Multiscale modeling of fracture in polymer nanocomposite reinforced by intact and functionalized CNTs

In this research, mechanical properties and fracture mechanism of polymer nanocomposite reinforced by carbon nanotubes (CNTs) has been evaluated employing multiscale modeling method. Effect of CNTs’ structural defects and covalent bonds created during functionalization process are investigated in nanoscale analysis and the effect of CNTs’ dispersion, curvature and volume fraction are studied in microscale analysis. In microscale modeling both analytical and finite element methods are employed to investigate mechanical properties and their results are compared. It has been investigated that, according to mentioned parameters such as CNTs’ dispersion, volume fraction, functionalization and curvature in polymer matrix, both increase and decrease in ultimate strength of polymer nanocomposite are possible with respect to pure polymer. Moreover, polymer nanocomposite’s ultimate strength is increased and fracture brittleness is decreased significantly using functionalized CNTs. On the other hand, the CNT’s structural defects caused during functionalization process decrease polymer nanocomposite Young’s modulus. It also has been demonstrated that by increasing curvature, the improving effects of functionalized CNTs on mechanical properties of polymer nanocomposite, decrease obviously.