Preparations of Polystyrene/Aluminum Hydroxide and Polystyrene/Alumina Composite Particles in an Ionic Liquid

Polystyrene (PS)/aluminum hydroxide (Al(OH)3) composite particles were successfully prepared by the sol−gel process of aluminum isopropoxide (Al(OPr i )3) in a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) using ammonium hydroxide (NH4OH) as a catalyst in the presence of PS seed. Transmission electron microscopy observation of ultrathin cross-sections of the composite particles revealed that the composite particles had a core−shell morphology consisting of a PS core and a Al(OH)3 shell having high crystallinity. The amount of secondary nucleated Al(OH)3 could be reduced by dropwise addition of NH4OH. Moreover, PS/η-Al2O3 composite particles were successfully prepared by heat treatment of PS/Al(OH)3 at 300 °C in N2 atmosphere, which is below the decomposition temperature of PS.