(399a) Preparation of Macro-Porous Media By Reactive Gelation and Application to Chromatography

Reactive Gelation is a multi-step process to prepare mechanically stable, porous materials from the aggregation of polymer nanoparticles¹. After preparing a dispersion of polymer particles in water by emulsion polymerization, these nanoparticles are swollen with monomer, aggregated and subsequently post-polymerized. The post-polymerization hardens the aggregates by forming covalent bonds between the primary particles. Depending upon the process conditions, either porous monoliths or micrometer-sized aggregates are formed. Both have been functionalized in several ways and applied in chromatography^2-4.

We are going to explain several distinct ways to carry out Reactive Gelation and analyze the obtained material using a variety of techniques including SEM, mercury intrusion, nitrogen porosimetry and microtomography. In particular, total porosity and pore size distribution are emphasized and similarities and differences between monoliths and micro-clusters are elucidated.

These media are then applied to high pressure liquid chromatography. The flow rate independent mass transport kinetics caused by their exclusively large pores will be shown using tracer peak moment analysis. After demonstrating possible functionalization methods both to anion and cation exchangers, several multi-species systems like isocratic standard monovalent anion separations, but also linear gradient elution separations of proteins are shown.