MAGNETIC NANOCOMPOSITES BASED ON SHAPE MEMORY POLYURETHANES

SOTO, G.D.; MEIORIN, C.; ACTIS, D.; MENDOZA ZÉLIS, P.; OSCAR MOSCOSO LONDOÑO; MURACA, DIEGO; MIRNA A. MOSIEWICKI; NORMA E. MARCOVICH

EUROPEAN POLYMER JOURNAL

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2018 vol. 109 p. 8 - 15

0014-3057

Shape-memory composites based on a commercial segmented polyurethane andmagnetite (Fe3O4) nanoparticles (MNPs) were prepared by a simple suspension castingmethod. The average sizes of individual magnetic particles/clusters were determined byTEM microscopy and corroborated from SAXS patterns. The magnetization propertiesof selected samples were evaluated using zero field cooling/field cooling (ZFC/FC)measurements and magnetization loops obtained at different temperatures. The resultsshowed that magnetization at high field (20 kOe) and coercitivity measured at 5 Kincrease with magnetite content and that all the composite films exhibit superparamagneticbehavior at 300 K. The specific absorption rate (SAR) of thenanocomposites was calculated by experimentally determining both the specific heatcapacity and the heating rate of the films exposed to an alternant magnetic field. Allnanocomposites were able to increase their temperature when exposed to an alternantmagnetic field, although the final temperature reached resulted dependent of the MNPsconcentration. What is more, a fast and almost complete recovery of the original shapeof the nanocomposites containing more than 3 nominal wt.% MNP was obtained by thisremote activation applied to the previously deformed samples.