMA-SiO2 nanocomposites displayed lower reinforcing effects than expected, based on the mechanical properties of nanocomposites containing OVPOSS molecules.