CONICET | Buscador de Institutos y Recursos Humanos

Shape-memory polymers (SMP) have been object of intensive scientific research & development over the past years. Their unusual properties find several novel and important uses in biomedical and aerospace fields, among others [1-3]. This particular class of materials has the unique ability to keep a transient shape and recover its original one by the application of an external stimulus such as temperature, light, electric field, magnetic field, pH, specific ions or enzymes [1]. The interest behind developing SMP lies mainly in their ease of processing and low cost in comparison with shape memory alloys [3], but also by the possibility to modify their structure with nanoparticles (NPs), leading to the incorporation of interesting functional properties. In this regard, the addition of magnetite NPs could be a feasible alternative to add magnetic properties to segmented polyurethanes with thermo-activated shape memory properties and thus to introduce a novel activation mechanism via hyperthermia. In this context, the main aim of this work was to prepare segmented polyurethane nanocomposites with shape-memory behavior by incorporating magnetite NPs within a commercial polymeric matrix and characterize them in terms of their thermal, thermo-mechanical, mechanical and magnetic properties and morphology. Overall, the prepared films showed good shape-recovery response after the application of direct heating and by the application of a magnetic field. Mechanical tests indicated that the addition of NPs to some extent improved the elongation at break without affecting significantly both the modulus and the yield strength. The addition of NPs decreased to some extent their thermal stability, however did not impact considerably on the glass transition and melting temperatures and morphology.