<p>The present invention relates to a foam comprising a polypropylene, wherein said polypropylene is produced in the presence of a metallocene catalyst, and the foam and/or the polypropylene has (have) a) a branching index g' of less than 1.00 and b) a strain hardening index (SHI@1s<SUP>-1</SUP>) of at least 0.30 measured by a deformation rate de/dt of 1.00 s<SUP>-1</SUP> at a temperature of 180 °C, wherein the strain hardening index (SHI) is defined as the slope of the logarithm to the basis 10 of the tensile stress growth function (Ig (?? <SUP>+</SUP>)</p>
