Manufacture of Porous Cross-Linked HEMA Spheres for Size Exclusion Packing Material

Abstract

2-Hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA) monomers and ethyleneglycol dimethacrylate (EDMA) as a cross-linker, were reacted with the initiator 2,2,azobis-2-methylpropionitrile (AIBN) in the presence of dodecanol. The effect of increasing concentrations of dodecanol, as a porogen agent, was evaluated. The radical polymerization was carried out using an in situ prepared Mg(OH)₂ gel, at 70°C for 5 h. Following polymerization, the suspension was eliminated by neutralization for recovery of beads. The spherical particles obtained were filtered, washed with methanol using simple extraction and using a Soxhlet thimble, and dried at 60°C under vacuum. Scanning Electron Microscopy (SEM) revealed regularly shaped spherical beads containing macropores. Nitrogen Sorption Analysis (NSA) and Mercury Intrusion Porosimetry (MIP) were performed for evaluation of surface area, pore size and pore volume.