High strain rate behaviour of polypropylene microfoams T. Gómez-del Río, M.A. Garrido, J. Rodríguez, D. Arencón and A.B. Martínez EPJ Web of Conferences, 26 (2012) 02006 Published online: 31 August 2012 DOI: 10.1051/epjconf/20122602006