Preparation of Core/Shell Microspheres of Polymethylmethacrylate/Alumina by Mechanofusion as a Precursor of Hollow Alumina Microspheres

摘要

Core/shell microspheres of polymethylmethacrylate (PMMA) coated with Al_2O_3 were successfully fabricated by a mechanofusion system. The microshperes were subjected to calcination to give hollow Al_2O_3 microspheres. The Al_2O_3 shell structure was destroyed during a pre-firing or sintering process without the addition of fine SiO_2 powder. In contrast, addition of 5.0 or 10.0 wt percent SiO_2 was found to be effective for maintaining the original shell structure, while the size of hollow Al_2O_3 microspheres increased slightly and a small hole formed in each microsphere during the removal process of PMMA.