Magneto-mechanical behavior of elastomeric carbonyl iron particles composite foams produced by foam injection molding

Foamed composite materials based on two thermoplastic elastomers reinforced with carbonyl iron particles (CIP) at 2% by volume were prepared by using foam injection molding. Nitrogen was used as physical blowing agent. Specimens were characterized by density measurements and morphological analysis. Foams based on neat polymers showed a well-developed cellular morphology only far from the injection point. On the contrary, composite foams showed a considerably increased homogeneity of the cellular structure morphology, with small cells found since the injection point. The magneto-elastic characterization of samples showed that reinforced samples (both unfoamed and foamed) showed a magneto-elastic behavior under a simultaneous application of a pre-strain and a magnetic field: the magnetic field induced response exhibited a butterfly shaped trend, typical of magnetostrictive materials.