SYNTHESIS OF UNIFORM PMMA MICROSPHERES EMPLOYING MODIFIED SPG (SHIRASU POROUS-GLASS) EMULSIFICATION TECHNIQUE

Application of the particulate microporous glass membrane (SPG) was ex tended to the synthesis of fairly monodisperse poly(methyl methacrylat e) (PMMA) microspheres. Hydrophilic monomers have been believed to yie ld polymer particles of a broad size distribution when the SPG techniq ue was employed. This difficulty was overcome by adopting the droplet swelling technique. The primary uniform emulsion composed of a mixture of hydrophobic diluent (and/or monomer), cosurfactant, and initiator was prepared with an SPG membrane and was allowed to absorb MMA (and d iluent) under the principle of the degradative diffusion process from droplets in the secondary emulsion. The coefficient of variation of PM MA spheres was around 10%. Porous PMMA spheres possessing up to 185 m( 2)/g of specific surface area were obtained as well as one-eyed sphere s and smooth and solid spheres. (C) 1995 John Wiley and Sons, Inc.