Shape-Memory Polymer Nanocomposites of Poly(ε-caprolactone)\nwith the Polystyrene-<i>block</i>-polybutadiene-<i>block</i>-polystyrene-tri-<i>block</i> Copolymer Encapsulated\nwith Metal Oxides

Abstract

Shape-memory polymer\ncomposite (SMPC) blends with thermo-responsive\nshape memorizing capability have received increasing interest and\nhave been a grooming research area due to their various potential\napplications. In this work, we report three thermo-responsive SMPCs\nderived from poly­(ε-caprolactone) (PCL) and the polystyrene-<i>block</i>-polybutadiene-<i>block</i>-polystyrene-tri-<i>block</i> copolymer (SBS) encapsulated with CuO, Fe₂O₃, and CuFe₂O₄, namely, <b>SMPC–CuO</b>, <b>SMPC–Fe</b>_<b>2</b><b>O</b>_<b>3</b>, and <b>SMPC–CuFe</b>_<b>2</b><b>O</b>_<b>4</b>, respectively.\nWe have also synthesized the neat shape-memory polymer matrix <b>SMP</b> in the context of the effect of the metal oxide encapsulates\non the shape-memory property. Neat SBS rubber and PCL are used as\nthe polymer-elastomer blend matrix to form <b>SMP</b>. The objective\nof this study is to understand the effect of these three metal oxide\nnanofillers encapsulated within the <b>SMP</b> matrix and their\nthermal, mechanical, and shape-memory properties. Morphological, thermal,\nmechanical, and shape-memory properties of the prepared SMPCs are\ncompletely characterized. It is revealed that the addition of nano-metallic-oxide\nfillers into the polymeric matrix significantly improved the overall\nproperties of SMPCs. The tensile test confirmed that <b>SMPC–CuFe</b>_<b>2</b><b>O</b>_<b>4</b> possesses\na high tensile modulus and is found to be very rigid when compared\nto other SMPCs. The shape fixing property is found in the increasing\norder as follows: <b>SMPC–CuO</b> > <b>SMPC–Fe</b>_<b>2</b><b>O</b>_<b>3</b> > <b>SMP</b> > <b>SMPC–CuFe</b>_<b>2</b><b>O</b>_<b>4</b>. The better thermal, mechanical,\nand shape-memory performances were shown by the <b>SMPC–Fe</b>_<b>2</b><b>O</b>_<b>3</b> composite,\nand thus, it can be considered as the better shape-memory polymer\nnanocomposite among all others. An optimum storage modulus was attained\nby <b>SMPC–Fe</b>_<b>2</b><b>O</b>_<b>3</b> among the SMPCs. More interestingly, we\nhave developed a microvalve actuator system using <b>SMPC–Fe</b>_<b>2</b><b>O</b>_<b>3</b>,\nwhich could be useful for promising microsystem applications.