Reactor granule technology for fabrication of functionally advantageous polypropylene nanocomposites with oxide nanoparticles

Polypropylene (PP)/TiO2 and PP/Al2O3 nanocomposites were fabricated based on a new technology that involves the impregnation of metal alkoxide precursors in the porosity of PP reactor granule and subsequent conversion of the precursors into oxides during melt mixing. The so-called reactor granule technology enabled in-situ generation of highly dispersed oxide nanoparticles over a wide range of the loading extending up to 20 wt% without the use of dispersants. The confinement of metal alkoxide precursors in the porosity of the PP reactor granule and their facile chemical conversion into oxides were found to be crucial for the dispersion of the nanoparticles. The excellent dispersion of Al2O3 nanoparticles led to significant improvements in tensile properties, dielectric constants, and thermal conductivity as compared to conventional nanocomposites using a compatibilizer. It was concluded that the reactor granule technology is a simple and versatile way for the fabrication of polyolefin-based nanocomposites with superior functionalities.