Enhanced Thermal And Tensile Behavior Of Mwcnt Reinforced Palm Oil Polyol-based Shape Memory Polyurethane

Shape memory polyurethane (SMPU) has received tremendous interest because of its low cost, low density, as well as easy processing. However, its inferior mechanical properties com-pared to shape memory alloys have constrained its application in a broad range of engineering areas. Nanofillers are commonly added to polymers to overcome the problem associated with low mechanical characteristics. This study aims to examine the effect of various loadings of multi- walled carbon nanotubes (MWCNT) on the thermal stability, soft segment crystallinity, tensile and shape memory behaviour of palm oil polyol based SMPU nanocomposites. The SMPU nanocom- posites were synthesised using a two-step polymerisation process. Microphase-separated SMPU
nanocomposites obtained as the differential scanning calorimetric analysis showed two melting transitions, which belonged to the soft and hard phase domains. Furthermore, it was found that MWCNT had acted as a nucleating agent, which promoted the crystallisation process of SMPU nanocomposites. The thermal stability and tensile properties of SMPU/MWCNT nanocomposites were enhanced significantly as the MWCNT was added to the SMPU matrix. A considerable enhancement in the shape fixity (SF) value was revealed for PU-30 and PU-40 samples with the addition of MWCNT. The shape recovery (SR) time of SMPU was faster for samples reinforced with MWCNT, whereas SF increased while SR decreased upon increasing the shape memory cycle.