Preparation and characterization of 2-hydroxyethyl methacrylate-based porous copolymeric particles

2-Hydroxyethyl methacrylate was copolymerized with three different comonomers, methyl methacrylate (MMA), styrene (St), and N-vinyl-2-pyrrolidone (NVP), respectively, to prepare porous particles crosslinked using ethylene glycol dimethacrylate (EGDMA) in the presence of an organic solvent, I-octanol (porogen), by means of suspension copolymerization in an aqueous phase initiated by 2,2-azobisisobutyronitrile. Nano-pores were observed in the particles. The pore size and the swelling properties of these particles can be controlled by changing comonomers or adjusting the crosslinker or porogen concentration. A lower crosslinker or porogen concentration favors generating smaller pores, whereas a higher concentration of a hydrophilic comonomer, higher concentration of crosslinker, and higher porogen volume ratio promote the generation of larger pores. In addition, the effects of the porous characteristics on the swelling properties were explored. The swelling capacity of the porous particles is reduced with the increase in the crosslinker concentration; however, there is a critical porogen volume ratio, in which the maximal swelling capacity is reached. Higher porosity in the particles and higher amount of hydrophilic comonomer favor a higher swelling capacity of the particles. (C) 2007 Wiley Periodicals, Inc.