Size-Controlling Synthesis of Narrowly Distributed Particles of Methylsilsesquioxane Derivatives

Abstract

Emulsion polymerization was used to prepare methylsilsesquioxane derivatives with an average particle size of 0.2−5.0 μm and various topological morphologies. Particles with an average particle size of 0.2−2.0 μm were prepared by emulsion polymerization using close to the critical micelle concentration of a nonionic emulsifier and a small amount of sodium hydroxide as a catalyst, whereas particles with an average particle size of 2.0−5.0 μm were obtained by suspension polymerization using a small amount of sodium hydroxide as a catalyst. Aggregation between the obtained particle colloids was not observed with the addition of an anionic emulsifier to the colloid solution at the earliest point in particle growth. A nonionic or cationic emulsifier was not effective, since the adsorption or diffusion of anionic emulsifier onto the particle colloids was accelerated due to the plus ζ potential of their surfaces.

Preparation of Copoly(styrene/butyl methacrylate) Beads and Composite Particles containing Carbon Black with Hydrophobic Silica as a Stabilizer in Aqueous Solution

“…To overcome these limitations in diameter Omi et al 6 employed counterion monomers and initiator in seed emulsion polymerization and obtained particles close to 1 μm in diameter. Noda et al 7 increased particle diameters to 2 μm with a nonionic surfactant and a small amount of sodium chloride as a catalyst by emulsion polymerization. Kim et al 8 synthesized polystyrene composite particles in the range of 75 to 950 nm in diameter containing metal stearates by emulsion polymerization.…”

Formation of Stable Nanoparticles of Poly(phenyl/methylsilsesquioxane) in Aqueous Solution

“…12 Nota et al prepared the PMSQ particles with an average diameter of 0.2-5.0 µm by emulsion polymerization of organoalkoxysilane. 13,14 Our former success in preparing the PPSQ nanoparticles has opened a new option in designing the nano-structured materials.The present study discloses the preparation of nanoparticles of poly(phenyl/methylsilsesquioxane) (PPMSQ) that are more stable than the PPSQ particles mentioned above. Those particles can readily be prepared by emulsion polymerization of the cohydrolysate that is formed by the hydrolysis of a mixture of TCP and TCM (Scheme 1).…”

“…12 Nota et al prepared the PMSQ particles with an average diameter of 0.2-5.0 µm by emulsion polymerization of organoalkoxysilane. 13,14 Our former success in preparing the PPSQ nanoparticles has opened a new option in designing the nano-structured materials.…”

Preparation of Nano-Particles of Poly(phenylsilsesquioxane)s by Emulsion Polycondensation of Phenylsilanetriol Formed in Aqueous Solution

“…7 With increasing interest in designing micro-and nano-structured materials, many attempts have been made to obtain nano-particles with suitable shapes. 8,9 Minami et al, for example, prepared PPSQ particles from organoalkoxysilane by using the sol-gel technique 709 …”

“…7 With increasing interest in designing micro-and nano-structured materials, many attempts have been made to obtain nano-particles with suitable shapes. 8,9 Minami et al, for example, prepared PPSQ particles from organoalkoxysilane by using the sol-gel technique and used them for preparing PPSQ thick films on a glass substrate for application to micro-optic devices. 10 However, the PPSQ particles prepared thus far were mainly of micron-size with a wide size distribution, and no report has appeared on the preparation of nanoparticles of PPSQ.…”