Nano‐metal oxide fillers in thermo‐responsive polycaprolactone‐based polymer nanocomposites smart materials: Impact on thermo‐mechanical, and shape memory properties

The present study introduces the properties of three thermo‐responsive shape memory polymer nanocomposites (SMPCs), viz. SMPC–NiO (SMP with nickel oxide), SMPC‐Fe2O3 (SMP with iron oxide), and SMPC‐Fe2NiO4 (SMP with iron nickel oxide) along with the neat SMP blend. Styrene‐Butadiene rubber and poly ε‐caprolactone (PCL) polymer are the vital part, which forms the backbone of polymer‐elastomer blend matrix. This study helps to understand the effect and influence of these metal oxide nanofillers' integrated blend on their different inbuilt properties. The tensile test and dynamic mechanical analysis studies confirmed that SMPC‐Fe2NiO4 holds a large elastic modulus value and very rigid compared to other SMPCs. Thermal decomposition studies using differential scanning calorimetry, thermogravimetric (TG) analysis, and TG‐gas chromatography and mass spectrometry results show that the nanocomposites undergoes a two‐stage decomposition process. The shape memory test reveals that the time taken for temporary shape recovery is high for SMPC‐Fe2NiO4 because of its rigid nature and low for SMPC‐Fe2O3. The results revealed that, from this exploratory study, the integration of metal oxide nanopowder fillers, especially Fe2O3 with neat SMP, showed better properties. The graphical shows the mechanism of shape memory polymer nanocomposite (SMPNC) and switching of permanent and temporary shapes. The recoiling of polymer chains from a temporary shape to a permanent shape is the driving force for the shape recovery in SMP. At higher temperature (T > Tm), the chain segments are dislocated and gets fixed on cooling, which is the temporary shape. Upon triggering by higher temperature (T > Tm), the chain segments recoils and arranges in a more disordered permanent shape, as shown.