Halloysite‐reinforced thermoplastic polyurethane nanocomposites: Physico‐mechanical, rheological, and thermal investigations

Abstract Different thermoplastic polyurethane (TPU) nanocomposites with various amounts of halloysite nanotube (HNT) were prepared. The morphological, rheological, thermal, mechanical, and electrical properties of the nanocomposites were also investigated. Fourier‐transform infrared spectroscopy shows that increasing HNT results in increased degree of phase separation. Differential scanning calorimetry thermograms indicate positive effects of HNT on the hard phase crystallinity due to interactions between the surface functional groups of nanotubes and the polyurethane hard phase and also disinclination to form spherulites. According to the dynamic mechanical thermal analysis results, storage modulus of the nanocomposites increased up to 185% with increasing the HNT content in the experimental temperature window, which is in accordance with the tensile strength results. Mechanical analysis indicates that the modulus of nanocomposite increased up to 122% with increasing the HNT content. Rheo‐mechanical spectroscopy results showed that by the addition of low contents of HNT into the TPU matrix, the storage modulus did not show significant variations; however, an upturn in storage modulus was observed by increasing the amount of HNT to 4.2 wt%. In addition, the average volume conductivity of HNT‐reinforced nanocomposites was decreased comparing to the pure TPU even at low amounts of HNT. Therefore, addition of HNT into the TPU matrix resulted in higher mechanical properties in the related nanocomposites.