Production of Porous Materials by “Reactive Gelation”
Massimo Morbidelli, Institute for Chemical- and Bioengineering, ETH Zurich, Wolfgang-Pauli-Str. 10, HCI-F-128, Zurich, 8093, Switzerland
Macroporous polymer materials have a wide spectrum of applications, including the chromatographic purification of biomolecules. Typically, these supports are synthesized by suspension polymerization in presence of porogens. Though remarkably simple, this process is not fully understood, and the control of the final structure is difficult. The approach presented here mimics the mechanism of pore formation occurring during suspension polymerization by a sequence of independent steps. Crosslinked particles are first produced by emulsion polymerization and then gelated in a controlled way, which determines size and type of porosity of the final material. The obtained gel is then post-polymerized to impart enough mechanical resistance to the material, to obtain a porous polymeric monolith. A comprehensive analysis of the impact of gelation and post-polymerization on the properties of the final product is carried out, using different polymeric supports (polystyrene, PMMA). Some chromatographic applications are shown where the main features of the monolith are exemplified.