Formation of porous epoxy monolith via concentrated emulsion polymerization

Step polymerization was introduced into the concentrated emulsion templating method and was illustrated with the preparation of porous epoxy monolith. A solution of diglycidyl ether of bisphenol-A (DGEBA), its curing agent low molecular weight polyamide resin, and surfactant nonyl phenol polyoxyethylene ether in 4-methyl-2-pentanon as a solvent was used as the continuous phase, an aqueous suspension of colloidal silica as the dispersed phase of the concentrated emulsion. After the continuous phase polymerized and the dispersed phase removed, a porous material is obtained. The key point in this work is to find a compromise between the rates of curing and phase separating and thus achieve a kinetic stability of the concentrated emulsion. The effects of loading of colloidal silica, the pre-curing of the epoxy precursors, and the volume fraction of the dispersed phase were systematically investigated.