Magnetic Remote Activation of Shape Recovery in Nanocomposites Based on Tung Oil and Styrene

Abstract

The activation of unconstrained shape recovery in bio-based polymeric nanocomposites is successfully achieved using magnetic nanoparticle heating. The materials investigated in this work present several distinct physical and chemical characteristics worth pointing out: they can be deformed and the original shape can be recovered by remotely heating the samples above their switching temperature, which is determined by their glass transition temperatures. Also, their chemical composition is largely based on biomass (the polymeric matrix contains more than 50 wt.% of raw tung oil). Magnetic heating performance is strongly affected by both the physical properties and the concentration of the nanoparticles loaded into the matrix. The concentration of nanoparticles is associated with the formation of agglomerates or clusters, which determines the dipolar interactions among the nanoparticles. The particles used in this work are able to absorb enough energy from an alternating magnetic field to heat the matrix and initiate the shape recovery. Although the sample with the highest content of magnetic solute (10 wt.%) presents the highest degree of agglomeration, it is also the sample with the best remote activation of shape recovery, according to the temperature reached under magnetothermal measurements and the time of actuation.