Atomistic measurement of the effect of interface tuning on the toughening and failure mechanisms of polypropylene nanocomposites toughened with nanofibrillated rubber

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  • In the present study, we investigate the roles of interface and interfiber interactions on the toughening and failure mechanisms of nanofibrillated rubber-toughened thermoplastic-based nanocomposites. Emphasis is placed on establishing a comprehensive theoretical and atomistic descriptions of the nanocomposite systems subjected to pull-out and uniaxial tests. Using the framework of molecular dynamics, the annealed melt-drawn nanofibers were spontaneously formed via the proposed four-step methodology. The generated nanofibers were then crosslinked using the proposed robust topology-matching algorithm, through which the chemical reactions arising in the crosslinking were closely assimilated. The interfiber interactions were also examined with respect to separation distances and nanofiber radius via nanofiber pair atomistic scheme and the obtained results were subsequently incorporated into the pull-out and uniaxial tests simulations. The results indicate that the compatibilizer grafting results in enhanced interfacial shear strength by introducing extra chemical interactions at the interface. In particular, it was found that the compatibilizer restricts the formation and coalescence of nanovoids, resulting in enhanced toughening effects. Together, we have shown that the presence of a small amount of well-dispersed rubber nanofibrillar network whose surfaces are grafted with maleic anhydride compatibilizer can dramatically increase the toughness and alter the failure mechanisms of the nanocomposites without deteriorating stiffness which is also consistent with the recent experimental observations. The interfacial failure mechanism was also investigated by monitoring of the changes in the atomic concentration profiles, mean square displacement and fractional free volume.

    Part of the Proceedings of the Canadian Society for Mechanical Engineering International Congress 2022.

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    Attribution-NonCommercial 4.0 International