Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness

摘要

Polylactide-based polyurethane shape memory nanocomposites (Fe3O4/PLAUs) with fast magnetic responsiveness are presented. For the purpose of fast response and homogeneous dispersion of magnetic nanoparticles, oleic acid was used to improve the dispersibility of Fe3O4 nanoparticles in a. polymer matrix. A homogeneous distribution of Fe3O4 nanoparticles in the polymer matrix was obtained for. nanocomposites with low Fe3O4 loading content. A small. agglomeration was observed for. nanocomposites with 6 wt% and 9 wt% loading content, leading to a small. decline in the. mechanical properties. PLAU and its nanocomposites have glass transition around 52 degrees C, which can be used as the triggering temperature. PLAU and its nanocomposites have shape fixity ratios above 99%, shape recovery ratios above 82% for the first cycle and shape recovery ratios above 91% for the second cycle. PLAU and its nanocomposites also. exhibit a fast water bath or magnetic responsiveness. The magnetic recovery time decreases with an. increase in. the loading content of Fe3O4 nanoparticles due to an. improvement in heating performance for increased weight percentage of fillers. The nanocomposites have fast responses in an alternating magnetic field and. have potential application. in biomedical areas such as intravascular stent.