This paper focuses on the development of swellable thermoplastic elastomer alloys based on elastomeric powder, polypropylene, and superabsorbent polymer. The mechanical and swelling properties of the resulting materials were investigated at varying concentrations of the components and by compatiblization between the rubber particles of the elastomeric powder and the polypropylene phase using the peroxide 2,5-dimethyl-2,5di (t-buthylperoxy)hexane as compatibilizer. The materials obtained could be processed by injection molding in the same way as thermoplastics. The mechanical and swelling properties of the materials could be controlled by shifting the concentrations of the components. The swelling properties in different swelling media were investigated. A maximum of 120% of the relative increase of mass was obtained using KOH solution. The positions of the SAP particles within the material were detected by a combined method of SEM and EDX scan. Elastomeric powder and thermoplastic build the matrix material, in which the SAP particles are embedded mechanically. A schematic illustration of the material structure was developed, and the liquid was suspected to be transported by diffusion into the material matrix as well as along the interface between SAP and the matrix material. The results obtained can be used for the design of improved sealing concepts, as they evidence a good method of using recycled elastomers. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1290-1296, 2011