Preparation of Spherical Poly(methylsilsesquioxanes) Beads and Their Properties

The spherical poly(methylsilsesquioxane) (PMSQ) beads with the diameter of 2, 5 and 10 micron, respectively were prepared from methyltrimethoxysilane (MTMS) by two steps, acid hydrolysis and base condensation process in aqueous solution. Acetic acid and ammonium hydroxide were used to initiate the acid hydrolysis and base condensation, respectively. The bead size was affected and controlled by the reaction variables, such as the agitation speed, reaction temperature, solvent and concentration of monomer and catalyst. The prepared PMSQ beads were characterized by 29Si CP/MAS NMR and FT-IR. Especially in preparing the spherical PMSQ bead with the diameter of 10 micron, it was found that organic solvent was necessary to obtain the desired size compared with the preparation condition of 2 and 5 micron beads. The prepared PMSQ beads showed good thermal stability and compression recovery ratio. The haze value of PMSQ beads was remarkably higher than that of acrylic beads due to the relatively low refractive ind...