Polycaprolactone/MSMA composites for magnetic refrigeration applications

A high filling load (62% weight) printable magnetic composite has been elaborated from the dispersion of magnetocaloric Ni45Mn36.7In13.3Co5 metamagnetic shape memory alloy microparticles into a PCL polymer matrix. The composite material has been prepared by solution method, resulting in a very homogeneous particles dispersion into the matrix. The structural transitions in the polymer are not affected by the addition of the metallic microparticles, which in turn results in a significant increase of the mechanical consistency. The good ductility of the elaborated composite allows its extrusion in flexible printable filaments, from which 3D pieces with complex geometries have been grown. The heat transfer of the composite material has been assessed from finite element simulation. In spite of the achievable magnetocaloric values are moderated with respect to the bulk, numerical simulations confirm that, in terms of heat transference, a PCL/Ni‐Mn‐In‐Co wire is more efficient than a bulk Ni‐Mn‐In‐Co cubic piece containing the same amount of magnetic active material. The quite good magnetocaloric response of the composite and the possibility to print high surface/volume ratio geometries make this material a promising candidate for the development of heat exchangers for clean and efficient magnetic refrigeration applications. Highlights 3D printable magnetic composites developed from dispersion of MSMA in PCL. High filling factor and uniform dispersion characterized by SEM. Inclusion of microparticles does not affect polymeric structural transitions. Metallic fillers improve DMA response of 3D printed pieces. FEM simulations endorse PCL/MSMA composites for magnetic refrigeration. PCL/Ni‐Mn‐In‐Co printable composites are promising candidates for development of high surface/volume ratio heat exchangers for magnetic refrigeration applications.