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High internal phase emulsion (HIPE) copolymer and interpenetrating network foams were prepared from 2‐ethylhexyl acrylate (EHA), styrene (S) and divinylbenzene (DVB) using a unique process. The morphologies, thermal properties and dynamic and static mechanical properties of these foams were investigated. The glass transition temperatures and damping properties of the EHA/S copolymer foams vary with its composition. IPN foams with very broad tan 5 peaks were obtained. The damping properties of IPN foams were tailored through changing copolymer composition and monomer composition. The IPN foams based on a copolymer foam and styrene had a broader tan δ peak, a higher glass transition temperature and a higher modulus than tne copolymer foams of similar overall styrene contents. It is therefore possible to prepare novel damping foams based on polyHIPE foams through the synthesis of interpenetrating polymer networks.

ABSTRACT: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 HIPE 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°C increased water absorption because of the removal of the residual salt. Adding a fluorinated comonomer to the HIPE reduced hydrophilicity and, thus, water absorption.

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ABSTRACT:Highly porous, open-cell polymers [poly-(HIPE)] were prepared by polymerizing the monomers in the continuous phase (ϳ 10%) of high internal phase emulsions (HIPE). This paper discusses using poly(HIPE) to remove bromoform from an aqueous solution through sorption, a combination of adsorption and absorption. The crosslinked polystyrene (xPS) and crosslinked poly(ethylhexyl acrylate) (xPEHA) had cell diameters from 1.5 to 15 m, intercellular pore diameters from 0.3 to 1.5 m, and densities of about 0.10 g/cc. The specific surface area of the glassy xPS increased from 7.9 to 28.8 m 2 /g on extraction in methanol, most likely due to crazing. The use of a toluene porogen in the xPS (xPS-T) reduced the density to 0.05 g/cc and yielded a rough surface with nanoscale porosity and a specific surface area of 132 m 2 /g. xPS and xPEHA, with very different molecular structures but with similar specific surface areas, exhibited similar sorption behavior. Extraction produced increases in the xPS and xPS-T sorption plateaus and sorption capacities. For larger specific surface areas, the sorption at low concentrations was relatively independent of concentration, indicating a case of adsorption with the sites occupied. For all the other cases, absorption seems to dominate and sorption is more strongly dependent upon concentration.