A Molecular Dynamics Study of the Stability and Mechanical Properties of a Nano-Engineered Fuzzy Carbon Fiber Composite

Hassan Almousa,Qing Peng,Abduljabar Q Alsayoud

doi:10.3390/jcs6020054

Abstract

Carbon fiber-reinforced polymer composites are used in various applications, and the interface of fibers and polymer is critical to the composites’ structural properties. We have investigated the impact of introducing different carbon nanotube loadings to the surfaces of carbon fibers and characterized the interfacial properties by molecular dynamics simulations. The carbon fiber (CF) surface structure was explicitly modeled to replicate the graphite crystallites’ interior consisting of turbostratic interconnected graphene multilayers. Then, single-walled carbon nanotubes and polypropylene chains were packed with the modeled CFs to construct a nano-engineered “fuzzy” CF composite. The mechanical properties of the CF models were calculated through uniaxial tensile simulations. Finally, the strength to peel the polypropylene from the nano-engineered CFs and interfacial energy were calculated. The interfacial strength and energy results indicate that a higher concentration of single-walled carbon nanotubes improves the interfacial properties.

Highlights

Greenhouse gases trap heat in the atmosphere, increasing Earth’s surface temperature from 1–4 °C by 2100 [1]
An (8,6) single-walled carbon nanotubes (SWCNTs) with a length of 2.5 nm and a diameter of 0.95 nm was built by the Visual Molecular Dynamics (VMD) extension of the nanobuilder tool [27]
Molecular dynamics (MD) deformation in the long direction with periodic boundary conditions in all directions was conducted to analyze the strength of the developed carbon fiber (CF) models

Summary

Introduction

Greenhouse gases trap heat in the atmosphere, increasing Earth’s surface temperature from 1–4 °C by 2100 [1]. The fuzzy fiber is hierarchical and shows enhanced fracture toughness, interlaminar shear strength, and thermal and electrical properties [11] To further understand this type of hierarchical fiber and its potential without the challenging experimental parametrization, an atomistic model framework was constructed for investigating the interface interaction between the fuzzy CF and the polymer matrix. A series of MD simulations were conducted first to construct the following components individually: CFs, single-walled carbon nanotubes (SWCNTs), and polypropylene (PP) as the matrix This model was subjected to uniaxial stress deformation through MD simulation. The motivation of this study is to demonstrate efficiently, via MD computational methods, the significance of nano-engineering CF surfaces with CNTs in thermoplastic-based composites as a valuable lightweight structure for transportation applications

Methods

Molecular Dynamic Simulations

Carbon Fiber Simulation

Uniaxial Stress Simulation

Carbon Fiber Model Properties

Conclusions