Thermoresponsive Shape Memory Polymer Based on Polylactic Acid/Styrene-Butadiene-Styrene Blends with Different Inorganic Metal Fillers

In this study, polylactic acid (PLA) blended with 30 wt% styrene-butadiene-styrene (SBS) (70PLA/30SBS) was added with different fillers; Erbium Oxide (Er 2 O 3 ), Halloysite Nanotubes (HNT) and Tungsten Carbide (WC 2 ) to investigate the effect of the filler on the shape fixity (R f ) and shape recovery (R r ) at different deformation and recovery times, rheological and morphological properties. The tubular structure of HNT led to the reduction of R f when immersed longer during the deformation phase. Meanwhile, the presence of Er 2 O 3 improved the R r and R r with longer deformation and recovery times, respectively. The blend with HNT has the highest viscosity while the blend with 70PLA/30SBS-Er 2 O 3 indicated lower viscosity than the unfilled blend. All filled blends indicated the sea-island structure with the SBS droplets in PLA continuous phase. The elements identification made on the surface of the samples illustrates that the fillers were well-distributed in 70PLA/30SBS blends. The insignificant improvement of shape memory in the presence of the thermal conductive fillers due to the dominance of the restriction of chain motion due to the presence of fillers compared with increment of thermal conductivity at low filler loading.