Polymerized high internal-phase emulsions: Properties and interaction with water

The synthesis and characterization of novel polymerized high internalphase emulsions (polyHIPE) materials are described. Homogeneous, highly porous, low-density, open-cell crosslinked copolymers were prepared by polymerizing the continuous phase of HIPS containing styrene and varying amounts of 2-ethylhexyl methacrylate. The glass transition temperatures (T(g)s) of the homopolymers were similar to the literature values, but the copolymer T(g)s were lower than expected. These results indicate that the copolymer composition is richer in 2-ethylhexyl methacrylate than the feed composition. The homopolymer moduli, calculated from the foam moduli, were similar to the literature values. The influence of composition and surface treatment on the water absorbed by the foams was investigated. For example, washing a polyHIPE based on poly(ethylhexyl acrylate) in water at 70 degreesC increased water absorption because of the removal of the residual salt. Adding a fluorinated comonomer to the HIDE reduced hydrophilicity and, thus, water absorption. (C) 2002 Wiley Periodicals, Inc.