Preparation and characterization of hypercrosslinked resins with bimodal pore size distribution and controllable microporosity

Hypercrosslinked polystyrene resins with bimodal pore size distribution and controllable microporosity were prepared by combining traditional suspension polymerization and post crosslinking technique. The volume ratio of divinylbenzene (DVB) in monomer mixtures was kept at 20%, while vinylbenzyl chloride (VBC) concentration was progressively reduced to investigate effect of post crosslinking degree on the pore structure of the hypercrosslinked species. The results indicated that higher VBC concentration in monomer mixtures led to greater surface area, smaller average pore size and higher microporosity. Moreover, bimodal distribution of pore size could be observed for the final resins. The mesopore fraction should be derived from the pores originally present in precursor resins, while the micropore fraction was originated from the post crosslinking.