Porosity of monolithic macroporous sorbents: Inverse hydrodynamic and size-exclusion chromatography study

Macroporous monolithic sorbents based on divinylbenzene are prepared in capillary tubes with the use of poor porogens of various sizes and molecular masses. The porosity of sorbents is studied via gravimetry and inverse hydrodynamic and size-exclusion chromatography methods. It is shown that all sorbents possess the biporous structure. Macropores with sizes on the order of a micrometer form an interconnected structure through which a solvent flows (flow-through pores). The diameter of impermeable pores is 30–40-molecular-mass solutes solely. As the molecular mass of the poor porogen decreases, the sizes of flow-through pores and the permeability of the monolith decline. At the same time, the fraction of free volume within the monolith accessible for the separation of polymer molecules is the highest for the sorbent prepared with the use of nonanol as a poor porogen.