PolyHIPEs are porous polymers typically synthesized within the external phases of water-in-oil high internal phase emulsions (HIPEs). PolyHIPEs usually have highly interconnected open-pore structures, low bulk densities, and high permeabilities. Typically, the polymerization mechanism used for polyHIPE synthesis is conventional free radical polymerization. Step-growth polymerizations are difficult to achieve within w/o HIPEs owing to the presence of the aqueous phase. This paper will describe the successful synthesis of porous, biodegradable poly(urethane-urea) (PUU) polyHIPEs through the step-growth polymerization of biodegradable triols and diols (polycaprolactones, polylactides, polyglycolides, and others) with diisocyanates. Two different polyHIPE synthesis routes were used to vary the urethane:urea ratio. In one-pot reactions, with all the components added to the HIPE, the urethane:urea ratio was difficult to determine a priori. In two-stage reactions, where the triols and diols were end-capped with diisocyanates before HIPE formation, the urethane:urea ratio was 2:1. The molecular structures, densities, porous morphologies, thermal properties, mechanical properties, and degradation of these PUU polyHIPEs were investigated. The suitability of these PUU polyHIPEs for tissue engineering applications was evaluated through cell growth. Histological cell cultures  showed that the cells adhered to the walls, proliferated, and filled the voids. Cell proliferation in polyHIPEs with relatively large voids (from one-pot reactions) was not as successful as in polyHIPEs with relatively small voids (from two-stage reactions).

Porous poly(urethane-urea)s through emulsion templating

248th National Meeting (2014)

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