Porous polyHEMA beads prepared by suspension polymerization in aqueous medium

Abstract

Abstract A study was made of the effect of the type of low‐molecular‐weight porogen on the properties of polyHEMA beads (sphericity, bead size, porosity, and morphology), prepared by radical suspension copolymerization of 2‐hydroxyethyl methacrylate (HEMA) with ethylene dimethacrylate (EDMA) in aqueous dispersion. The porogen used was cyclohexanol, mixed with various alcohols, hydrocarbons, butyl acetate, or cyclohexanone. Spherical particles, with a size of hundreds of μm and a porosity of up to 68%, can be prepared using a mixture of cyclohexanol and 1‐octanol in a volume ratio of 3:2. The tendency for the particles to agglomerate, observed in the presence of benzyl alcohol, 1‐butanol, or cyclohexanone, can be a consequence of a change in the polymerization mechanism connected with the excessive solubility of these porogens, and thus also the initiator in water. © 1993 John Wiley & Sons, Inc.