Effect of temperature on elastic properties of CNT-polyethylene nanocomposite and its interface using MD simulations

Abstract

This paper investigates the effect of temperature on the elastic modulus of carbon nanotube-polyethylene (CNT-PE) nanocomposite and its interface using molecular dynamics (MD) simulations, by utilizing the second-generation polymer consistent force field (PCFF). Two CNTs-armchair and zigzag-were selected as reinforcing nano-fillers, and amorphous PE was used as the polymer matrix. For atomistic modelling of the nanocomposite, the commercially available code Materials Studio 8.0 was used and all other MD simulations were subsequently performed using the open source code Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). To obtain the elastic modulus of the nanocomposite, stress-strain curves were drawn at different temperatures by performing uniaxial deformation tests on the nanocomposite material, whereas the curvatures of the interfacial interaction energy vs. strain curves were utilized to obtain Young's modulus of the interface. In addition, the glass transition temperatures of the polymer matrix and nanocomposites were also evaluated using density-temperature curves. Based on the results, it is concluded that, irrespective of temperature condition, a nanocomposite reinforced with CNT of larger chirality (i.e., armchair) yields a higher value of Young's modulus of the nanocomposite and its interface. It was also found that, at the phase transition (from a glassy to a rubbery state) temperature (i.e., glass transition temperature), Young's moduli of the polymer matrix, nanocomposite, and its interface drop suddenly. The results obtained from MD simulations were verified with results obtained from continuum-based rule-of-mixtures.

Engineering the mechanical properties of CNT/PEEK nanocomposites

“…[23][24][25] Recently, researchers have presented a series of works on MD simulation to predict the mechanical properties of nanocomposites. 26 There were some researches on the prediction of the Young's modulus of uniaxial CNT nanocomposites, including polyethylene (PE)-based matrix, 27 polyethylene-oxide (PEO)-based matrix. 28 Due to the difficulty in fabricating continuous CNT reinforced nanocomposites (a few hundred micrometers at the most 29 ), the mechanical properties of short and random CNT reinforced nanocomposites were mostly evaluated by MD simulation, such as CNT/PE system, 30 CNT/poly(methyl methacrylate) (PMMA) system, 31 carbon nanober (CNF)/polypropylene (PP) system.…”

Effect of temperature on properties of aluminum/single-walled carbon nanotube nanocomposite by molecular dynamics simulation

“…33 used experimental results and comprised the stress–strain curves of PP 3371 specimens with 10% nanoclay reinforcement at −54 ∘C, −20 ∘C,49C∘Cand71∘C, and showed that the Young’s modulus was decreased when the temperature increased. Also, Singh and Kumar 34 investigated the effect of temperature on elastic properties of CNT–polyethylene nanocomposite. Their results showed that by increasing the temperature from 100∘Kto400 ∘K, the elastic modulus decreased from 2.05GPa to 0.72GPa.…”

Interfacial characteristics of a carbon nanotube-polyimide nanocomposite by molecular dynamics simulation

“…Other significant factors appear to be the end cap of CNT, its diameter, and the strength of van der Waals interactions [32]. Recent MD simulations suggested that the interfacial energy and IFSS can be tuned through surface modifications of the CNT, especially hydroxyl groups at the ends [33][34][35][36].…”