Blends of styrene-butadiene rubber (SBR) and natural rubber (NR) were prepared and their morphology, transport behavior, and dynamic mechanical and mechanical properties were studied. The transport behavior of SBR/NR blends was examined in an atmosphere of n-alkanes in the temperature range of 25-60 degrees C. Transport parameters such as diffusivity, sorptivity, and permeability were estimated. Network characterization was done using phantom and affine models. The effect of the blend ratio on the dynamic mechanical properties of SBR/NR blends was investigated at different temperatures. The storage modulus of the blend decreased with increase of the temperature. Attempts were made to con:elate the properties with the morphology of the blend. To understand the stability of the membranes, mechanical testing was carried out for unswollen, swollen, and deswollen samples.