The effect of annealing on the morphology and thermo-mechanical properties of TPU/CNS nanocomposites

Thermoplastic polyurethanes (TPUs) are highly versatile elastomers, commonly used in various applications due to their excellent mechanical properties and good chemical resistance. However, their low thermal stability and poor mechanical performance at elevated temperatures remain a significant challenge and limits their application. The utilization of nanofillers and thermal treatment (annealing) offers opportunities to enhance the mechanical properties and thermal stability of TPUs through distinct mechanisms. This study aims to uncover the potential synergistic effects of annealing on the enhanced properties of TPU nanocomposites containing branched carbon nanotubes (CNS). Annealing the TPU/CNS nanocomposites is conducive to the formation of a higher number of hydrogen bonded carbonyl species and a greater degree of microphase separation. In addition, the branches of CNS within the TPU matrix improve the hard segments (HS) segregation process into well-structured areas along the CNS boundaries. This process may establish a secondary network of the hard segment domains (HSDs) within the TPU matrix, contributing to the synergistic enhancement observed in the thermo-mechanical performance, particularly at elevated temperatures. These enhancements may broaden the application potential of TPUs in demanding environments, providing a promising solution to their traditional limitations.