FORMATION OF POLYMERIC FOAMS FROM AQUEOUS FOAMS STABILIZED USING A POLYMERIZABLE SURFACTANT

Polymerization of foams formed by purging with nitrogen an aqueous pre cursor system made up of a polymerizable surfactant, a monomer, and a cross-linking agent yielded stable polymeric foams. The precursor syst em for foaming contained hydrophobic components (methyl methacrylate a s monomer and ethylene glycol dimethacrylate as cross-linking agent) i n water and was stabilized using the polymerizable surfactant potassiu m acrylamidostearate. The phase-behavior study for the precursor syste m was conducted followed by an investigation of the stability of the f oams obtained on purging with nitrogen. Sonicating the precursor syste ms during the process of purging with nitrogen gas followed by polymer ization resulted in aqueous foams having a uniform cell size. The aque ous foams were polymerized by a free-radical mechanism using photoinit iated and thermal techniques to form stable polymeric foams. The morph ology and density of the polymeric foams obtained was determined and o bserved to be significantly dependent on the composition of the aqueou s precursor that was foamed. These results indicate the feasibility of synthesizing polymeric foams without using hydrocarbon solvents or bl owing agents during polymerization. (C) 1993 John Wiley & Sons, Inc.