Abstract: Porous poly（acrylic acid）-based polyHIPEs were prepared by the polymerization of oil-in-water high internal phase emulsions （O/W HIPEs） initiated by γ-ray radiation and redox system, respectively. Compared with normal dried gel materials used as hydrogels, polyHIPEs prepared from O/W HIPEs have higher porosity and a more uniform pore structure, and their pore sizes can be adjusted by changing internal phase volume. Observed by scanning electron microscope （SEM）, polyHIPEs obtained by γ-ray radiation polymerization were found to have a more ordered and completly porous structure than those obtained by redox initiation system. The adsorption tests of methylene blue （MB） on different samples showed that compared with those prepared by chemical method, polyHIPEs obtained by radiation method had a faster adsorption rate and a higher saturation adsorption capacity. The sample R-25-48 of γ-ray radiation polymerization for 48 h with an absorption dose of 151.2 kGy could adsorb up to 1175.9 mg of methylene blue per gram in 250 mg/L methylene blue solution, and the sample R-25-8 of radiation polymerization for 8 h with an absorbed dose of 25.2 kGy could absorb a lot of water, up to nearly 120 times its original weight, which means that theγ-ray radiation polymerization process affects the structure and properties of polyHIPE materials. The adsorption isotherms and kinetics models were used to fit the adsorption experimental results of MB on polyHIPEs obtained by γ-ray radiation polymerization. It is found that adsorption isotherm fits the Langmuir model and adsorption kinetics conforms to pseudo-second-order model, which indicates that the adsorption process is dominated by chemisorption with the mechanism of monolayer adsorption.

Key words: porous materials, oil-in-water high internal phase emulsions, acrylic acid, radiation polymerization, methylene blue adsorption