Polyurethane Solvent impregnation

As viewed by the present review, the most distinctive feature of solvent-impregnated resins as solid sorbents is their macroporous structure, which differentiates them from all other types and/or sorts of solid sorbents used in separation chemistry which are compact (granular) or foams (polyurethane). 

In another process, patented by Berens [67], the additive must again be solubilized in the supercritical solvent, as in Sand s process but, in this case, the patent is mainly concerned with reactive monomers that successively polymerize, modifying the host polymer. Nevertheless, in some examples (with a film of polyurethane), the problem of solid-drug impregnation is also considered. 

---