Transparent PMMA/silica nanocomposites containing silica nanoparticles coating under supercritical conditions

This work reports the preparation of PMMA/silica nanocomposites with high optical transparency and enhanced mechanical properties using a melt compounding method. The surface of SiO2 particles was modified with a γ-methacryloxypropyltrimethoxy silane coupling agent in a supercritical carbon dioxide-ethanol mixture and by conventional procedure. Dispersion of silica nanoparticles in ethanol at low temperatures plays an important role in deagglomeration and dispersion of nanosilica, which leads to the optimal particle-matrix bonding in composites. The optimal mechanical and optical properties were found for composites loaded with 5 wt% silica nanoparticles treated under supercritical coating method.

► Silica nanoparticles were coated under a supercritical condition.
► Mie and Rayleigh scattering theories were used for optical transmittance modeling.
► Mechanical and optical properties of nanocomposites are simultaneously improved.