Co-authors​ :

 Corrado SCIANCALEPORE (ITALY), Duccio GALLICHI NOTTIANI (ITALY), Daniel MILANESE , Marco ACTIS-GRANDE , Marta CERONI , Fausto FRANCHINI (ITALY), Emir POSKOVIC , Luca FERRARIS , Claudia INNOCENTI , Andrea CANESCHI  

Polymer-based composites with magnetic properties are promising materials able to combine the usual polymer features (low density, high electrical resistance, enhanced flexibility, and pro-cessability, etc.) with magnetic proprieties typically associated with ferro- or ferrimagnetic metals and alloys. In the present work, micrometric particles made of a Neodymium-Iron-Boron (NdFeB) alloy are compounded with a flexible thermoplastic matrix made of polybutylene adipate-co-terephthalate (PBAT). The NdFeB alloy is recovered from permanent magnets of ob-solete hard drives and is demagnetized, ground to powder under an inert atmosphere, and fi-nally, sieved to a particle size below 50 µm. The obtained powder is mixed with the polymer using a twin-screw extruder. The composite material containing the NdFeB particles is then processed to obtain a calibrated filament, used for the fused deposition modeling (FDM) three-dimensional (3D) printing of magnetic composites. Different routes to improve the ferromagnetic behavior are investigated: increasing the filler content up to 50 wt%, orientation of the particles during the 3D process by printing directly onto a permanent magnet and subsequent magnetization of the samples using a pulse magnetizer. Results of structural, thermomechanical, and magnetic char-acterizations are presented and discussed.