Biobased waterborne hyperbranched polyurethane/NiFe2O4@rGO nanocomposite with multi-stimuli responsive shape memory attributes

Abstract

A biobased waterborne hyperbranched polyurethane nanocomposite was fabricated with nickel ferrite/reduced graphene oxide nanohybrid (NiFe₂O₄@rGO) by following an in situ polymerization technique. NiFe₂O₄@rGO was prepared through a hydrothermal method. The prepared nanohybrid and nanocomposite were characterized by using different spectroscopic and analytical techniques. Various properties of the nanocomposite were also evaluated. The nanocomposite demonstrated excellent thermal stability (initial degradation temperature up to 335 °C) and good mechanical properties (tensile strength 24.23 MPa, elongation at break 280% and toughness 28.35 MJ m⁻³). The nanocomposite also exhibited outstanding multi-stimuli responsive shape memory behavior under sunlight, thermal and microwave (300 W) irradiation. Both the polymer matrix and nano-filler acted complementarily towards an efficient shape recovery behavior. The performance of the nanocomposite was found to be dependent on the nanomaterial loading. Thus, the present study showed that the developed nanocomposite can be used as a high performing, non-contact triggered smart material for advanced shape memory application.