On the Mechanism of Swelling of Gel-Type, Macroporous and Hypercrosslinked Copolymers of Styrene

Gel type polymers, polymers of expanded structure and macroporous polymers of styrene mostly with 6 mole% of divinylbenzene have been obtained by suspension polymerization, expanded and macroporous structures being prepared in the presence of 1.5 volumes of toluene or iso-octane, respectively. All three types of copolymers were further converted into highly porous hypercrosslinked products by their intensive post-crosslinking with monochlorodimethyl ether. For all samples obtained, the inner specific surface area, total pore volume, apparent density, and uptake of toluene, methanol and water have been measured. It was found that the swelling of macroporous and hypercrosslinked porous polymers results in an increase in the volume of the polymeric phase and decrease in the volume of large pores with insignificant rise in the total size of the polymeric beads. Swelling of porous polymers thus mainly proceeds at the expense of space of internal voids.