Abstract: The adsorption and desorption isotherms of porous crosslinked polystyrene adsorbents with various contents of divinylbenzene were measured by nitrogen adsorption at 77 Kon Quantachrome Autosorb-MP-1 System. Their specific surface areas were determined on the basis of BETadsorption model. The total pore volumes and average pore sizes were also calculated according to adsorption isotherms. The pore size distributions in the polymeric adsorbents were statistically obtained by using a Quantachrome software following BJHtheory. The results showed that specific surface area was increased and average pore size was declined while crosslinking percentage, i.e. divinylbenzene content in a crosslinked polystyrene adsorbent, became higher. Although a pore size distribution peak in the diameter range of 4-7 nm appeared in all samples, mesopores and macropores were displayed on the pore size distribution patterns of porous crosslinked polystyrenes with crosslinking percentage less than₃₀%. The pore shapes in lowly crosslinked polystyrene adsorbents seemed cylindrical and "ink bottle" pores existing in highly crosslinked ones as observed from the hysteresis loops in their adsorption/desorption isotherms. Such a phenomenon of porous property should be controlled by the stability of pores in the processes of suspension copolymerization and the post treatment. When crosslinking percentage was low, small pores could be combined together into large ones in the processes owing to re organization of long polymeric chains between crosslinking sites. Otherwise, the re organization of polymeric chains hardly took place in highly crosslinked polystyrenes and the pores were almost kept stable.

Key words: Crosslinked polystyrene, Porous adsorbents, Mesoporous property, Adsorption