Effects of temperature and hard segment content on the interfacial mechanical properties of graphene/thermoplastic polyurethane composites: A molecular dynamics study

YY Wang and GP Zou and L Shang, COMPUTATIONAL MATERIALS SCIENCE, 213, 111635 (2022).

DOI: 10.1016/j.commatsci.2022.111635

The effect of system temperature and hard segment content (HSC) on the interfacial mechanical behavior of graphene/thermoplastic polyurethane (TPU) nanocomposites is investigated by Molecular Dynamics (MD) simulations. The graphene opening and sliding pull-out simulations are carried out. The polymer consistent force field (PCFF) has been applied and validated by calculating the glass transition temperature of the neat TPU system. For better results interpretation, the maximum pull-out force and average pull-out force was used to characterize the interfacial strength of graphene/TPU nanocomposite in the opening and sliding mode, respectively. Besides, the number distribution of the hydrogen bonds (H-bonds) was used to clarify the reasons for the variation of pull-out force with different HSCs, and observe the evolution of the structural morphology. Based on the results obtained, the interfacial strength can be enhanced by decreasing the temperature or increasing the HSC both in the opening and sliding mode. Furthermore, the delay in the failure of interfacial strength due to the enhancement of entanglement strength can be achieved by adjusting the HSC of TPU to improve the uniform distribution of H-bonds in the opening mode. Additionally, we successfully applied the variation of the number of benzene rings with sliding distance to quantitatively describe the effects of temperature and HSC on the potential relationship between the interfacial strength and the mobility of polymer chains within the polymer-graphene interface in the sliding mode.

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