Interfacial modeling of flattened CNT composites with cyanate ester and PEEK polymers

Flattened carbon nanotubes (flCNTs) are a promising form of composite material reinforcement because of their capacity for self-assembly and packing efficiency, which could ultimately lead to improved thermo-mechanical properties relative to current state-of-the-art composite materials. An important material design parameter for composite materials is the choice of polymer matrix, as characteristics of the reinforcement/polymer interface can have a significant effect on the bulk-level properties. Because flCNT-based composites are too expensive to develop via experimental trail-and-error approaches, the goal of this research is to use computational methods to drive their design via efficient polymer selection. Molecular dynamics modeling is used to predict the flCNT/polymer interface properties for a thermoplastic resin (polyether ether ketone - PEEK), and two thermosetting resins (fluorinated and non-fluorinated cyanate esters). For each polymer system, the interfacial interaction energy, flCNT shearing friction, and the transverse tension strength is predicted. While the PEEK and non-fluorinated cyanate esters demonstrate superior interaction energies (23.1% and 11.4% higher, respectively) compared to the fluorinated cyanate ester, the fluorinated cyanate ester has a significantly higher resistance to shearing with the flCNT surface (125% higher than PEEK and non-fluorinated cyanate ester). In pull-apart transverse tension simulations, the non-fluorinated cyanate ester system demonstrates the highest peak strength (8.53% higher than PEEK and fluorinated cyanate ester), while the fluorinated cyanate ester exhibits the highest toughness and stiffness (12.8% and 4.89% higher, respectively, than PEEK and non-fluorinated cyanate ester). Given equal weight, these predictions show that the fluorinated cyanate ester demonstrates the best overall compatibility with flCNTs.

Automated summary

Flattened carbon nanotubes (flCNTs) show potential as a form of composite material reinforcement with self-assembly and packing efficiency, and computational methods are used to drive their design through efficient polymer selection. The choice of polymer matrix is crucial for the properties at the reinforcement/polymer interface, impacting the overall performance of the composite materials. The predictions suggest that the fluorinated cyanate ester demonstrates the best overall compatibility with flCNTs, showing higher resistance to shearing and peak tension strength compared to other polymer systems.